152 908 low straumann bone level implant system scientific summary by Straumann AUNZ

Straumann 速 Bone Level Implant System Scientific Summary

Straumann速 Bone Level Implant System

The ITI (International Team for Implantology) is the academic partner of Institut Straumann AG in the areas of research and education.

Contents

I. Introduction II. Five biological principles of Bone Control Designâ&#x201E;˘ 1. Respecting the biological distance

2 3 4

2. Biomechanical implant design

3. Optimal positioning of smooth and rough surfaces

4. Microgap control

5. Implant surface osseoconductivity

III. StraumannÂŽ Bone Level implants: Scientific research program 1. Biomechanical property tests

9 10

Ultimate strength

Fatigue strength

Screw-loosening test

Microgap measurements

Conclusions on biomechanical property tests

2. Pre-clinical studies

Implant primary stability

Bone maintenance around Bone Level implants

Inter-implant bone maintenance

Conclusions on pre-clinical research

3. Clinical studies

Early implant placement in the esthetic zone (SMILE I: 12 months)

Early implant placement in the esthetic zone (SMILE I: 36 months)

Bone maintenance around Bone Level implants in submerged and non-submerged techniques

Conclusions on clinical research

References 36

I. Introduction

The Straumann® Bone Level implant system provides surgical and restorative flexibility in all approved indications, designed to secure component positioning, and supports bone preservation for predictable esthetic results. Moreover, it respects five biological key principles (see Section II) leading to predictable performance. The Straumann® Bone Level implant system is based on a large pre-clinical and clinical research program. The constant flow of independent scientific publications makes it clinically well documented and validated by dental professionals. Fig. 1: Straumann® Bone Level implant body design.

Straumann® Bone Level implants have a cylindrical outer contour. The core is cylindrical in the apical region becoming slightly conical in the coronal part of the implant wich results in a mild taper. The implant features a thread to the top with a thread pitch of 0.8 mm (identical to the thread on Straumann® Tapered Effect implants) for extensive interlocking with the bone (Fig. 1). The Straumann® Bone Level implant system includes the three standard endosteal diameters for Straumann® Implants (3.3, 4.1, and 4.8 mm) and is available in lengths of 8, 10, 12, and 14 mm (Fig. 2).

coronal Ø

Ø 3.3 mm

Ø 4.1 mm

Ø 4.8 mm

apical Ø

Ø 3.3 mm

Ø 4.1 mm

Ø 4.8 mm

color code

yellow

Fig. 2: Bone Level implant portfolio overview.

red

green

II. Five biological principles of Bone Control Design™

Bone Control Design™ is an implant design based on the five

and soft tissue stability. The “Bone Control Design™“ is ex-

biological key principles for optimized crestal bone preservation

plained in the following diagram.

1. 5.

Respecting the

biological distance:

Biomechanical implant design:

Implant surface osseoconductivity:

3. 4.

Optimal positioning of smooth and rough surfaces:

Microgap control:

1. Respecting the biological distance

3. Optimal positioning of smooth and rough surfaces

Minimizes bone resorption by providing enough space for soft

A rough surface extending over the bone crest can support

tissue growth.

crestal bone maintenance. The rough-smooth surface interface of the Straumann® Bone Level implant is located at the top of the

2. Biomechanical implant design

implant shoulder.

Optimized fatigue strength, flat neck portion (similar to Standard/Standard Plus/Tapered Effect implants), optimized force

4. Microgap control

transmission through CrossFit Connection, hybrid self-tapping

The Straumann® CrossFit connection has a very precise fit. The

implant body design and tapered effect thread geometry. These

microgap is extremely small (42–197 nm). This makes microbial

lead to even stress distribution through the bone, and minimize

contamination very unlikely, and helps preserve bone.

bone microdamage and resorption. 5. Implant surface osseoconductivity Straumann® Bone Level implants feature the SLActive ® Surface for improved osseointegration (Oates et al. 2007). 3

1. Respecting the biological distance

Inherent biological dimensions exist for the hard and soft tissues around both dental implants and teeth. Crestal bone normally remodels to a point 1.5 – 2.0 mm apical to the implant-abutment interface after implant placement (Albrektsson et al. 1986). This is the biological distance or biological width, which begins to form immediately after exposure of the implant to the oral environment. It is the result of localized soft tissue inflammation at the implant-abutment interface, where the soft tissue attempts to establish a mucosal barrier around the dental implant. This mucosal barrier needs certain spatial dimensions. Vertical (apical) movement of the biological distance after implantation results in crestal bone resorption. However, this can be avoided by encouraging horizontal movement of the biological distance so that the necessary dimensions are maintained but crestal bone is preserved. Therefore, one method to try to control crestal bone loss is to alter the horizontal position of the implant-abutment interface. This horizontal component can be manipulated by the use of an abutment with a smaller diameter (’platform switching’), which places the implant-abutment interface at a more medial location (Gardner 2005). Long-term follow-up has suggested that platform-switched implants show less change in vertical crestal bone height than conventionally restored implants (Lazzara/Porter 2006). The crestal bone level is, therefore, stabilized at or near the level of the implant collar, minimizing bone resorption (Chiche 2004). With the Straumann® Bone Level implant, the interface with the abutment is above the crestal bone level and is shifted horizontally, therefore, designed to maximize the opportunity to maintain crestal bone (Fig. 1).

Fig. 1: Straumann® Bone Level implant: designed to maximize crestal bone maintenance.

2. Biomechanical implant design

The biomechanical design of an implant is important in determining its potential in maintaining the crestal bone, both directly and indirectly (Misch et al. 2006). Indirect factors include the stability and fatigue strength of the implant system and its connections. Primary stability of the implant in the bone has a direct influence on crestal bone maintenance. Micromovements between the implant and the bone should be kept to a minimum for adequate osseointegration to take place. Other direct factors include the distribution of stress forces induced in the surrounding bone, which are affected not only by implant design, but also by the type of abutment connection (Cehreli et al. 2004). The mechanical configuration of the implant-abutment interface also appears to have an important influence. A flat-top implant-abutment interface increases the interfacial shear stress in comparison to a conical implant-abutment interface (Hansson et al. 2000). For the conical interface, the stress forces are located more apically in the bone, away from the more delicate marginal bone areas. It has been suggested that implants with a conical interface can withstand greater axial load before bone resorption (Hansson 2003). Implants with a conical abutment interface also show significantly improved mechanical stability compared to implants with a butt-joint interface (Norton 1997). Straumann 速 Bone Level implants have a conical implant-abutment connection designed to evenly distribute stress patterns to the surrounding bone (Fig. 2). The design and thread pitches of the Straumann 速 Bone Level implant also create good primary stability (Toyoshima et al. 2011) preventing micromotion and supporting crestal bone maintenance (Buser et al. 2009; Cordaro et al. 2010; Buser et al. 2011; Hammerle et al. 2012).

Fig. 2: Optimal dispersion of forces by the Straumann速 Bone Level implant.

3. Optimal positioning of smooth and rough surfaces The location of the border between the rough and smooth surfaces of the implant in relation to the bone crest is an important factor when considering the maintenance of crestal bone. Greater crestal bone loss has been observed when implants are placed with the rough-smooth border below the alveolar crest, and crestal bone loss is reduced when the border is above the alveolar crest (Jung et al. 2008; Cochran et al. 2009). For two-piece implants, the level of bone resorption was found to be determined by the location of the implant-abutment interface (Hermann et al. 2000). Alomrani et al. (2005) used SLA® Implants a in pre-clinical study, which either had a SLA® Surface covering the length of the implant or had a 1.8 mm coronal machined collar. Both implants were placed at three different levels in relation to the bone crest. Bone loss was significantly reduced when the top of the SLA® Surface was placed above the crestal bone level and greater when the top of the SLA® Surface was below the crestal bone level. The rough-smooth surface border in Straumann® Bone Level implants is located at the very top of the implant shoulder, which is located above the alveolar crest at implant placement. The rough surface, therefore, extends above the alveolar crest level – thus, providing a larger surface area available for osseointegration supporting the maintenance of crestal bone (Buser et al. 2009; Cordaro et al. 2010; Buser et al. 2011; Hammerle et al. 2012).

Fig. 3: Straumann® Bone Level implant: optimal positioning of smooth and rough surfaces.

4. Microgap control

The microgap is a small gap located at the interface between the implant and the abutment. It is a feature of all two-part implant systems (i.e. those with a separate abutment); there, the internal implant cavity is exposed to the peri-implant region. The size of the microgap determines the extent of the exposure. Minimizing the gap can, therefore, reduce the risk of exposure. Todescan et al. (2002) suggested that the presence of the implant-abutment interface only causes excessive additional bone loss if the size of the microgap is > 5 μm. The microgap of the implant-abutment interface in Straumann ® Bone Level implants was measured by Institut Straumann AG (at the Paul Scherrer Institut) using a focused ion-beam technique. This showed that the internal CrossFit ® Implant-abutment connection is very precise and that the microgap is in the range of 42–197 nm (Habersetzer 2012). In the in vitro evaluation of the implant-abutment bacterial seal of Straumann® Bone Level implants, Dibart has shown that the seal provided by the locking taper of the CrossFit ® Connection design of Straumann® Bone Level implants is hermetic with regard to bacterial invasion (Dibart et al. 2005). esigned A conical abutment connection, as used in Straumann® Bone Level implants, is d to avoid bacterial contamination and to reduce the risk of micromovements in clinical situations. The crestal bone maintenance is, therefore, supported (Dibart et al. 2005; Dibart et al. 2010).

Fig. 4: Straumann® Bone Level implant: keeping the microgap away from the bone.

5. Implant surface osseoconductivity

The physical and chemical properties of the surface of dental implants can have a profound effect on the speed and efficiency of osseointegration as well as the process by which a structural and functional connection is achieved between implant and bone. Changing the surface properties can affect the activity of osteoblasts (Oates et al. 2007) and, subsequently, the formation of bone at the implant surface. Enhancing the osseointegration process can, therefore, result in reduced healing times, higher implant stability, increased treatment predictability and subsequent improvements in bone maintenance. Straumann has developed a new chemically modified titanium surface (SLActive ®) using the well-documented surface topography of SLA®. The SLActive ® Surface is chemically activated, with a high surface free energy, a reduced atmospheric hydrocarbon contamination and a strong hydrophilicity. The water contact angle for SLActive ® is 0° compared to 139.9° for SLA® (Zhao 2005; Rupp et al. 2006). The SLActive ® Surface is characterized by a hydroxylated/hydrated titanium oxide film. The modification of the surface is performed under nitrogen (N2) conditions, and the resulting high surface free energy is maintained by storage in an isotonic saline solution. Based on pre-clinical and clinical studies, the chemically modified, hydrophilic surface of SLActive ® allows enhanced osseointegration compared to SLA® (Schwarz et al 2007; Oates et al. 2007) and may, therefore, result in reduced healing times, higher implant stability, and increased treatment predictability. The use of the SLActive ® Surface on Straumann® Bone Level implants, therefore, increases the likelihood of maintaining the crestal bone level compared to SLA® (Oates et al. 2007).

Fig. 5: SLActive® is chemically activated and has a highly hydrophilic surface.

III. Straumann ® Bone Level implants: Scientific research program

Biomechanical property tests #

Topic

Authors

Reference

Ultimate strength

D. Müller (Müller 2006)

Data on file: BL implant ultimate strength: internal reports: B390B, B368 A, B364. (Müller 2006)

Fatigue strength

D. Müller (Müller 2006; Müller 2007)

Data on file: BL implant fatigue tests: internal reports: B440 series B, B390B, B417 series B

Screw-loosening test

B. Schaap and H. Hornberger (Schaap/ Hornberger 2007)

Data on file

Microgap measurements

P. Habersetzer (Habersetzer 2012)

Data on file

Pre-clinical studies #

Topic

Authors

Reference

Primary stability

T. Toyoshima et al. (Toyoshima et al. 2011)

Primary stability of a hybrid self-tapping implant compared to a cylindrical non-self-tapping implant with respect to drilling protocols in an ex vivo model. Clin Implant Dent Relat Res. 2011 Mar;13(1):71–8.

Primary stability and removal torque

J. Gottlow and L. Sennerby (Gottlow/Sennerby 2010)

The influence of surface and implant design on stability of five commercial titanium implants. A biomechanical study in rabbits. Academy of Osseointergation 25th anniversary meeting, Orlando, FL, USA, March 4–6, 2010.

Bone maintenance around bone level implants

R. Jung et al. (Jung et al. 2008)

The influence of matching and non-matching implant and abutment diameters on radiographic crestal bone levels in dogs. J Periodontol 2008;79(2):260–270.

Inter-implant bone maintenance

N. Elian et al. (Elian et al. 2011)

Effect of inter-implant distance (2 and 3 mm) on the height of inter-implant bone crest: A histomorphometric evaluation. J Periodontol 2011 Apr;71(4):546–9.

Clinical studies #

Topic

Authors

Reference

Early implant placement in the esthetic zone

D. Buser et al. (Buser et al. 2009)

Early implant placement with simultaneous guided bone regeneration following single-tooth extraction in the esthetic zone: 12-month results of a prospective study with 20 consecutive patients. J Periodontol 2009;80(1):152–162.

Early implant placement in the esthetic zone

D. Buser et al. (Buser et al. 2011)

Stability of Contour Augmentation and Esthetic Outcomes of Implant Supported Single Crowns in the Esthetic Zone: 3-Year Result of a P rospective Study With Early Implant Placement Post Extraction. J Periodontol 2011 March; 82(3):342–9.

Bone maintenance around bone level implants in submerged and non-submerged techniques

C.F. Hammerle et al. (Hammerle et al. 2012)

Submerged and transmucosal healing yield the same clinical outcomes with two-piece implants in the anterior maxilla and mandible: interim 1 year results of a randomized, controlled clinical trial. Clin. Oral. Implants. Res 2012;23(2):211–219.

Bone maintenance around bone level implants in submerged and non-submerged techniques

L. Cordaro et al. (Cordaro et al. 2010)

Oral presentation of the 2 years follow up data: Submerged vs. non-submerged healing of implants for single tooth replacement in the esthetic zone: results from a multicenter RCT. European Association for Osseointegration, 19 th Annual Scientific Meeting, Glasgow, 6–9 October 2010.

1. Biomechanical PROPERTY tests

Even before they are manufactured, Straumann® Implants have to prove that their biomechanical properties are sufficient for the required tasks. After the computer-aided design phase, a large number of promising variants are tested by finite element analysis in which computers simulate the biomechanical forces acting on the implant-

Biomechanical PROPERTY tests

abutment assembly during chewing. This helps when investigating how the forces are transmitted to the surrounding bone and in identifying designs of high biomechanical stability. The ’winners’ are then manufactured and subjected to mechanical testing in the laboratory. A number of additional tests are also performed, which include measuring the microgap and confirming a tight screw fit after cyclical mechanical loading. This process is a substantial part of product development according to the Straumann® Bone Control Design™ Concept. The aim is to generate one specific and optimized implant design that has passed all property tests and shows state-of-the-art bio mechanical properties.

Ultimate strength Müller D., Bone Level implants ultimate strength test: internal reports: B390B, B368 A, B364. (Müller D. 2006)

Ultimate strength [N]

In the static test made in 2006, the implant-abutment system is exposed to a static force, where the ultimate strength is mea-

1200

sured. The ISO 14801 test simulates the maximum possible force

1000

on the implant-abutment system as in a single bite-clenching

800

scenario. In order to show that in single-bite cases the implant-

600

strength of the system has to be higher than the mean maximal

400

biting force.

200 0

Test set-up and end-point Static compression tests were performed (Wieland/Hornberger 2007) according to ISO 14801 (International Organization for

BL 3.3

BL 4.8

BL 4.1

Fig. 1: Ultimate strength of Straumann® Bone Level implants of three different diameters.

Standardization 2011) for Straumann® Bone Level implants of 3.3, 4.1, and 4.8 mm in order to measure the maximal ultimate strength of Straumann® Bone Level implants. Key findings The ultimate strength of Straumann® Bone Level implants is presented in Fig. 1. Maximum bite force according to tooth position is presented in table 1. Key conclusions A static test is meant to evaluate the maximum possible force on the implant-abutment system, simulating the single bite-clenching scenario. From this, we can conclude that Straumann® Bone Level implants have the necessary ultimate strength to withstand the single bite-clenching scenario with no deforma-

Tooth

Women

Woman

Men

Mean

93.88

38.16

146.17

44.44

95.75

36.59

139.30

51.40

119.68

42.58

190.31

79.36

178.54

77.29

254.08

72.20

206.01

86.52

291.36

57.29

234.46

70.53

306.07

41.99

221.71

73.08

294.30

55.92

Biomechanical PROPERTY tests

abutment system is not permanently deformed, the ultimate

Tab. 1: Descriptive statistics of the single-tooth maximum bite forces from central incisor (1) to second molar (7) (in N, left and right average) in healthy young adults (36 men and 16 women) (Ferrario et al. 2004).

tion, therefore, allowing Straumann® Bone Level implants to be used in all indications according to approved instructions for use (Fig. 1 and Tab. 1).

Fatigue strength Müller D., Bone Level implant fatigue tests: internal report B440 series B; B390B; B417 series B, B399A, B399C (Müller 2006 and 2007)

The fatigue test for implant-abutment systems is designed to simulate a normal day-to-day chewing situation. According to S akaguchi et al. (1986) and Rosentritt et al. (2006), chewing comprises between 650 and 2100 cycles per day (240 000

Biomechanical PROPERTY tests

and 800 000 cycles per year) in humans. Dynamic fatigue testing exposes the implant-abutment system to a cyclic load of 5 million cycles, which approximately corresponds to between 6 years (800 000 chewing cycles per year) and 20 years (240 000 chewing cycles per year) of implant-abutment system use. Test set-up and end-point Straumann® Bone Level implant-abutment systems have undergone dynamic fatigue testing according to the ISO 14801 requirement (Fig. 1). The implant-abutment system has an angle of 30° relative to the acting force and a bone resorption of 3 mm

Fig. 1: Fatigue test set-up, according to ISO 14801. (1) Block into which the implant is fixed. (2) Axes of the block. (3) Implant-abutment-crown system. (4) Block which creates cyclic force on the abutment. (F) Cyclic force on the system.

is simulated. This corresponds to a worst-case scenario and is in excess of (i.e. twice as high as) the standard criteria for implant success as defined by Albrektsson et al. (Albrektsson et al. 1986), which indicate an acceptable bone loss of 1.5 mm in the first year and 0.2 mm per year thereafter.

BL implant

Fatigue

Internal report

diameter

strength [N]

number

BL 3.3 mm Ti

180–215

B399C–B440B

Abutment types

Straight abutment Angled abutment

The aim of these tests was to measure the fatigue strength of Straumann ® Bone Level implants. Benchmarking the fatigue test results of Straumann® Bone Level implants with a mean chewing force in the mouth allow to show that Straumann® Bone Level implants have the required fatigue strength and could be used in all indications according to approved instructions for use.

BL 3.3 mm

180–220

B399A–B444

Roxolid ®

Straight abutment Angled abutment

BL 4.1 mm

320*

B417B

Ti abutment

BL 4.8 mm

440*

B390B

Meso abutment

Tab. 1: Fatigue strength of Straumann® Bone Level implants.

Key findings and conclusion The fatigue strength of Straumann® Bone Level implants (Tab. 1) shows that Straumann® Bone Level implants have the required strength to be used in indications as specified in the approved instructions for use.

* T he fatigue tests results for 4.1 mm and 4.8 mm Bone Level implants were done only for indicated types of abutments.

Screw-loosening test B. Schaap and H. Hornberger. Bone level implant. Screw loosening test. Internal report 2007. (Schaap/Hornberger 2007)

During cyclic loading in the patient’s mouth, screws and, sub sequently, abutments may become loose. In order to prove the reliability of the Straumann® Bone Level implant system, screwloosening tests were conducted.

Implant and abutments were set up according to the test instructions (to 35 or 15 Ncm torque) (Fig. 1). The system underwent cyclic loading for 2 million cycles at different force levels. Measurements of screw-loosening torque were taken. Key findings and conclusion The results showed that Straumann® Bone Level implants are reliable regardless of the abutment type (cement-retained or screwretained). The average screw-loosening torques were only 20 %

Fig. 1: Test set-up for screw-loosening test. (1) Block in which the implant is fixed. (2) Axes of the forces. (3) Implant/abutment/crown system. (4) Block which creates cyclic force on the abutment. (F) Force.

Biomechanical PROPERTY tests

Test set-up and end-point

lower than the tightening torque) (Fig. 2), which indicates that the internal CrossFit ® connection prevents any screw-loosening during normal implant-abutment use.

40 35

Torque [Ncm]

30 25 20 15 10 5 0 160 N

185 N

240 N

280 N

300 N

240 N

150 N

Cem

Cem s-screw

Cem

Anatom 15 deg

Temp

NC M0

RC M

Fig. 2: Average loosening torque (M) only 20 % lower than tightening torque (M0). Cem = Cementable abutment; Anatom = Anatomic abutment; Temp = Temporary abutment; NC = Narrow CrossFit ®; RC = Regular CrossFit®.

Microgap measurements P. Habersetzer. Bone level implant. Microgap measurement with focused ion beam scanning electron microscope technique. Internal report. January 2012. Data on file. (Habersetzer 2012)

Test set-up and end-point

Conclusions on microgap measurements

Cut and polished micrographs were prepared and analyzed by

▪▪ Microgap measurements confirmed the high precision of the

the focused ion-beam technique at the Paul Scherrer Institut (Fig. 1) to measure the microgap of the Straumann Bone Level ®

Biomechanical PROPERTY tests

implant.

▪▪ The Straumann® CrossFit connection is demonstrated to be hermetic with regard to bacterial invasion in vitro. (Dibart et al. 2005; Dibart et al. 2010).

Fig. 1: Example of a cut and polished Fig. 2: Microgap measurements of implant-abutment interface sample implant-abutment interface. for the focused ion-beam technique.

Key findings and conclusion The focused ion-beam technique shows that the internal CrossFit ® connection of the Bone Level implant is very precise. The size of the microgap between the implant and abutment lies within a range of 42 –197 nm (Fig. 2) (Habersetzer 2012). The precision of the Straumann® CrossFit connection limits possible micromovements during abutment attachment. This minimizes bone microdamage for good crestal bone level maintenance (Cochran et al. 1997; Hermann et al. 2000; Hermann et al. 2001a; Hermann et al. 2001c; Piattelli et al. 2003; Lazzara/ Porter 2006). The size of the microgap is extremely small, which makes bacterial contamination very unlikely. (Dibart et al. 2005; Dibart et al. 2010).

Bone Level implant CrossFit ® Connection (Habersetzer 2012).

Conclusions on biomechanical property tests ▪▪ The fatigue strength of tested Straumann® Bone Level implants shows that they may be used in all indications: from single-gap restoration to the a pproved instructions for use (Müller 2006; Müller 2007).

▪▪ No screw-loosening was found in the dynamic testing of Straumann® Bone Level implants (Wieland/Hornberger 2007).

▪▪ Microgap measurements confirmed the high precision of the Bone Level implant CrossFit ® Connection (Habersetzer 2012).

▪▪ The Straumann® CrossFit Connection is demonstrated to be hermetic with regard to bacterial invasion in vitro (Dibart et al. 2005; Dibart et al. 2010).

Biomechanical PROPERTY tests

full-e dentulous restoration depending on their position as described in

2. Pre-clinical studies

The preceding biomechanical property tests demonstrated that the Bone Level implant design was suitable for in vivo trials, which provided the first evidence of biological performance and considerably reduced the risk for patients in subsequent clinical studies. The main focus of the in vivo testing was the bone preservation for submerged and non-submerged Straumann速 Bone Level implants at different heights as well as the 足effect on bone maintenance between two implants placed adjacent to each other at

pre-clinical studies

different distances.

Implant primary stability T. Toyoshima, W. Wagner, M.O. Klein, E. Stender, M. Wieland, B. Al-Nawas. Primary stability of a hybrid self-tapping implant compared to a cylindrical non-self-tapping implant with respect to drilling protocols in an ex vivo model. Clin Implant Dent Relat Res 201113(1):71–78. (Toyoshima et al. 2011)

Primary stability of implants, which is one of the fundamental

Materials and methods

criteria influencing implant success, depends greatly on the

The hybrid self-tapping implants and cylindrical non-self-tapping

geometry of the implants (i.e. length, diameter, shape and

implant were placed in porcine iliac cancellous bone (Fig. 1;

thread) as well as the surgical technique, volume, and me

Fig. 2).

chanical quality of the local bone. Modification of the implant design can optimize primary stability in critical bone quality

Ten implants of each type were inserted using either a standard

situations (Lioubavina-Hack et al. 2006). One approach that

or under-dimensioned drilling protocol. Implant-bone interface

has been suggested is to place a conical implant in a standard

stability was evaluated by maximum insertion torque (Periotest ®;

parallel-sided hole. The idea behind this approach is to induce

Siemens, Bensheim, Germany), resonance frequency analysis

controlled compressive forces in the cortical bone layer to in-

and the push-out test (Fig. 3, 4).

crease primary stability as the implant is inserted. Based on this idea, the hybrid self-tapping* Straumann® Bone Level implant combining the advantages of a conical implant with those of a cylindrical shape. The aims of this study were to evaluate the primary stability of Level implant and the Straumann® Tapered Effect implant) compared with a cylindrical non-self-tapping implant (Straumann® Standard Plus implant) and to elucidate the relevance of drilling

50 40 30 20 10 0 BL

protocols on primary stability in an ex vivo model.

Standard drilling Under-dimensioned drilling

pre-clinical studies

two types of hybrid self-tapping implants (Straumann® Bone

Maximum insertion torque [Ncm]

was specifically designed for use in bones with critical quality

Fig. 3: Insertion torque. With under-dimensioned implant-bed preparation, insertion torque was higher than for standard implant-bed preparation. Both Bone Level and Tapered Effect implants showed higher insertion torque values than Standard Plus.

Fig. 1: Design comparison Standard Plus, Tapered Effect and Bone Level implants.

Value of push-out test [N]

250 200 150 100 50 0 Standard Implant

Tapered Effect Implant

Standard Plus Implant

Bone Level Implant

1.25 mm

0.8 mm

Fig. 2: Thread comparison Standard Plus, Tapered Effect and Bone Level implants.

Standard drilling Under-dimensioned drilling

Fig. 4: Push-out torque. The results for push-out torque were similar to insertion torque measurements, i.e. higher values for the undersized implant bed and higher values for Bone Level and Tapered Effect implants as compared to Standard Plus.

* T he term “self-tapping” refers to the Bone Level implant body design only and means hybrid tapered implant body design.

Results In each drilling group, the maximum insertion torque values of

Using maximum insertion torque and push-out tests, the results

Bone Level and Tapered Effect implants were significantly higher

revealed a significantly higher stability of hybrid self-tapping im-

than for the Standard Plus (p = 0.014 and 0.047, respectively)

plants in both drilling groups in cancellous bone compared to

(Fig. 3). In each group, the Periotest 速 Values of the Tapered 足Effect

that of a cylindrical non-self-tapping implant. Primary stability is,

were significantly lower than for the Standard Plus (p = 0.036

therefore, influenced by the geometry of the implant. The high

and 0.033, respectively). The Periotest 速 Values of Bone Level

primary stability achieved by Bone Level implants in this situation

and Tapered Effect were significantly lower in the group of un-

indicates that their use may be predictable in low-density bone.

der-dimensioned drilling than standard drilling (p = 0.002 and 0.02, respectively). In the resonance frequency analysis, no statistical significances were found in implants between or within the two groups. In each group, the push-out values of Bone Level and Tapered Effect implants were significantly higher than for the

pre-clinical studies

Standard Plus (p = 0.006 and 0.049, respectively) (Fig. 4).

Key findings and conclusion

Implant Stability measured by removal torque J. Gottlow and L. Sennerby. Influence of surface and implant design on stability of five commercial titanium implants. A biomechanical study in the rabbit. Academy of Osseointegration 25th Anniversary Meeting, Orlando, FL, USA, March 4–6 2010, Abs. 193. (Gottlow/Sennerby 2010)

The aim of the experimental investigation was to compare im-

of four control implants (A, B, C and D) were rotated into posi-

plant stability as assessed by removal torque measurements be-

tion and placed in the other leg (n = 15). The implant stability

tween five commonly used dental implants representing different

was assessed by removal torque evaluation after 3 and 6

surface characteristics and geometries.

weeks.

Materials and methods

Results

The study was performed on 40 rabbits. Straumann Bone Level

Mean removal torque values (Fig. 2) and shear strength values

implants with the SLActive ® Surface (test) and four different types

(Fig. 3) showed significant differences between SLActive ® and

of implants with non-hydrophilic surfaces (control) were evaluat-

control implants: OsseoSpeed™, Tapered Screw Vent ®, Screw-

ed. Each of the 120 implants was studied for 3 and 6 weeks

Plant™ and GS II Fixture at 3 and 6 weeks.

(i.e. 15 per competitor and 4 sets of 15 Straumann Implants) ®

allowing for direct comparison (Fig. 1, Tab. 1). The split-leg ran-

Key findings and conclusion

dom design allowed the direct comparison of test and control

The SLActive ® Bone Level implants showed significantly higher

pairs of implants in tibial metaphyses and the distal femoral con-

implant stability compared to the implants with non-hydrophilic

dyles of rabbits. Test implants were placed in one leg, and three

surfaces as assessed by removal torque evaluation.

BL RC SLActive

(Ø 4.1 mm/length 8 mm)

AstraTech™

Zimmer ®

OsseoSpeed

Tapered Screw Vent

™

(Ø 4 mm/8 mm)

(Ø 3.7 mm/8mm)**

Implant Direct ®

Osstem™

ScrewPlant™

GS ll Fixture

(Ø 3.7 mm/8 mm)

(Ø 4 mm/8.5 mm)

pre-clinical studies

Straumann ®

Fig. 1: Straumann® and competitor implants included in the study.

BL implant diameter

Fatigue strength (N)

Straumann®

Osseospeed™

Tapered Screw

ScrewPlant™

GS II Fixture

Vent® Dimensions (µCT)

3D Roughness (CWLM)

Hydrophilicity

Mean radius

1.91 mm

1.85 mm

1.64 mm

1.59 mm

1.79 mm

Length (Cylindrical Part)

7.3 mm

7.5 mm

6.9 mm

7.3 mm

8.1 mm

Surface Area

104.8 mm2

110.3 mm2

98.4 mm2

99.3 mm2

120.5 mm2

Average mean deviation Sa

1.05 µm

0.60 µm

0.54 µm

0.77 µm

0.64 µm

Max. peak to valley height St

6.91 µm

4.21 µm

3.99 µm

5.48 µm

4.32 µm

Skewness Ssk

0.15

–0.05

–0.28

–0.15

–0.13

Dynamic Contact Angle

0°

138°

120°

112°

124°

Tab. 1: Measured surface properties of test and control implants.

3 weeks

Removal torque value [Ncm] Mean ± StDev

140 120

***

6 weeks

** ***

***

100 80 60 40 20 0 Straumann ® BL RC SLActive ®

Osseospeed™

Tapered Screw Vent ®

ScrewPlant™

GS II Fixture

Straumann ® BL RC SLActive ®

Osseospeed™

Tapered Screw Vent ®

ScrewPlant™

GS II Fixture

ScrewPlant™

GS II Fixture

Fig. 2: Removal torque values (means ± SD) after 3 and 6 weeks. **p ≤ 0.01; ***p ≤ 0.001; paired t-test.

3 weeks

Shear strength values [N/mm 2]

pre-clinical studies

***

6 weeks

*** ***

***

6 5 4 3 2 1 0 Straumann ® BL RC SLActive ®

Osseospeed™

Tapered Screw Vent ®

ScrewPlant™

GS II Fixture

Straumann ® BL RC SLActive ®

Osseospeed™

Tapered Screw Vent ®

Fig. 3: Removal torque values (means ± SD) after 3 and 6 weeks. **p ≤ 0.01; ***p ≤ 0.001; paired t-test.

** F igure 1, 2 and 3 have been presented (Gottlow et al., AO Meeting, Orlando, FL, USA, March 4–6, 2010, Abs P193) Figure 3: Shear strength values calculated by Institut Straumann AG and approved by authors based on Figure 2 and 3 ** Tapered Screw Vent ® implant is also available with 4.1 mm diameter OsseoSpeed™ and Astra Tech™ are registered trademarks of Astra Tech AB, Sweden. Tapered Screw Vent ® and Zimmer ® are registered trademarks of Zimmer Dental Inc USA. ScrewPlant™ and Implant Direct ® are registered trademarks of Implant Direct, USA. Osstem™ is a trademark of Osstem Company Ltd., Seoul, Korea.

Bone maintenance around Bone Level implants R.E. Jung, A.A. Jones, F.L. Higginbottom, T.G. Wilson, J. Schoolfield, D. Buser, C.H. Hämmerle, D.L. Cochran. The influence of matching and non-matching implant and abutment diameters on radiographic crestal bone levels in dogs. J Periodontol 2008;79(2):260–270. (Jung et al. 2008)

The aim of this study was to evaluate crestal bone changes around Straumann® Bone Level implants with smaller abutment diameters placed at different levels relative to the alveolar crest. Materials and methods In 5 dogs, a total of 60 Bone Level implants with smaller abutment diameters were placed bilaterally, either submucosally or transmucosally. In each side of the mandible, the implants were randomly placed with the implant shoulder either at the level of the alveolar bone crest or 1 mm above or below (Fig. 1). In the transmucosal group, the healing abutments had different lengths so that the final occlusal height was the same for each implant. Healing abutments were placed on the submucosal implants after 4 weeks. Prostheses (gold crowns) were placed on

Fig. 2: Submucosal implants 6 months after loading. Note the slight bone growth of the middle implant between crown placement and 6-month follow-up.

titanium meso abutments on all implants 12 weeks after implant placement. pre-clinical studies

A radiographic analysis was performed at implant placement, crown placement, and every month for up to 6 months. The dogs were sacrificed 6 months post loading, and the specimens were processed for histological and histometric evaluation.

Submucosal group

+1 mm

–1 mm

0 mm

Transmucosal group

Fig. 3: Transmucosal implants 6 months after loading.

Results For both groups, very small changes in the crestal bone level were detected in the X-rays (Fig. 2, 3). For implants placed submucosally, the mean bone change 6 months after loading was +0.17 mm (slight bone gain),

+1 mm

–1 mm

0 mm

–1.32 mm and –0.15 mm for implants placed above, below, or at the crestal bone level, respectively (Fig. 4).

Fig. 1: Submucosal and transmucosal groups with Bone Level implants placed either at the level of the alveolar bone crest or 1 mm above or below.

Corresponding bone loss for transmucosal implants placed above, below, and at the crestal bone level was –0.20 mm,

0.17 mm

–1.32 mm

–0.15 mm

+1 mm

–1 mm

0 mm

–1.40 mm and –0.47 mm, respectively (Fig. 5). No significant differences in bone loss or the level of bone-to-implant contact (BIC) were noted between submucosal or transmucosal implants. The bone loss was greater at implants placed below the level of the crestal bone, however, the distance from the implant shoulder to the first BIC with these implants was similar to that for implants placed at the level of the crestal bone (mean 0.19 mm and 0.26 mm for submucosal implants, mean 0.14 mm and 0.44 mm for transmucosal implants). Key findings and conclusion (1) Straumann® Bone Level implants show very small changes in the crestal bone level after 6 months of loading. (2) There is no significant difference between submucosal and transmucosal

pre-clinical studies

approaches.

Fig. 4: Crestal bone changes in the submerged group 6 months after loading.

–0.20 mm

–1.40 mm

–0.47 mm

+1 mm

–1 mm

0 mm

Fig. 5: Crestal bone changes in transmucosal group 6 months after loading.

Inter-implant bone maintenance N. Elian, M. Bloom, M. Dard, S.C. Cho, R.D. Trushkowsky, D. Tarnow. Effect of inter-implant distance (2 and 3 mm) on the height of inter-implant bone crest: a histomorphometric evaluation. J Periodontol 2011;82(12):1749–1756. (Elian et al. 2011)

When several implants are used for oral rehabilitation, the interimplant distance can have a substantial influence on bone remodeling since it has been shown that implants placed too close together can reduce the height of the inter-implant bone crest. Evidence suggests that an inter-implant distance < 3 mm can lead to increased bone loss (Tarnow et al. 2000; Kuperschmidt et al. 2007). However, some clinical situations may require the placement of implants with an inter-implant distance of < 3 mm to allow optimal positioning. This investigation, therefore, intended to evaluate bone control design in terms of bone loss and soft tissue response to Straumann® Bone Level implants Fig. 2: Radiographic crestal bone change measurements.

at different inter-implant distances (2 or 3 mm). Materials and methods Seventy-two Straumann® Bone Level implants (SLActive ®,

The inter-implant distance was analyzed with respect to the fol-

Ø 4.1 mm, 8 mm length) were placed in the mandibles of 12

lowing parameters (Fig. 3): gingival height, biological width,

minipigs with an inter-implant distance of 3 mm on one side and

connective tissue contact and sulcus depth.

ment placement to allow transmucosal healing (Fig. 1).

2 mm Group B 2 mm

P M

M A

3 mm Group A 3 mm

aJE CTC

pre-clinical studies

2 mm on the contralateral side, followed by immediate abut-

cBI

Fig. 3: Soft tissue response analysis. GH = Gingival height; BW = biological width; CTC = connective tissue contact; SD = sulcus depth; cBI = Crestal bone to implant level.

Results Radiological bone change Fig. 1: Group A: 3 implants with a interproximal distance of 3 mm; Group B: 3 implants with a interproximal distance of 2 mm. P = posterior, M = middle, A = anterior.

There was no statistically significant difference between the two groups regarding the inter-implant bone change after 8 weeks (Fig. 4).

Standardized radiographs were taken immediately after surgery

Histomorphometric analysis

and 8 weeks after implantation (time of termination) to measure

The results showed that the mean overall BIC was not significant-

mesial and distal inter-implant bone change (Fig. 2). Histologi-

ly different between the two groups (74 ± 15 % and 75 ± 18 %

cal analyses were conducted on non-decalcified sections. In or-

in the 2 mm and 3 mm groups, respectively), as displayed in

der to measure the osseointegration behavior of the two groups,

Fig. 5. There was no statistically significant difference between

the bone-to-implant contact (BIC) was measured.

the two groups regarding the histomorphometric results.

Soft tissue assessment Measurements were made in the inter-implant areas. For all soft tissue parameters, no statistically significant difference was found between the groups (Tab. 1).

Fig. 4: Radiographic pictures of the test set-up at implant insertion (left) and after 8 weeks (right). The data show a slight bone gain in the test group and no bone change in the control group.

Group

Mean bone change

2 mm group

0.1 mm ± 0.9 mm

3 mm group

0.0 mm ± 0.6 mm

Inter-implant distance

2 mm

3 mm

Bone width

3.8 ± 0.5

4.0 ± 1.2

Gingival height

4.2 ±1.2

4.5 ± 1.3

Connective tissue contact

1.7 ± 1.0

1.1 ± 1.1

Sulcus depth

0.5 ± 0.5

0.6 ± 0.5

Key findings and conclusion

pre-clinical studies

(1) In this study, no statistically significant difference between inter-implant distance of 2 mm and 3 mm was found for any inves-

100 %

tigated parameters. (2) BIC reached approximately 75 %. (3)

80 %

Soft tissue remained stable. The results of this study confirm that the Bone Control Design™ of the Straumann® Bone Level im-

60 %

plant provides the required level of bone maintenance, even in

40 %

challenging situations.

20 % 0% 2 mm

3 mm

Fig. 5: Histomorphometric analysis of the bone-to-implant contact did not show any statistically significant difference between the 2 mm and 3 mm groups.

Conclusions on pre-clinical research ▪▪ Straumann® Bone Level implants with a hybrid self-tapping body design show a higher primary stability compared to Tissue Level implant design (Toyoshima et al. 2011).

▪▪ Straumann® Bone Level implants with a SLActive ® Surface showed a higher removal torque compared to OsseoSpeed™, Tapered Screw Vent ®, ScrewPlant™ and Osstem™ (Gottlow et al. 2010).

▪▪ Pre-clinical animal studies show excellent and predictable bone preservation with Straumann® Bone Level implants placed at different heights both before and after loading (Jung et al. 2008).

▪▪ Straumann® Bone Level implants with non-matching implant and abutment diameters (platform switching) can be either submerged or non-submerged with no adverse effect on bone maintenance (Cochran et al. 1997; Hermann et al. 1997; Schwarz et al. 2008).

▪▪ Excellent bone preservation and soft tissue response have been shown even with 2 mm inter-implant distances (Elian et al. 2011).

pre-clinical studies

when Straumann® Bone Level implants were placed adjacent to each other,

3. Clinical studies

After extensive pre-clinical assessments of Bone Level implant performance and safety, clinical studies were initiated. The main goal of all clinical studies was to confirm in patients that the StraumannÂŽ Bone Level implant, due to its Bone Control Designâ&#x201E;˘, shows minimal bone remodeling, excellent soft tissue response, and high success and

Clinical studies

survival rates which lead to long-lasting esthetic outcomes.

Early implant placement in the esthetic zone (SMILE I: 12 months) D. Buser, S. Halbritter, C. Hart, M.M. Bornstein, L. Grütter, V. Chappuis, U.C. Belser. Early implant placement with simultaneous guided bone regeneration following single-tooth extraction in the esthetic zone: 12-month results of a prospective study with 20 consecutive patients. J Periodontol 2009;80(1):152–162. (Buser et al. 2009)

SMILE I: 12-month follow-up results

Results

Early implant placement following extraction of a single tooth is

All implants were successfully integrated at 12 months, with

a procedure used by many clinicians in the maxillary anterior

healthy peri-implant soft tissues. The implants fulfilled strict suc-

zone (Chen et al. 2004), but there is a lack of documentation

cess criteria (Buser et al. 1990), and the results were in line with

on esthetic outcomes. When esthetic results have been report-

those from other prospective studies with the same parameters

ed, mucosal recessions have been observed (Chen et al. 2007).

(Buser et al. 1990; Behneke et al. 2000; Behneke et al. 2000;

The aim of this study, therefore, was to prospectively investigate

Weber et al. 2000; Bornstein et al. 2005).

esthetic outcomes of early implant placement in single-tooth extraction sockets in the esthetic zone with Straumann® Bone Level

The mean mPLI, mSBI and PD values at 12 months were 0.36,

implants.

0.21, and 4.43 mm, respectively (Tab. 1). A wide KM band was seen at 3 months, which remained stable at 6 and

Materials and methods

12 months (Tab. 1). Mean DIB values at 3, 6, and 12 months

A total of 20 patients requiring single-tooth replacement in the

were 0.09, 0.14, and 0.18 mm, respectively (Tab. 1). The radio-

anterior maxilla participated in the study. After tooth extraction,

graphic analysis indicated that 15 of 20 implants showed mini-

the socket was allowed to heal for 4–8 weeks. The Bone Level

mal bone resorption (Fig. 2), and only one implant showed

implants were subsequently placed and sealed with healing

bone loss > 0.5 mm with minor mucosal recession of 0.5–

caps. Simultaneous contour augmentation was performed using

1.0 mm. The mean DIM values at 12 months were –6.68,

guided bone regeneration (GBR) with bovine bone mineral and

–6.00, –3.53, and –3.84 mm for mesial, distal, facial and oral,

a collagen membrane (Fig. 1). Reopening was performed 8–12

respectively. Predictable contour augmentation with an inorgan-

weeks later (Day 0). Within 7 days, provisional crowns were

ic bovine bone mineral, therefore, showed a low risk of mucosal

placed, which were gradually enlarged, if necessary, to opti-

recession. (Lindeboom et al. 2006; Chen et al. 2007; Evans/

mize soft tissue contours. Final screw-retained all-ceramic resto-

Chen 2008).

rations were placed after 6 months.

6 mos.

12 mos.

mPLI

0.08 ± 0.24

0.08 ± 0.20

0.36 ± 0.33

mSBI

0.26 ± 0.29

0.16 ± 0.23

0.21 ± 0.17

3.69 ± 0.62

3.75 ± 0.46

4.43 ± 0.57

4.06 ± 1.43

4.10 ± 1.41

4.50 ± 1.54

DIB

0.09 ± 0.16

0.14 ± 0.25

0.18 ± 0.20

Tab. 1: Clinical and radiographic parameters at 3, 6 and 12 months.

Clinical studies

3 mos.

Fig. 1: Occlusal view following implant placement with a 2-wall p eri-implant defect, favorable for predictable GBR.

The parameters measured were: modified plaque index (mPLI), modified sulcus bleeding index (mSBI), probing depth (PD), width of keratinized mucosa (KM), distance from mucosal margin to implant shoulder, distance from implant shoulder to first bone-to-implant contact (DIB), mid-facial height of implant crown and contralateral tooth, pink esthetic score, and white esthetic score. 27

The mean pink and white esthetic scores were 8.10 and 8.65, 5%

respectively (total score = 16.75) indicating good esthetic outcomes. The maximum for both pink and white esthetic scores is 10, and the threshold for clinical acceptability is 6/10 for

15%

each index. Conclusions (1) Good esthetic and clinical results were seen over 12 months. (2) The risk of mucosal recession was low. (3) Strict success criteria were fulfilled resulting in 100 % success and survival rates at

Bone loss 80%

0.0–0.3 mm 0.3–0.6 mm 0.6–0.9 mm

12 months. (4) Minimal crestal bone resorption was demonstrat-

Clinical studies

ed. (5) The majority of patients showed < 0.3 mm bone loss.

Fig. 2: The majority of patients (80 %) showed < 0.3 mm bone loss.

Early implant placement in the esthetic zone (SMILE I: 36 months) D. Buser, J. Wittneben, M.M. Bornstein, L. Grütter, V. Chappuis, U.C. Belser. Stability of contour augmentation and esthetic outcomes of implant-supported single crowns in the esthetic zone: 3-year results of a prospective study with early implant placement postextraction. J Periodontol 2011;82(3):342–349. (Buser et al. 2011)

SMILE I: 36-month follow-up results

Standard soft tissue parameters

Early implant placement following the extraction of a single

Standard soft tissue parameters, such as mPLI, mSBI, PD, and

tooth is a procedure used by many clinicians in the maxillary an-

KM were assessed after 3, 6, 12, and 36 months from baseline.

terior zone (Hammerle et al. 2004), but there is a lack of docu-

These parameters were assessed with the crown in place. Mean

mentation on the esthetic outcomes. When esthetic results have

mPLI and mSBI values at 36 months were 0.40 and 0.20 re-

been reported, mucosal recessions have been observed (Chen

spectively (Tab. 1). The mean PD value increased from 3.69 mm

et al. 2007). The aim of this study was, therefore, to prospec-

at the 3-month visit to 4.00 mm at the 36-month visit. However,

tively investigate esthetic outcomes of early implant placement

the change was not statistically significant. A wide KM band

in single-tooth extraction sockets in the esthetic zone with Strau-

was seen at 3 months, which remained stable at the following

mann® Bone Level implants.

points in time (Tab. 1).

Materials and methods

3 mos.

6 mos.

12 mos.

36 mos.

mPLI

0.08 ± 0.24

0.08 ± 0.20

0.36 ± 0.33

0.40 ± 0.27

traction, the socket was allowed to heal for 4–8 weeks. Bone

mSBI

0.26 ± 0.29

0.16 ± 0.23

0.21 ± 0.17

0.20 ± 0.20

Level implants (Ø 4.1 mm SLActive ) were subsequently placed

3.69 ± 0.62

3.75 ± 0.46

4.43 ± 0.57

4.00 ± 0.56

and sealed with healing caps, with simultaneous contour

4.06 ± 1.43

4.10 ± 1.41

4.50 ± 1.54

4.10 ± 1.17

A total of 20 patients requiring single-tooth replacement in the anterior maxilla participated in the study. After flapless tooth ex®

augmentation using locally harvested autogenous bone with inorganic bovine bone mineral and a collagen membrane. Reopening was performed 8–12 weeks later (Day 0). Within

Tab. 1: Mean and standard deviation values of the standard soft tissue parameters over the 3-year follow-up period. The displayed values of KM and PD are in mm.

7 days, provisional crowns were placed, which were gradually enlarged, if necessary, to optimize soft tissue contours. Final

Radiographic evaluation/DIB values

screw-retained all-ceramic restorations were placed after

Periapical radiographs were taken from baseline at every visit.

6 months.

The distance from implant shoulder to the first BIC was assessed

The patients were recalled for follow-up visits at 12, 24, and

were observed: DIB increased from 3 to 6 and to 12 months

36 months. During these visits, various parameters were as-

with values of 0.09 mm, 0.14 mm, and 0.18 mm, respectively.

sessed, such as:

The mean value remained stable at 0.18 mm thereafter until

▪▪ Modified plaque index (mPLI) ▪▪ Modified sulcus bleeding index (mSBI) ▪▪ Probing depth (PD) ▪▪ Width of keratinized mucosa (KM) ▪▪ Distance from implant shoulder to first bone-to-implant

36 months (Fig. 1).

(DIB). At baseline the mean DIB was 0 mm. Remodeling p atterns

▪▪ Pink esthetic score (PES) (Belser et al. 2009) ▪▪ White esthetic score (WES) (Belser et al. 2009) For all measurements, the day of reopening was set as baseline (Day 0). Results All 20 implants achieved and maintained successful tissue integration at the 3-year follow-up visits fulfilling strict success crite-

Clinical studies

contact (DIB)

0.2 0.1 0 – 0.1 – 0.2 – 0.3 – 0.4 – 0.5 0 mo.

3 mos.

6 mos.

12 mos.

24 mos.

36 mos.

Fig. 1: Crestal bone change displayed by the mean DIB value (in mm) showing a remodeling pattern in the first 12 months and stable bone for the following months.

ria (Buser et al. 2011).

Radiographic analysis of crestal bone showed that 18 patients

Key findings and conclusion

had a bone loss of 0.5 mm or less after 3 years.

(1) Strict success and survival criteria were fulfilled resulting in 100 % success and survival rates at 36 months. (2) Minimal

Esthetic parameters

crestal bone resorption was demonstrated. (3) Stable crestal

The maximum for both pink and white esthetic scores is 10, and

bone after 12 months was shown. (4) Good esthetic and clini-

the threshold for clinical acceptability is 6/10 for each index.

cal results were seen at 12 and 36 months.

The mean PES and WES scores (Belser et al. 2009) remained stable between 12 and 36 months with values of 8.10 and

In the present study, Bone Level implants were used in a

8.65, respectively (total score of 16.75) indicating a favorable

p latform-switching design. This design has gained a great 足

esthetic outcome (Tab. 2).

deal of attention in recent years because it is believed to be associated with minimal bone resorption at the crestal level 36 mos.

Mean PES

8.1

Mean WES

8.65

from the day of loading to the 3-year follow-up leading

Total

16.75

to high performance and high esthetic outcomes. (Buser et

Clinical studies

Tab. 2: The esthetic parameters remained stable at high values between 12 and 36 months.

during functional loading (Lazzara/Porter 2006; Atieh et

12 mos.

al. 2010). The present study confirms this hypothesis as the 20 implants showed an average bone loss of only 0.18 mm

al. 2011).

Bone maintenance around Bone Level implants in submerged and non-submerged techniques C.H. Hämmerle, R.E. Jung, M. Sanz, S. Chen, W.C. Martin, J. Jackowski; On behalf of this multicentre study group, C.J. Ivanoff, L. Cordaro, J. Ganeles, D. Weingart, J. Wiltfang, M. Gahlert. Submerged and transmucosal healing yield the same clinical outcomes with two-piece implants in the anterior maxilla and mandible: interim 1-year results of a randomized, controlled, clinical trial. Clin Oral Implants Res 2012;23(2):211–219. (Hammerle et al. 2012)

0.5

Surgical procedure and implant design both influence esthetic outcomes. For example, a submerged technique may be pre-

0.0

ferred to establish esthetics and function in anterior sites, and

prove the esthetics of the restorations. The marginal bone

Baseline implant placement

–1.0

change over time is another important factor (Hermann et al. 2001b), with a historical success criterion meaning a bone loss

–0.3

–0.5

implants where the metallic shoulder is reduced may help to im-

–0.47 Final prosthesis

–1.5

of no more than 1.5 mm in the first year and < 0.2 mm annually

–2.0

thereafter (Albrektsson et al. 1986). This investigation was designed to evaluate the amount of bone

month mean bone loss (mm)

SMILE II: 12-month follow-up results

Fig. 1: Mean bone level change from baseline at 6 and 12 months.

level change with submerged and transmucosal healing and to assess any difference in bone level change between the two procedures with Straumann® Bone Level SLActive ® Implants.

tissue recession, implant survival and success as well as prosthe-

> +1.5 to 2.0 mm

> +1.0 to 1.5 mm

Fig. 2: Percentage of implants within different categories of bone level change.

Results The intention-to-treat (ITT) population for the 1-year results in-

12 months the mean change in bone level was –0.47 ± 0.64 mm

cluded 127 patients (60 and 67 in the transmucosal and sub-

(–0.47 ± 0.64 mm and –0.48 ± 0.65 mm for the submerged

merged groups, respectively, with a mean age of 45.5 and

and transmucosal groups, respectively) (Fig. 1). There was, there-

47.3 years, respectively). Based on the 12-month ITT population

fore, no significant difference in bone level change between the

data, the mean change in bone level after 6 months was –0.30

two groups. Almost two thirds of implants (64.8 %) showed

± 0.47 mm (–0.32 ± 0.47 mm and –0.29 ± 0.35 mm for the

< 0.5 mm bone loss over 12 months (Fig. 2). The implant survival

submerged and transmucosal groups, respectively), while after

and success rate was 99.2 %.

Clinical studies

sis success.

> +0.5 to 1.0 mm

intended for up to 5 years. Secondary parameters included soft

> –0.0 to +0.5 mm

placement (6 months) and 12 months, with an annual follow-up

> –0.5 to 0.0 mm

line), provisional placement (approx. 14 weeks), final crown

0 > –1.0 to –0.5 mm

measured by standardized radiographs taken at surgery (base-

> –1.5 to –1.0 mm

26 weeks. The primary parameter was change in bone level

> –2.0 to –1.5 mm

14 weeks, and the final reconstruction was placed after

> –2.5 to –2.0 mm

in 7 countries. A temporary crown was placed between 8 and

> –3.0 to –2.5 mm

mandible) were placed in a total of 146 patients in 12 centers

> –3.0 mm

Implants to replace single teeth in the anterior region (maxilla or

Baseline to 12 months

Materials and methods

The patient satisfaction with the final prosthesis was extremely

a more acceptable bone loss for modern implant systems would

high; 99 % of patients reported their level of satisfaction as ex-

be 0.5 mm over 5 years. However, many of the studies on

cellent or good (Fig. 3).

which this suggestion is based use placement of the temporary or final prosthesis rather than placement of the implant as the baseline measurement for bone level change (Engquist et al.

General patient satisfaction with final prosthesis (all patients at 1-year visit)

fair 1%

2002). Studies that use implant placement as the baseline measurement for bone level change have shown relevant bone loss before loading (Engquist et al. 2002; Astrand et al. 2004;

poor 0 %

Astrand et al. 2004), therefore, using prosthesis placement as the baseline may give an inaccurate reflection of the real amount

good 22 %

of bone loss (Cooper et al. 2001; De Bruyn et al. 2008). A more accurate picture may be possible by measuring bone levels at implant placement and at regular intervals thereafter (Fig. 3). The knowledge of the amount of bone level change to expect has huge clinical relevance in treatment planning to excellent 77 %

achieve an optimum esthetic outcome, for example, unexpected bone loss can cause substantial soft tissue recession resulting in an esthetic failure.

Fig. 3: General patient satisfaction with final prosthesis at 12 months.

To summarize

▪▪ Marginal bone level change was small and not significantly Key findings and conclusion Traditional implant success criteria include an acceptable bone loss of ≤ 1.0 mm in the first year and < 0.2 mm annually thereafter (Albrektsson et al. 1986). Recently, however, there have

Clinical studies

been suggestions for these criteria to be revised indicating that

different between submerged and transmucosal implants.

▪▪ Extremely high survival and success rates were observed (99.2 % for both).

▪▪ Patient satisfaction with the outcome was extremely high (99 %).

Bone maintenance around Bone Level implants in submerged and non-submerged techniques L. Cordaro, S. Chen, M. Sanz, J. Wiltfang, D. Weingart, W.C. Martin, J. Ganeles, C.-J. Ivanoff, J. Jackowski, M. Gahlert, R. Jung. Submerged vs. non-submerged healing of implants for single-tooth replacement in the esthetic zone. Results from a multicenter RCT. European Association for Osseointegration 19 th Annual Scientific Meeting, October 6–9 2010, Glasgow, UK; Abs. 053. (Cordaro et al. 2010)

SMILE II: 24-month follow-up results

Radiographic evaluation/crestal bone change

Both surgical procedure and implant design influence esthetic

Periapical radiographs were taken at surgery (baseline) and

outcomes. For example, a submerged technique may be pre-

6, 12, and 24 months post-surgery to evaluate crestal bone

ferred to establish esthetics and function in anterior sites, and

change. Mean crestal bone change showed remodeling pat-

implants where the metallic shoulder is reduced may help to im-

terns at 6 and 12 months with mean values of –0.31 mm and

prove the esthetics of the restorations. The marginal bone

–0.46 mm for the entire ITT population. From 12 to 24 months,

change over time is another important factor (Hermann et al.

there was a minor bone change of –0.01 mm indicating stable

2001a; Hermann et al. 2001b; Hermann et al. 2001c), with a

bone. Comparing the crestal bone change of the two groups,

historical success criterion meaning bone loss of no more than

no statistically significant difference was found, and the bone

1.5 mm in the first year and < 0.2 mm annually thereafter (Al-

change pattern was similar for both groups (Fig. 1).

brektsson et al. 1986). This investigation was designed to evaluate the amount of bone

baseline

level change with submerged and transmucosal healing and to procedures with Straumann® Bone Level SLActive ® implants.

–0.2

Materials and methods

–0.4

terior maxilla or mandible were placed in a total of 146 patients in 12 centers in 7 countries. A temporary crown was placed be-

–0.8 –1

after 26 weeks. The primary parameter was the evaluation of taken at various steps. Secondary parameters included soft tissue parameters, implant success and survival rate, as well as

after 24 mos.

–0.6

tween 8 and 14 weeks, and the final reconstruction was placed change in bone level measured by standardized radiographs

after 12 mos.

assess any difference in bone level change between the two

Implants (Ø 4.1 mm SLActive ®) to replace single teeth in the an-

after 6 mos.

submerged

transmucosal

Fig. 1: Percentage of implants within different categories of bone level change.

success rate of prosthetic restorations. Control: submucosal healFrequency analysis of crestal bone change did not show any statistically significant difference between the two groups The patients were recalled for several follow-up visits at various

(Fig. 2).

points in time. During these visits, various parameters were assessed, such as:

Soft tissue parameters

▪▪ Probing pocket depth (PPD) ▪▪ Clinical attachment level (CAL) ▪▪ Crestal bone change ▪▪ Patient satisfaction

The mean CAL and PPD values remained stable between screen-

Clinical studies

ing (SMH). Test: transmucosal healing (TMH).

ing and 2-year follow-up for both groups (SMH and TMH) as displayed in Tab. 1. When evaluating the soft tissue parameters at the 2-year visit,

Results

no statistically significant difference between the test and control

The intention-to-treat (ITT) population for the 2-year results includ-

groups was found.

ed 120 patients (58 patients TMH group, 62 patients SMH group). One implant was lost at placement of the final prosthesis

Patient feedback

(6 months after surgery). Thus, the survival rate was 99.2 %.

Patients were asked about general treatment satisfaction with their final prosthesis. In nearly 80 % of the cases, the patients rated their solution as excellent. 33

40 %

Conclusions

30 %

▪▪ High survival (99.2 %) and success rates (99.3 %) ▪▪ There was no statistically significant difference between the control and test groups (submucosal and transmucosal groups), therefore, supporting Bone Level implants for both

20 %

healing types

▪▪ Minimal crestal bone change was observed 24 months after 10 %

implant placement

▪▪ Stable crestal bone between 12 and 24 months was observed (–0.01 mm)

0% more than 1 mm

from 0.5 mm to 1.0 mm

from 0.0 mm to 0.5 mm

from –0.5 mm to 0 mm

from –0.5 mm to –1 mm

less than –1 mm

submerged transmucosal

Fig. 2: In both groups, a positive bone change or a negative change up to –0.5 mm was observed in more than 80 % of the cases.

CAL

PPD

Group

Screening

2-year FU

SMH

2.6 ± 1.1

2.6 ± 1.0

TMH

2.5 ± 0.9

2.6 ± 1.1

SMH

2.3 ± 0.5

2.4 ± 0.6

TMH

2.1 ± 0.5

2.4 ± 0.6

Clinical studies

Tab. 1: Soft tissue parameters (in mm, mean ± standard deviation) at screening and 2-year follow-up visit.

▪▪ Soft tissue parameters did not reveal any substantial changes between screening and 24-month follow-up

▪▪ High patient satisfaction

Conclusions on clinical studies Straumann® Bone Level implants:

▪▪ Facilitate highly esthetic results due to very good crestal bone preservation leading to stable soft tissue

▪▪ Show a high success rate (99.3 –100 %) (Buser et al. 2011) and high patient satisfaction (Cordaro et al. 2010; Hammerle et al. 2012)

▪▪ Can be successfully used in a wide range of indications ▪▪ Have levels of performance confirmed in a large-scale trial in a private practice setting

Clinical studies

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OsseoSpeed™ and Astra Tech™ are registered trademarks of Astra Tech AB, Sweden. Tapered Screw Vent® and Zimmer® are registered trademarks of Zimmer Dental Inc USA. ScrewPlant™ and Implant Direct® are registered trademarks of Implant Direct, USA. Osstem™ is a trademark of Osstem Company Ltd., Seoul, Korea. GS II Fixture is a brand of Osstem Company Ltd., Seoul, Korea. © Institut Straumann AG, 2012. All rights reserved. Straumann® and/or other trademarks and logos from Straumann® mentioned herein are the trademarks or registered trademarks of Straumann Holding AG and/or its affiliates. All rights reserved.

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