INDIRECT BONDING
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INDIAN DENTAL ACADEMY Leader in continuing dental education
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Introduction Tooth movement is made possible by an orthodontist by applying an optimal force. Archwires,loops,springs,elastics, etcrigid attachment-bracket www.indiandentalacademy.com
Bands or bonds Bonding – several advantages and disadvantages
Advantages -
1.esthetic superiority 2.faster and simpler 3.less discomfort to the patient 4.arch length is not increased www.indiandentalacademy.com
Bonds are more hygienic than bands Mesiodistal enamel reduction is possible Interproximal areas are accessible for comp buildups Caries risk under loose bands is eliminated
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No band spaces are left behind No large inventory of bands Lingual brackets, invisible braces Brackets may be recycled further reducing cost
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Disadvantages
Weaker attachment Gingival problems The protection against well contoured bands is absent Rebonding a loose bracket Debonding is more time consuming
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Review
Acid etch bonding technique Acid pretreatment-85% phosphoric acid-1955-Buonocore 1965-epoxy resin-Newman 1968-smith poly acrylate 1970-several articles www.indiandentalacademy.com
The most widely used resin, commonly referred to as Bowen’s resin was designed to improve bond strength and increase dimensional stability by cross linking www.indiandentalacademy.com
The indirect bonding technique was introduced by Dr. Silverman and Cohen in 1972 AJO www.indiandentalacademy.com
Types of bonding 1.Indirect bonding 2.Direct bonding a. chemical cured b.light cured composite c.glass ionomer cement www.indiandentalacademy.com
With the indirect bonding technique, brackets fixed to the tooth in the working casts and then transferred to the patients mouth with the help of an impression tray which is usually made of silicone www.indiandentalacademy.com
The bonding procedure in short 1. cleaning 2. enamel conditioning 3. sealing 4. bonding a. transfer b. positioning c. fitting d. removal of excess www.indiandentalacademy.com
Cleaning pumice- plaque and organic pellicle rubber cup or polishing brush bristle brush – more effective but has certain disadvantages www.indiandentalacademy.com
Enamel conditioning A. moisture control
After pumice-salivary control and dry working field 1.cheek retractors 2.saliva ejectors 3.tongue guards with bite blocks 4.salivary duct obstructers [dri-angles –parotid] www.indiandentalacademy.com
5. Cotton or gauze rolls 6. antisialogoguesbanthine,probanthine, atropine sulphate etc ..both tablets and injections ..PB inj are no longer advised ..antisialogogues are generally not www.indiandentalacademy.com
banthine tab-50mgs/100lb-15 minutes before bonding only under supervision of the patients physician contact lenses should be removed-until next day
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B.enamel pretreatment Conditioning solution[37% phosphoric acid for 15-60 sec] Etchant rinsed off Salivary contamination-not allowed. If it occurs water spray or re-etch for a few seconds; the patient must not rinse www.indiandentalacademy.com
Next the teeth are thoroughly dried with moisture and oil free source to obtain the well known dull, frosty appearance www.indiandentalacademy.com
Good bond strength is dependent on 1.avoiding moisture contamination 2.achieving undisturbed setting of bonding adhesive 3.use of a strong adhesive www.indiandentalacademy.com
Sealing Nothing but an intermediate resin Teeth dry-thin layer of sealant Foam pellet or brush with a single gingivo- incisal stroke The sealant coating should be thin and even www.indiandentalacademy.com
Bonding The easiest method of bonding.. 1. transfer 2. positioning 3. fitting 4. removal of excess www.indiandentalacademy.com
a slight bit of excess is necessary excess adhesive should be removed excess adhesive when not removed-discolored the first three procedures are the same for direct and indirect bonding techniques
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Indirect bonding.. www.indiandentalacademy.com
Originally described by Dr. Silverman and Cohen several techniques-the brackets are attached to the teeth on patients model, transferred to the mouth with some sort of tray to which the brackets get embedded and then bonded simultaneously www.indiandentalacademy.com
The clinical procedure The techniques differ ..the way brackets are attached to the model ..type of transfer tray ..adhesive or sealant used ..the way transfer is removed www.indiandentalacademy.com
An over view of the indirect bonding technique a. Take an impression and pour with stone. Model-dry. Long axis and occlusal height b. Select brackets c. Apply water soluble adhesive d. Position the brackets www.indiandentalacademy.com
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e. Mix putty silicone and press it onto the cemented brackets f. Immerse model and tray in hot water. Remove any remaining adhesive g. Trim the silicone tray and mark the midline h. Prepare the patients teeth i. Load adhesive-bracket base www.indiandentalacademy.com
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j. Seat the tray on the prepared arch-3 minutes k.Remove tray after 10 min. tray must be cut longitudinally or transversely l. Complete bonding by careful removal of excessive flash www.indiandentalacademy.com
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Modifications Several methods – bonding resins, sticky wax etc Dr. Michael.D.Simmons-1978April-JCO-caramel candy softened and preloaded in syringe. Small amount of caramel is warmed to approx 500c –loaded 0 preloaded syringe- 50 c-5min www.indiandentalacademy.com
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A small amount is squeezed onto each tooth to be bonded. The brackets are then held with cotton pliers warmed slightly in Bunsen burner and then placed on the teeth. Rest of the procedure is similar Disadvantage of sticky wax. Advantage of caramel candy www.indiandentalacademy.com
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2.Since one of the major difficulties with indirect bonding‌ double tray techniqueElliott.M.Moskowitz and Douglas Knight-1996 may JCO Thermal cured composite [unlimited working time] and vinyl polysiloxane [flexible but highly accurate under tray] www.indiandentalacademy.com
Apply thermacure composite to the mesh pad of each bracket-cast. Cast in heated oven -15 min at o 325 F. After cooling remove. Apply vinyl polysiloxane over thermally cured brackets. Adapt the vacuum formed Essix clear thermoplastic material over the cast, brackets and under tray comp. www.indiandentalacademy.com
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Chair side bonding procedure. 1. Lightly abrade adhesivediamond bur or simply scrape 2. Isolate, etch, rinse and dry as usual. 3. Apply bonding agent-tooth and adhesive –bracket bases and www.indiandentalacademy.com
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4. Remove the clear over tray. 5. Tease the flexible under trayexplorer or scaler without dislodging the brackets. Advantages‌ The under trays are accurate, stable and compact and will not dislodge the brackets from teeth when removed www.indiandentalacademy.com
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3. Light cured indirect bonding. JCO-1998-Aug-Michael Read Transfer tray-silicone based, addition cured elastomer [Memosil]stiff enough but easily removed . 1. Coat labial surface of teeth with thin layer of Poly vinyl acetate www.indiandentalacademy.com
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2. Brush a thin layer of unfilled resin onto each bracket base-light cure it for 30 sec. 3. Add the filled composite to bracket bases-brackets on the casts. 4. Cure each bracket-30 sec from occlusal and 30 sec form gingival. 5. Adapt the transfer tray. www.indiandentalacademy.com
6. Soak the tray in cold water for 20 min. 7. Etch the teeth to be bonded as usual. Paint thin layer of unfilled resin over the etched enamel and over the cured composite 8. Place the transfer tray in the mouth and light cure each tooth for 30 sec. www.indiandentalacademy.com
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4.Thermal cured, fluoride releasing indirect bonding system. JCO-1998-Feb-Sinha,Nanda Modification of previously described IB with Therma cure. Failure to remove excess adhesive-accumulation of plaque. Even when excess plaque is reasonably removed-deposits . www.indiandentalacademy.com
The only modification in this technique is we add Maxicure sealants A and B. This sealant contains hydrofluoric acid in its monomer thereby preventing caries www.indiandentalacademy.com
5. Adhesive precoated brackets JCO-1993-March by Ronald B Cooper. Except for the APC brackets the rest of the procedure is similar www.indiandentalacademy.com
6. Sondhi indirect adhesive AJO-April-1999 why a new adhesive A new resin with higher viscosity [fine particle fumed silica filler] Setting time-30 sec Complete curing in 2 min www.indiandentalacademy.com
The lab procedure Working models Separating medium-1 hour APC brackets-removed directly from the sealed blister If non coated bracketsTransbond XT light cured adhesiveplaced on mesh pad www.indiandentalacademy.com
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Remove the excess cement. Cure the resin Significant undercut areas are blocked with wax. Bonding trays are formed-either double tray technique or with silicone transfer material. Cure it again to ensure that any uncured resin is cured www.indiandentalacademy.com
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The bonding procedure Initial preparations Micro-etching unit – sand blast Contamination of custom adhesive bases –acetone and air dry MIP is optional Sondhi Indirect adhesive – resin A[tooth surface] and Resin B[resin pads] www.indiandentalacademy.com
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Position the tray over the teeth – equal pressure- 30 sec- 2 min Remove Tray with scaler- from lingual to buccal Repeat the procedure for the opposite arch www.indiandentalacademy.com
Main indication lingual Early 1970s – Dr Craven Kurz – Assistant Professor of occlusion and gnathology Plastic lee fischer brackets –ant. and metal for post. Shearing force – debonding Uncomfortable to the tongue www.indiandentalacademy.com
Turning point – ant. Inclined plane – shearing force to intrusive force – intrusive and labial
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Difficulties and modifications Tissue irritation and speech earlier vs current brackets smooth exteriors – normal activity Gingival impingement earlier-broad bonding baseadequate oral hygiene,self cleansing-compromised
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The bases now-incisally and mesio distally wide Additionally gingival hooks were redesigned so that they are shorter and also away from the gingiva www.indiandentalacademy.com
Occlusal interference Predominant problem-shearing force- upper ant brackets Redesigned with inclined plane Location of inclined plane..
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Base pad adaptation Accurate contour of base pad not only improves the retentive capability but also the accuracy of bracket placement – quality of treatment www.indiandentalacademy.com
Appliance prescription Early 1970s – Andrews – straight wire In-out varied dramatically-to adjust this purely by bracket design ? First order bends – where?
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Wire placement Access for wire placement is limited from lingual aspect. Redesigned – widening the mesial opening www.indiandentalacademy.com
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Gingival hooks They are an integral part of lingual appliance therapy. Original hooks were larger-redesigned – smaller and away from gingival margin www.indiandentalacademy.com
Generation of brackets First generation - 1976 Flat maxillary Occlusal bite plane. Premolar brackets were low profile. No hooks on any bracket www.indiandentalacademy.com
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Second generation- 1980. Hooks were added to all canine brackets. Third generation – 1981. Hooks were added to all anterior and premolar brackets www.indiandentalacademy.com
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Fourth generation – 1982-84. Low profile anterior bite plane. Hooks were optional – depending upon treatment plan and hygiene requirements www.indiandentalacademy.com
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Fifth generation – 1985-86 Inclined plane – more pronounced Greater labial torque – max incisors Hooks were optional Sheath for TPA was available Canine inclined plane-bi beveled
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Sixth generation–1987–90. Inclined plane – square shaped TPA sheath was optional Hinge cap attachment for molar
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Seventh generation-1990 0nwards
Inclined plane is heart shaped Premolar brackets – wider mesio distally with shorter hooks All hooks have greater recess – ease of ligation
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Situations where lingual therapy is advantageous 1. Intrusion. 2. Max arch expansion . 3. Max molar distalisation www.indiandentalacademy.com
Intrusion Brackets closer to c res. Intrusive forces closer to c res. Bite plane effect – active intrusion on ant and passive extrusion of post www.indiandentalacademy.com
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Maxillary arch expansion although not clearly understood,clinically‌ possible reasons-1. Centrifugal force 2. Thickness of brackets 3. Shorter IB span could also be a possible cause www.indiandentalacademy.com
Maxillary molar distalisation. Lingual attachments are closer to the c res.of the molar – which is found corresponding to the palatal root of molar www.indiandentalacademy.com
Laboratory techniques. 1. CLASS system. 2. TARG system. 3. HIRO system. www.indiandentalacademy.com
The CLASS system 1. Accurate impressions – die stone. 2. Duplicate the cast . 3. Prepare a diagnostic set-up – arch form,ant. Tip torque, alignment etc 4. Clean the lingual surface – apply separating medium www.indiandentalacademy.com
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6. Mount the model on model holder with Occlusal plane parallel to horizontal reference plane. 7. Brackets are attached to the set-up cast – two part heavy body composite. 8. Transfer brackets to malocclusion cast – light cured www.indiandentalacademy.com
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9. Brackets removed from set-up model and attached to malocclusion model – water soluble adhesive. 10. Hot oven for 1 hour. 11. Remove the light cured resin and fabricate transfer – biostar machine www.indiandentalacademy.com
12. Place the cast in warm water for 30 min – remove the tray 13. Abrade the composite slightly. 14. Trays are labeled and placed in a clean sealed plastic bag www.indiandentalacademy.com
The TARG system. Torque angulation reference guide – ORMCO 1984. Capable of positioning the brackets at specific heights. Consists of a torque gauge middle of labial surface. A torque blade is used to orient the brackets www.indiandentalacademy.com
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The horizontal blade of TARG gauge – bracket slot – moved towards varnished model. The gap – packed with a filled resin – custom made bracket base which accurately fits the lingual surface is made. Transfer tray fabricated www.indiandentalacademy.com
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Advantages Permits more accurate placement of brackets Decreases chair side time Less patient discomfort Esthetically more pleasing Incidence of caries is less
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Avoiding band fitting on posterior teeth ď Ž Improved ability to bond posterior teeth ď Ž
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Disadvantages Technique sensitive Additional set of impressions needed Posterior attachments more likely to fail if the patient chews ice etc
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Removal of adhesive is more difficult and time consuming Risk for adhesive deficiencies is greater Failure rates seems to be slightly higher
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Extensive laboratory work required ď Ž Risk of debonding is high ď Ž
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Conclusion when the laboratory and the clinical procedures are strongly adhered,indirect bonding is undoubtedly a valuable technique. It proves itself by saving chair side time which is the most valuable for a practitioner. www.indiandentalacademy.com
If not for the labial technique,it is definitely a boon for the lingual operating system
Thank you ! www.indiandentalacademy.com