INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
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ACKNOWLEDGEMENT Dr.E.Munirathnam Naidu Principal Meenakshi Ammal Dental College & Hospital
Dr.P.Jayakumar Vice Principal & Head Department Of Orthodontics All The Staff Members & Post Graduate Students www.indiandentalacademy.com
Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future scope
Conclusion www.indiandentalacademy.com
Introduction….
Face is a complex structure that has always challenged the orthodontist for a very long time. The face (Profile) is considered largely during treatment planning, which is determined predominantly by the rotation of mandible. It was “Bjork” (1969) with his studies opened new vistas on understanding the rotation of mandible, which he said that it is a complex phenomena and rightly published an article “Rotation A Puzzle” It was after this eye opener, treatment was focused on the “Face” than the “Base” . In this presentation an effort has be made, not only to understand the thewww.indiandentalacademy.com rotation of mandible but also its effects on treatment.
Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
Historical Perspective…. “BELCHIER & DUHAMMEL” (1736 to 1740 ) Investigated bones with the help of “Madder Root Die” & published an article “Root which stains bone Red” Phase of Transition
Die to Implant.
“DUHAMMEL”(1750) implanted wires to bones.
“JOHN HUNTER”(1754) began work on mandible
“JOHN HUNTER”(1764) proved mandibular remodeling is www.indiandentalacademy.com possible
Historical Perspective….
1st implant study by “G.Humphry”,boring hole in the pigs mandible & tying wire to it . This was published in an article “Growth of the Jaws” (1871)
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Historical Perspective…. “JOHN HUNTER”(1771) “Natural History of Human Teeth”describing “Ideal Occlusion”&“Mandibular Growth”
“LUCE” (1889 – 1900) worked on condyle & termed “HINGE AXIS” “BENNETT” (1908) Gave “ROTATIONAL THEORY”
“KEITH & CAMPION”(1922) studied growth of craniofacial www.indiandentalacademy.com
structures
Historical Perspective….
An illustration showing the lengthening of the Mandible occurring Dorsally form the published article “The Natural History Of The Human teeth”by “HUNTER” (1771) www.indiandentalacademy.com
Historical Perspective…. “BRASH”(1924) proved condylar hinge movement
(1930) Ceph studies were done - not very reliable
“BJORK”(1951) started implant studies on the jaws
“POSSELT et al” (1952) did studies on Mandibular Motion www.indiandentalacademy.com
Historical Perspective….
“BJORK”(1955) Phrased the term “Growth Rotation”
“BJORKS & Co Workers”(1960) Longitudinal studies with implants
(1969) Orthodontic Specialty focused attention on “Mandibular Rotations”
(1983) SKIELLER & Co Workers gave importance to jaws www.indiandentalacademy.com especially to Mandible during treatment planning
Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
Mandibular rotation …! Why? Normally changes that occur in the facial complex helps the clinician to identify & diagnose a problem correctly so as to provide the optimal treatment. It is therefore essential for us to be aware of, How the face changes ,Where & When it occurs & How it takes place ?. So sound understanding of growth of the Maxilla & Mandible is necessary to understand the rotation of the mandible,which predominantly determines www.indiandentalacademy.com the facial type of an individual.
Mandibular rotation ‌! Why? Maxillary Growth
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Mandibular rotation ‌! Why? Mandibular Growth
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Mandibular rotation ‌! Why? Total Growth Effect
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Possible Maxilo-Mandibular Skeletal Combinations
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Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
Types Of Rotation……! Classification It is mandatory that growth follows “Cephalocaudal
Growth” trend & hence it is inevitable for the mandible to compensate more than the maxilla to derive at an acceptable compromised profile.
The compensation of the mandible is more because it is the only mobile bone in the entire Cranio Facial Complex.
The basic movements of the mandible are Upwards & Forwards (Anti Clockwise) Downwards & Backwards (Clockwise) Lateral Excursions
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Classification….! Mandibular Rotation can be broadly classified into: During Growth During Treatment
During growth:1. “PROFFIT”
Internal Rotation Total Rotation External Rotation Total Rotation = Internal Rotation – External rotation www.indiandentalacademy.com
Classification….! 2. “SOLOW & HUSTON”
True Rotation Apparent Rotation Angular remodeling of lower border Apparent Rotation = Total Rotation – Angular Remodeling Of Lower Border 3. “SHUDDY”
Clockwise rotation Counterclockwise Rotation www.indiandentalacademy.com
Classification….! 4. “BJORK”
Forward Rotation Type - I - around the condyle. Type - II - around the incisors. Type - III - around the premolars.
I
II
III
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Classification….! Backward Rotation Type - I - around the condyle. Type - II - around the most distally occluding molar I
II
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Classification….! 5. “BJORK & SKIELLER”
Matrix Rotation – around the condyle (A) Intra Matrix Rotation – centered within the body (B) Total Rotation
Total rotation = Matrix rotation + intra matrix rotation
A B
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Classification….! During Treatment:Treatment mechanics inevitably changes the position of the mandible.
These Mechanics can be either “SKELETAL or DENTAL”
SKELETAL During Growth Period:-
Head Gear Therapy Myo functional Therapy…..ect ! www.indiandentalacademy.com
Classification….! After Growth Period:-
Lefort surgeries
Upward Impaction
I II High Lefort
Downward Impaction
DENTAL Distalization Mesialisation Molar extrusion Intrusion www.indiandentalacademy.com Molar
Schematic Explanation‌!
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Schematic Explanation‌!
= Low Angle = Normal Angle = High Angle
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Thus any treatment change alters the position of the mandible which in turn alters the profile ( long or short face).
Alterations in the position of the mandible due to treatment usually takes place around the condyl ..i.e., rotation takes place as a mandible as a whole.
This concept of rotation of the mandible during treatment is used for the study conducted in our department to calculate the rotation of the mandible. www.indiandentalacademy.com
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Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
Aims & Objective of the study…..! To assess the rotation of the mandible for
every 1 mm of movement of the molar.
To derive on a “Calculated approach” to
assess the rotation with the help of “Cephalometric & O.P.G “ analysis.
To apply this calculated approach,during the
planning phase of pre - surgical orthodontics , so as to predict the rotation of the mandible accurately.
To use the calculated value for the fabrication of surgical splint to aid the surgeon in easy & timely surgery. www.indiandentalacademy.com
Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
Materials & Methods….! 20 Cases undergoing Begg mechanotherapy were Selected.
Both Males & Females between the age group of 15yrs to 25yrs were considered.
All the patients had Bimaxillary Dental Proclinaiton & underwent all1st Bicuspids extraction.
Begg stage - I arch wires were placed with 35 to 40
degrees of anchor bend & 2 to 21/2 Oz of force used.
At the end of stage - I OPG & Lateral Cephalogram were taken.
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Materials & Methods….! Pre treatment & End of stage - I OPG & Cephalometric X- rays were assessed for the following land marks,
OPG land marks:- [WEBER.J.S.URSI.et all,JCO - 1990 - March (166 - 173) Right 6 to orbital plane Left 6 to orbital plane Right 6 to mandibular plane Left 6 to mandibular plane www.indiandentalacademy.com
OPG - Land Marks
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Materials & Methods….! Cephalometric land Marks (Angular) FMA GoGnSn ArGoGn Upper Go Lower Go Occl Plane to Sn Cephalometric Land Marks (Linear) N Ans Ans Gn Cd towww.indiandentalacademy.com Ptm
CEPH - Land Marks Linear Cd to Ptm NAns AnsGn Angular FMA GoGnSn ArGoGn UGo www.indiandentalacademy.com
LGo
Materials & Methods‌.!
The X - Rays of the 20 patients were analyzed for the land marks mentioned & tabulated as follows: Patient Name: I.D.No: Protocol Pre Rx End of Stage I Inference F.M.A GoGnSn ArGoGn U.Go L.Go Rt 6 to Orbital plane Lt 6 to Orbital Plane Rt 6 to Mand Plane Lt 6 to Mand Plane Cd to Ptm N Ans www.indiandentalacademy.com Ans Gn
Materials & Methods….! The readings obtained from the tabulated values were analyzed & related as follows,
Every 1 mm of Molar Extrusion [OPG] {Mo Ex}
Increase in Lower Anterior Facial Height {LAFH}.
Downward Backward Rotation Of Mandible {Ro Mad}.
Change in the condylar position {Cd Ptm}
The readings were statistically deduced & were given in a Ratio Format.i.e..
www.indiandentalacademy.com MoEx : LAFH : Ro Mad :Cd Ptm.
Materials & Methods….! The ratio thus deduced was used in a “Reverse Logical Sequence” to predict the auto rotation of the mandible.
Cases having “Vertical Maxillary Excess”were selected after necessary investigations were done (Ceph, Model analysis.etc).
10 patients both Males & Females were selected, between the age group of 20 to 28 yrs.
All selected cases were discussed with the oral surgeons & presurgical orthodontics were done . www.indiandentalacademy.com
Materials & Methods….! The cases selected were treated with 0.022’ Roth prescription for necessary decompensations. At the end of the pre surgical phase X-Rays (Ceph & OPG) were taken & the prediction of the autorotation was done to obtain a “Predicted Value”. After face bow transfer, the cast was mounted on the articulator (HANAU) & the “Predicted Value” was used to do the mock surgery for the preparation of the splint. The splint thus made i.e. “Predicted Splint”is used during surgery for easy & timely surgery. After 3 wks of the surgery a Lateral Ceph was taken to check the efficacy of thewww.indiandentalacademy.com prediction
Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
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Case Report Begg….! Boopathy 20 Yrs Male Teeth Placed in the Front Ectomorphic Body Type, Dolico cephalic Head, Leptoprosophic Face.
Symmetrical Face , Average Clinical
FMA , Convex Profile,Incompetent Lip , Acute Nasolabial Angle & Deep Mento labial Sulcus
Class- I Molar & Canine , Plroclined Upper & Lower Incisors,Over Jet of 10mm &Over Bite of 4.5mm.
All Four Ist Bicuspids Extraction was planed & www.indiandentalacademy.com strapped Up with Beggs.
PRE - Rx - INTRA ORAL & EXTRA ORAL
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PRE Rx - OPG & LATERAL CEPHALOGRAM
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END OF STAGE - I- INTRA ORAL
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END OF STAGE -I- OPG & LATERAL CEPHALOGRAM
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SUPERIMPOSITION‌!
Pre Stage- I
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Patient Name: Bhoopathy 20/M I.D.No: 60857 Protocol Pre Rx End of Stage I Inference F.M.A 23 26 >3 GoGnSn 30 33 >3 ArGoGn 125 127 >2 U.Go 52 52 0 L.Go 73 75 >2 Rt 6 to Orbital plane 28 31 >3 Lt 6 to Orbital Plane 29 31 >2 Rt 6 to Mand Plane 32 35 >3 Lt 6 to Mand Plane 33 36 >3 Cd to Ptm 28 25 <3 N Ans 49 49 0 Ans Gn 67www.indiandentalacademy.com 70 >3
The values thus obtained from the tabulation were analyzed statistically and the following ratio was obtained. 3mm of molar extrusion
3mm increased Lower anterior Facial height.
2Deg Increase in Mandibular rotation.
3mm Reduction From Condyle to Pterygo Maxillary Fissure Point
MoEx : LAFH : Ro Mad : Cd Ptm = 3 : 3 : 1 : 3 (2deg = 1mm) www.indiandentalacademy.com
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Case Report Orthognathic….! Sundari 23 Yrs Female Teeth Placed in the Front Ectomorphic Body Type, Mesocephalic Head, Leptoprosophic Face.
Symmetrical Face , High Clinical FMA , Convex Profile,Incompetent Lip , & Posterior Divergent
Class- II Molar & Canine , Plroclined Upper & Lower Incisors,6mm incisor exposure, Gummy Smile Over Jet of 6mm & Over Bite of 3mm.
Reverse Orthodontics (15,25,34 & 44)extn
& strappedwww.indiandentalacademy.com Up with PAE Roth .022’& Lefort I 5mm of Upward Impaction.
PRE Rx PHOTOS
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PRE TREATMENT OPG & CEPH
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PRE SURGICAL
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PRE SURGICAL CEPH & OPG
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PREDICTED CEPH
Maxilla & Molar moved up by 5mm. Red Predicted Face. Blue Pre surgical
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FACE BOW TRANSFER MOCK SURGERY & PREDICTED SPLINT
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DURING SURGERY
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IMMEDIATE POST - OP
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POST SURGICAL CEPH & OPG
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POST - OP SETELLING
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FACE PREDICTION (with ratio obtained) www.indiandentalacademy.com
PROFILE-COMPARISION
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Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
Future Scope…! This study should be conducted on large group to check for its “Reliability Constant”.
The muscle structures around the mandible plays a major role in its movement & hence it should be considered ( For which a study is in progress to assess the muscles function of the mandible with the help of Ultrsonography).
TMJ especially condyle is a complex structure &
so are is its movements ,hence a MRI & C.T study will be more essential to check its function.
Once these Diagnostic aids become reachable
for the common man it would be easy for every body to opt for prediction results, which in turn would increase the efficacy of the orthodontist www.indiandentalacademy.com
USG - -Studyâ&#x20AC;Ś!
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Left Lateral Pterygoid - Protrusion
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Right Lateral Pterygoid -Protrusion
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Left Lateral Pterygoid - Excursion
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Right Lateral Pterygoid-Excursion
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Left Temporalis - Clenching
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Right Temporalis - Clenching
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Left Masseter- Clenching
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Right Masseter- Clenching
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CT SCANâ&#x20AC;Ś.!
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TMJ - CTâ&#x20AC;Ś!
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3-D RECONSTRUCTION…!
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MRI - TMJâ&#x20AC;Ś!
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MRI-SCANâ&#x20AC;Ś!
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MRI-SCAN Land Marksâ&#x20AC;Ś!
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Close up view of TMJ Different Positions
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Close up view of TMJ Different Positions
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Close up view of TMJ Different Positions
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Lay - out……! Introduction Historical Perspective Mandibular Rotation…! Why? Types of Rotation….! Classification Study Done Aims & Objective Materials & Methods Case Reports Future Scope
Conclusion www.indiandentalacademy.com
Conclusion…! With this study the clinicians is able to accurately predict the “Mandibular Rotation”.
The results of this study can be used effectively during treatment planning of surgical cases where pre surgical orthodontics is necessary.
The “ Truth Of Future Orthodontics” is to use this easy calculated value, for “Nature Gave You The Face , But you Have To provide the Expression”
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Before I Concludeâ&#x20AC;Ś..!
A patriot is a man working for his country's future instead of boasting of its past.
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According To Meâ&#x20AC;Ś.!
An orthodontist is a man working for his fraternityâ&#x20AC;&#x2122;s future instead of boasting of its past. www.indiandentalacademy.com
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