BIOPROGRESSIVE THERAPY-2
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
Use of superimposition areas to establish treatment design.
www.indiandentalacademy.com
Introduction • Changes due to normal growth and changes due to various treatment mechanics are different for each individual because of individual morphology and facial type.
www.indiandentalacademy.com
www.indiandentalacademy.com
www.indiandentalacademy.com
Describing the face There are three basic facial patterns: • Mesofacial • Brachyfacial • Dolichofacial From the eleven factor summary analysis, five angels are used to describe the face: • Facial axis angle • Facial angle • Mandibular plane angle • Lower facial height • Mandibular arc www.indiandentalacademy.com
1) Facial axis angle (90° ± 3 °)
www.indiandentalacademy.com
2) Facial angle (87 ° ± 3 °)
www.indiandentalacademy.com
Mandibular plane angle (26 ° ± 4 °)
www.indiandentalacademy.com
Lower facial height (47 ± ° 4 °)
www.indiandentalacademy.com
Mandibular arc (26 ° ± 4 °)
www.indiandentalacademy.com
Together these five angles determine weather the facial pattern is meso, brachy ,or dolicho facial. Approximately 70 % of malocclusions that we treat fall in meso facial range. It is important to establish what the facial type is because the reaction of treatment mechanics and the stability of denture is dependent upon the analysis of facial pattern. www.indiandentalacademy.com
Five superimposition areas Following the description of the face and determination of facial type we use five superimposition areas, superimposing the TIME ONE tracing against the VTO or any progress tracings, to evaluate the change that we expect will occur or has occurred due to growth or due to treatment mechanics. www.indiandentalacademy.com
The five superimposition areas are used to evaluate the face in following order: • • • • •
Chin Maxila The teeth in mandible The teeth in maxilla The facial profile
www.indiandentalacademy.com
Superimposition Area 1(Evaluation Area1) In normal growth the chin grows down the facial axis and the six year molars also grow down the facial axis.The facial axis rotates open or closed from the effects of mechanics, and other considerations as follows: • Facial axis opens one degree for 5 mm of convexity reduction. • Facial axis opens one degree for 3mm of molar correction. • Facial axis opens one degree for 4mm of overbite correction. • Facial axis may close with extraction. www.indiandentalacademy.com
www.indiandentalacademy.com
Superimposition Area 2(Evaluation Area 2) The second superimposition area ( Basion – Nasion at Nasion ) establishes evaluation area 2 to show any change in the maxilla( point A ). The basion-nasion-point A angle does not change in normal growth.
www.indiandentalacademy.com
The following are considered the maximum range of point A change with various mechanics : Mechanics • HG • Class II elastics • Activator • Torque • Class III elastics • Facial masks
Maximum range • -8mm • -3mm • -2mm • -1-2 mm • +2-3 mm • +2-4mm
www.indiandentalacademy.com
www.indiandentalacademy.com
Superimposition Area 3 (Evaluation Area 3 and 4) The Third superimposition area (corpus axis at PM) establishes evaluation are3&4 which together evaluate any changes that take place in mandibular denture. In evaluation area 3, we evaluate whether we are going to intrude, extrude…. In evaluation area 4, we evaluate the lower molars to determine what type of anchorage we need…… www.indiandentalacademy.com
www.indiandentalacademy.com
Superimposition Area 4(Evaluation Area 5& 6) • The 4th Superimposition Area the fourth superimposition area [palate at ANS] establishes evaluation area 5 and evaluation area 6,which together evaluate changes that takes place in maxillary denture. In normal growth, upper molars and incisors grow on their polar axis. www.indiandentalacademy.com
www.indiandentalacademy.com
Superimposition area 5(Evaluation Area 7) •
The fifth superimposition area (esthetic plane at crossing of occlusal plane) establishes evaluation area 7 with which we evaluate soft tissue profile. In normal growth ,face becomes less protrusive with reference to esthetic plane.We use superimposition area 5 evaluation area 7 to evaluate effect of our mechanics on soft tissue of the face. www.indiandentalacademy.com
Superimposition and evaluation demonstration. Using tracing of M.G.from part 3 VTO, five superimposition areas and seven evaluation areas to evaluate that VTO. IST SUPERIMPOSITION AREA(BA-NA AT CC POINT) FIRST CHECK POINT Place your VTO over the original tracing of M.G on Basion Nasion at CC point. You will see that facial axis has opened 1or 2 degrees. Therefore the mechanics will open the facial axis 1 to 2 degrees www.indiandentalacademy.com
Superimposition and evaluation demonstration
www.indiandentalacademy.com
Superimposition and evaluation demonstration • 2ND SUPERIMPOSITION AREA(BA-NA AT NA POINT) SECOND CHECK POINT • Place your VTO over original tracing of M.G on Basion Nasion at Nasion. Basion-Nasion-Point A angle does not change in normal growth. As you look at the tracing you would see that point A has been reduced by 2mm
www.indiandentalacademy.com
Superimposition and evaluation demonstration
www.indiandentalacademy.com
Superimposition and evaluation demonstration • 3RD SUPERIMPOSITION AREA(CORPUS AXIS AT PM POINT) THIRD CHECK POINT • Place your VTO over original tracing of M.G on Corpus Axis at PM. It shows that we would like to tip the lower incisor forward approximately 2mm and bring the lower molar forward approximately 4mm
www.indiandentalacademy.com
Superimposition and evaluation demonstration
www.indiandentalacademy.com
Superimposition and evaluation demonstration • 4TH SUPERIMPOSITION AREA(PALATE AT ANS) FOURTH CHECK POINT. • Place your VTO over original tracing of M.G on palate at ANS. Since we are bringing the lower incisors and lower molar forward , even though this case is class II malocclusion all we must do is to hold the upper molar to accomplish the class II correction. The upper incisor evaluation shows that we are going to retract and torque the upper incisors .it also shows the potential use of clssII elastics and torque on upper incisors is going to reduce Point A www.indiandentalacademy.com
Superimposition and evaluation demonstration
www.indiandentalacademy.com
Superimposition and evaluation demonstration • 5TH SUPERIMPOSITION AREA(ESTHETIC PLANE AT THE CROSSING OF OCCLUSAL PLANE ) • Place your VTO over original tracing of M.G on ESTHETIC PLANE where the occlusal plane crosses it ,we see that reduction of upper denture results in a great reduction in the soft tissue profile
www.indiandentalacademy.com
Superimposition and evaluation demonstration
www.indiandentalacademy.com
Conclusion • Super imposition can help us to achieve following objectives • 1) Basic description of cranial structures. • 2) Analysis of normal growth change. • 3) Treatment design • 4) An evaluation of growth and treatment results. www.indiandentalacademy.com
www.indiandentalacademy.com Leader in continuing dental education
www.indiandentalacademy.com