Copy of jc presentation 29 oct o9 /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078

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  • 1. Early treatment of vertical skeletal dysplasia : The hyperdivergent phenotype INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • 2. Introduction • Early treatment is indicated. ( Nanda SK ; Am J Orthod Dentofacial Orthop 1988 ; 93 : 103-16) • Factors associated with favorable growth in patients with hyperdivergent phenotypes : a. Increase in posterior facial / anterior facial ratio. b. An average or greater amount of „true‟ forward mandibular rotation. c. More of anterior direction of condylar growth. d. Enhanced condylar growth. (In short , mandible is displaced more anteriorly than inferiorly) ( Vaden JL ; Am J Orthod Dentofacial Orthop 1994 ; 105 : 438-43 ) ( Bjork A ; Eur J Orthod 1983 ; 5 : 1-46 ) www.indiandentalacademy.com
  • 3. • Commonly used orthodontic appliances redirects condylar growth posteriorly , rotates mandible backwards and increases anterior facial height. ( Hultgren BW ; Am J Orthod ; 1978 ; 74 : 388-95 ) • Control of vertical dimension is probably the single most important factor in correction of the hyperdivergent case. ( Fotis V ; Am J Orthod 1984 ; 86 : 224-32 ) • Orthodontists attempt to limit vertical dimension increase in growing patients by one or more following methods: 1. High pull headgear with or without splint. 2. Extraction therapy. 3. Bite blocks ( active or passive ). 4. Vertical pull chin cup. 5. Any of the combination.www.indiandentalacademy.com
  • 4. • High pull head gear modifies maxillary growth but compensatory eruption of the mandibular molars prevents autorotation of the mandible and control of anterior facial height. ( Baumrind S ; Am J Orthod 1981 ; 80 : 17-30 ) • High pull head gear attached to a splint modifies maxillary growth effectively to a more postero-superior direction ; does not correct mandibular dysmorphology. ( Caldwell SF ; Am J Orthod 1984 ; 85 : 376-84 ) • Extraction therapy produces effective dento-alveolar compensation , molar eruption during space closure negates potential improvement of facial height. (Staggers JA ; Am J Orthod Dentofacial Orthop 1994 ; 105 : 19-24) www.indiandentalacademy.com
  • 5. • Combination of high pull head gear and extraction therapy appears to have similar effect with even more eruption of lower molars. ( Dougherty HL ; Am J Orthod 1968 ; 54 : 29-49 ) • Bite blocks have been shown to be effective for controlling anterior facial height in both animal models and clinical trails . ( Kuster R ; Eur J Orthod 1992 ; 14 : 489-99 ) • Magnetic bite blocks produce significant treatment changes but they can also create a. Asymmetric mandibular posture & subsequent unilateral crossbite due to shearing forces of repelling magnets. b. Increased root resorption due to excessive forces. ( Melson B ; Am J Orthod Dentofacial Orthop 1995 ; 108 : 500-9 ) www.indiandentalacademy.com
  • 6. • Vertical skeletal excess anteriorly is commonly accompanied with transverse maxillary constriction. • Active expansion of maxilla may lead to unfavorable inferior displacement of maxilla and mandible. (Wertz R ; Am J Orthod 1977 ; 71 : 267-81) • Bonded palatal expanders have been shown to minimise inferior displacement in posterior maxilla whereas bonded and banded palatal expander show similar inferior displacement for anterior maxilla. (Asanza S ; Angle Orthod 1997 ; 67 : 15-22 ) • To counteract inferior anterior maxillary displacement and increase in mandibular plane angle , chin-cup may be an effective appliance. (Majourau A ; Am J Orthod Dentofacial Orthop 1994 ; 106 : 322-8) www.indiandentalacademy.com
  • 7. • Hence , this study examines the effects of a novel treatment regime consisting of : a. Lip seal exercises. b. Bonded palatal expander constructed to function as a bite block. c. Banded lower Crozat / lip bumper. d. High pull chin cup. • Aim of the study : To whether this treatment regime a. Change the amount and direction of true mandibular rotation. b. Alter the amount and direction of mandibular growth. c. Control mandibular and maxillary molar eruption . d. Improve the vertical skeletal relationship. www.indiandentalacademy.com
  • 8. • Materials and method : a. 38 patients from private orthodontic practice of Dr. Albert H. Owen in Austin , Tex. b. 38% of the patients had open bite , although not a selection criteria. c. 24 (65%) females and 14 (35%) males • Inclusion criteria : a. Diagnosis of vertical skeletal dysplasia based on clinical photographs and cephalometric assessment of the mandibular plane angle greater than 350. b. Mixed dentition at the start of treatment. c. Treatment of no less than 6 months with the same early vertical treatment protocol. d. High quality cephalometric records.www.indiandentalacademy.com
  • 9. • Exclusion criteria : a. History of temperomandibular dysfunction. b. Maxillofacial trauma c. Nasopharyngeal obstruction d. Missing or poor quality cephalograms e. Poor patient co-operation with any of the treatment protocols. • Control group : drawn from longitudinal data collected by the Human Growth Research Centre , University of Montreal , Quebec. (non orthodontic sample with a variety of malocclusion). • Mean age pretreatment : 8.2 yrs ( +/- 1.2 yrs ) • Mean age post-treatment : 9.5 yrs ( +/- 1.2 yrs ) • Mean treatment duration : 1.3 yrs (+/- 0.3 yrs)www.indiandentalacademy.com
  • 10. • The control and experimental subjects were matched based on age , sex , and mandibular plane angle. www.indiandentalacademy.com
  • 11. • Treatment protocol : Same practitioner performed all treatment to the same treatment protocol. • Lip seal exercises : a. To train the orbicularis oris muscle to become more active in creating an anterior oral seal. b. Thereby , diminishing mentalis activity. c. Use of lip disc for 60 mins per day with placement of hand on chin to detect and eliminate mentalis activity. • Banded Crozat / lip bumper in mandibular arch to gain expansion. a. - Cemented in place with a 2 to 3 mm activation for 8 weeks. b. - Reactivation : 1mm every 8 weeks.www.indiandentalacademy.com
  • 12. • Maxillary arch treated with bonded palatal expander with slow expansion • Activation : ¼ turn / week , ( 1mm / month ) for approximately 6 months. www.indiandentalacademy.com
  • 13. • Whether a patient wore chin cup was judged clinically on the basis of appearance of bite marks on the BPE acrylic. If no marks were seen ; patient was made to wear a high pull chin cup. • Force delivered :16 to 20 ounces of force per side • Duration : at least 14 hours per day and asked to record the time worn on a time card. • The direction of pull : approximately 450 upward and backward in relation to the occlusal plane. www.indiandentalacademy.com
  • 14. Measurements : • All lateral cephalogram digitised and traced by same technician. • Pre treatment (T1) and post treatment (T2) cephalograms were corrected for radiographic magnification. • 16 landmarks were digitised ( fig 3 ) • Intra-examiner reliability showed no significant systematic error. • Random measurement error ranged 0.2 to 1.5 mm avg. 0.7mm ( using method error statistics ) www.indiandentalacademy.com
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  • 16. Evaluation of treatment changes : • 19 traditional measurements : 9 angular and 10 linear • Horizontal and vertical displacement of 11 landmarks using cranial base superimposition • Mandibular superimposition to measure a. True mandibular rotation b. Mandibular dental movements c. Condylar growth d. Horizontal and vertical drift of mandibular landmarks. www.indiandentalacademy.com
  • 17. • Lateral cephalogram were superimposed on stable cranial and cranial base reference structures. • The tracings were oriented according to the “best fit” stratergy. • A cranial reference axis (CRA) oriented along S-N minus 70 (SN7) and registered on sella was marked on T1 tracing and transferred to the superimposed T2 tracing. • Horizontal and vertical positional changes of landmarks evaluated parallel and perpendicular to CRA. • Finally, T1 and T2 mandibles were superimposed using following natural references structures. www.indiandentalacademy.com
  • 18. • The skewness and kurtosis statistics showed that all variables were normally distributed. • Patients were divided into subgroups : a. Open bite and overbite groups. 16 of 38 patients had an openbite. a. Patients with chincup therapy and without chincup therapy. 30 of 38 patients were treated with chincup. • Mann-Whitney ; a nonparametric test ; used to test differences between sub-samples ; as sub-sample size is small. • Paired t test to detect significant treatment changes. • Student t test to compare control and treatment group.www.indiandentalacademy.com
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  • 27. Discussion: Efficacy ratings* of various modes of treatment on the maxilla, mandible, and dentition HPHG + HPHG + Passive Active Treatment Effect site HPHG splint Extraction extraction PBB VCC PBB under study Condylar growth/amount – – 0 0 0 ? 0 + Condylar growth/direction 0 0 0 0 – ? 0 + Mandibular rotation 0 0 0 0 + + + + Maxillary position + ++ 0 0 + ? + + Posterior face height – – 0 0 + ? 0 + Anterior face height 0 0 0 0 + ? + 0 Skeletal AP relations + + 0 0 + ? + + U6 position ++ ++ – ++ + + + + L6 position –– 0 – –– + + + + Overbite 0 0 + ++ ++++ + + + Overjet + + + ++ + ? + + *+, Improvement; –, worsening; ?, insufficient data. HPGH, High-pull headgear. PBB, Posterior bite-block. VCC, Vertical chincup. www.indiandentalacademy.com
  • 28. Discussion: • Although early orthopedic approaches have been established in the anteroposterior and transverse dimensions, the treatment approach for vertical skeletal dysplasia remains controversial. • Early treatment regime led to • Increased condylar growth ; altered direction of condylar growth ; increased true mandibular rotation ; increased posterior facial height ; and decreased anterior facial height for openbite patients, which subsequently led to • Anterior chin displacement ; controlled maxillary and mandibular molar eruption ; increased overbite; and decreased overjet. www.indiandentalacademy.com
  • 29. • Based on the assumption that treatment should be evaluated based on success or failure of all treatment objectives, this novel treatment must be considered one of the better approaches currently available. • Autorotation of mandible: a. In overbite subsample, autorotation centered around the incisors and hence did not decrease the AFH. b. In openbite subsample, pronounced effect was seen on AFH resulting in no significant increase during treatment period. c. It has previously been suggested that the lack of anterior contact may allow autorotation if the freeway space can be increased through intrusion of posterior teeth. ( Kalva V ; Am J Orthod Dentofacial Orthop 1989; 95 : 467-78) www.indiandentalacademy.com
  • 30. • Studies have shown that banded maxillary expansion predictably displaces the maxilla inferiorly 1 to 2 mm. (Asanza S ; Angle Orthod 1997 ; 67 : 15-22 ) • The results of this study showed no vertical displacement of PNS or ANS. • Augmentation of PFH is of equally important as inhibition of AFH. • Early treatment had significant effect on condylar growth leading to posterior facial height development. • Amount of true mandibular rotation was 2.7times in treatment group as compared to control group. • In treatment group, chin landmarks were anteriorly displaced twice that of control group. www.indiandentalacademy.com
  • 31. • The observed changes in AP chin position may be attributed to: a. the BPE appliance that was designed to infringe on the freeway space and, when combined with the high-pull chincup, acted as a functional appliance/bite-block b. the lip seal exercises, and c. normal muscle forces/mandibular posture or the high- pull chincup. • Treatment comparison of patients with chincup did not differ with those who were not. • As chin cup therapy was given on the basis of absence teeth marks on the acrylic ; assuming that these patients had inadequate masticatory muscle force ; chin cup may provide suitable alternative for normal muscular forces . www.indiandentalacademy.com
  • 32. Therapeutic changes in the dentition: • 1mm of relative upper molar intrusion • Except posterior bite blocks, all other vertical treatments have shown to increase molar eruption. • Lower molar eruption (0.8mm) was controlled and did not differ significantly from the control values. • Overbite and overjet improved significantly. • The overbite increase may have been due to the separation of the dentition with acrylic and subsequent increases in soft tissue and facial muscular force. • The lip seal exercises may also have acted similarly to augment incisor uprighting and extrusion. www.indiandentalacademy.com
  • 33. Limitations of the study : • Long term effects of the treatment regime have not been established. • Kuster and Ingervall found a 50% relapse of the overbite, complete relapse of the gonial angle change, and a 33% relapse of the true forward rotation after 1 year of magnetic bite-block therapy. (Eur J Orthod 1992 ; 14 ; 489-499 ) • Further studies with our novel treatment approach are needed to corroborate the findings of this study and evaluate the long-term stability of these treatment effects. www.indiandentalacademy.com
  • 34. Conclusion: • This protocol can be used in patients with discrepancies in all 3 planes of space. • The result supports the axiom “The whole is greater than sum of its parts” • If greater changes are desired than it might be necessary to extend the treatment. • In large vertical skeletal discrepancies, surgery might be the only alternative. • This treatment protocol can be a non-surgical approach in borderline cases of vertical skeletal dysplasia. • Early treatment approach is a promising direction for such patients. www.indiandentalacademy.com
  • 35. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com