TREATMENT PLANNING WITH DIGITAL ORTHODONTIC MODELS Jean-Marc Retrouvey, Liliya Nicholcheva, Nathan Light

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1 TREATMENT PLANNING WITH DIGITAL ORTHODONTIC MODELS Jean-Marc Retrouvey, Liliya Nicholcheva, Nathan Light INTRODUCTION Digital orthodontic models are an accurate and reliable record of the patient s occlusion. In addition, new software allows sectioning and alignment of teeth on the model to simulate or predict the result of orthodontic treatment. Recent studies have shown that these digital predictions of treatment outcomes are comparable with actual post-orthodontic treatment outcomes OBJECTIVE AND HYPOTHESIS The purpose of this project is to assess the proficiency of digital orthodontic models in predicting the outcomes of several possible orthodontic treatment plans. MATERIALS AND METHODS Case 1 Severe Class II Div I malocclusion Slight maxillary prognathism Severely proclined maxillary incisors Slight mandibular retrognathism Slight proclined mandibular incisors

2 12mm overjet Proclined maxillary incisors Full cusp CL2 Molar Full cusp CL2 Canine Bolton discrepancy missing lower incisor Case 2 CL II canine malocclusion with edentulous areas. Pre-orthodontic implant placement Normally positioned maxilla and mandible Proclined maxillary incisors Partial edentulism ½ cusp CL3 molar ½ cusp CL2 canine Missing 35, 45, 46 Mesially tipped molars Occlusal cant Lingually tipped 47 and 48 Bucally tipped 15, 16, and 17

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4 RESULTS Case 1 Objectives of treatment Retract and upright maxillary anteriors Achieve good interdigitation of posterior teeth Achieve acceptable overbite and overjet Treatment options Treatment #1: Extraction of 14, 24 with retraction of anterior dentition (70% anchorage) Full cusp Class II molars Class I canines 3 mm overjet 40% overbite Lower dentition is aligned but incisors are not uprighted

5 Treatment #2: Extraction of 14, 24 with retraction of anterior dentition (100% anchorage) 3/4 cusp Class II molars 1/2 cusp Class II canines 1 mm overjet 30% overbite 100% anchorage impossible to achieve without use of implants Treatment #3: Alignment, uprighting of lower anteriors, surgery Full cusp Class III molars 1/4 cusp Class III canines 2 mm overjet 50% overbite Impossible to upright anterior teeth; roots are torqued out of bone

6 Treatment #4: Alignment and surgery 1/4 cusp Class III molars Class I canines 2 mm OJ, 30 % OB Impossible to upright anterior teeth; roots are torqued out of bone Occlusal interferences on 17, 27, 37, 47 Treatment #5: Extraction of 14, 24, retraction (70% anchorage), uprighting of lower anteriors, surgery 1/2 cusp Class II molars 1/2 cusp Class III canines 1 mm OJ, 50 % OB Poor interdigitation of teeth

7 Case 2 Objectives of treatment Place prosthetic implant before orthodontic treatment to use for anchorage Upright and intrude mandibular molars Upright maxillary molars Align maxillary and mandibular incisors Predicted space after orthodontic treatment = 10.4 mm = space for implant placement Space available before start of treatment = 11.3 mm Treatment options Treatment #1: (1) Implant 46, molar uprighting (M-D), bridge 34-X-36 1/2 cusp Class III R molar 1/2 cusp Class II canines 2 mm OJ, 50 % OB Occlusal cant Occlusal interferences on L

8 Treatment #2: Implant 46, molar uprighting (M-L, B-L), bridge 34-X-36, lower IPR 1/2 cusp Class III molars 1/2 cusp Class II canines 2 mm OJ, 50 % OB Occlusal cant R posterior crossbite Treatment #3: Implant 46, molar uprighting (M-L), bridge 34-X-36, correction of occlusal cant Class I molars 1/2 cusp Class II canines 2.5 mm OJ, 40 % OB Correction of occlusal cant requires additional implants B-L angulation of left molars is not Ideal

9 CONCLUSION Our study has shown that new software for sectioning and alignment of teeth allows the dentist/orthodontist to evaluate the outcomes of several possible treatments. In addition, the software facilitates communication with the patient and other dental professionals, and may be used as a teaching tool to educate students/dentists about possible shortcomings of treatment. Continued software development however is necessary to increase its ease of use and efficiency with respect to user interface REFERENCES Bell A, Ayoub AF, Siebert P J Ortho 30: Costalos PA, Sarraf K, Cangialousi TJ, Efstratiadis S J Orthod Dentofac Orthoped 128: Joffe L J Ortho 31: Pair JW, Luke L, White S, Atchinson K, Engelhart R, Brennan J Orthod Dentofac Orthoped 120: Quimby ML, Vig KL, Rashid RG, Firestone AR Angle Orthod 74: Rheude B, Sadowsky PL, Ferriera A, Jacobson A Angle Orthod 75: Santoro M, Galkin S, Teredesai M, Nicolay OF, Cangialosi TJ Am J Orthod Dentofac Orthop 124: Tomassetti JJ, Taloumis LJ, Denny JM, Fischer JR Angle Orthod 71: Zilberman O, Huggare JV, Parikakis KA :