Differential treatment planning for mandibular prognathism.
The treatment records of thirty-eight cases of mandibular prognathism treated by orthodontics means only (ORTHO) were evaluated. The pretreatment records of twenty cases of mandibular subapical esteotomy (SUB) and twenty cases of mandibular setback (SET) were evaluated for comparison and contrast with the pretreatment ORTHO records and with each other. Dental, skeletal, and soft-tissue parameters in the vertical and horizontal planes of space were recorded. Statistical analysis of means of parameters of the pretreatment records provided documentation of the discriminant variables in each of the following paired groups: ORTHO-SUB, ORTHO-SET, and SUB-SET. Analysis of the data as indicated above led to the following conclusions: 1. Three discriminant groups of mandibular prognathism of various degrees of severity were discernible when comparisons of treatment categories simulating clinical decisions were made. The ORTHO group was distinguished from the SUB group in the horizontal plane and, more strongly, in the vertical plane. The ORTHO group was distinguished from the SET group in the vertical plane and, more strongly, in the horizontal plane. The SUB group was distinguished from the SET group in the horizontal plane. 2. The physiologic developmental status of the patient should be carefully evaluated. 3. Anteroposterior dysplasias should be assessed relative to the cant of the mandibular plane. True denture base discrepancies can be noted relative to the occlusal plane. 4. Documentation of vertical dysplasias should include measurements of craniofacial divergence (SN-MP, FH-MP, and OP-MP). 5. In assessing the profile evaluation of the patient with mandibular prognathism, particular attention should be focused on facial contour angle (FCA), nasolabial angle (NLA), and relative lower lip protrusion (LLP). 6. Any numerical values obtained in the evaluation of the dental, skeletal, or soft-tissue characteristics of mandibular prognathism should be considered only as descriptive, diagnostic guides and not as components of a diagnostic formula.
D000539:Alveolar Process / Q000601:surgery; D002508:Cephalometry; D006801:Humans; D008334:Mandible / Q000002:abnormalities* / Q000601:surgery; D008445:Maxillofacial Development; D009967:Orthodontic Appliances; D010027:Osteotomy; D010347:Patient Care Planning; D011378:Prognathism / Q000601:surgery / Q000628:therapy*