ABSTRACT
OBJECTIVE: To evaluate the role of genetics and tooth wear in the etiology of dental crowding through the analysis of a split indigenous Amazon population. MATERIALS AND METHODS: Dental crowding prevalence (n â=â 117), tooth wear (n â=â 117), and inbreeding coefficient (n â=â 288) were compared for both villages. A biometric investigation was performed by dental cast analysis of 55 individuals with no tooth loss. Mann-Whitney statistics, independent t-tests, and Fisher exact tests were used at P < .05. RESULTS: A high coefficient of inbreeding was confirmed in the resultant village (F â=â 0.25, P < .001). Tooth wear was not significantly different (P â=â .99), while a significantly higher prevalence of dental crowding was confirmed in the original village (PR â=â 6.67, P â=â 0.02). Forty dental arches (n â=â 20) were examined in the new group, and only one (2.5%) had a dental crowding ≥ 5 mm. In the original villages, we found 20 arches (28.6%) with dental crowding. No difference was observed for tooth size, while larger dental arch dimensions explained a lower level of dental crowding in the resultant village. CONCLUSIONS: Our findings downplay the widespread influence of tooth wear, a direct evidence of what an individual ate in the past, on dental crowding and emphasize the role of heredity, exacerbated through inbreeding, in the etiology of this malocclusion.
Subject(s)
Consanguinity , Diet/ethnology , Malocclusion/etiology , Population Groups , Adolescent , Adult , Brazil/epidemiology , Dental Arch , Female , Humans , Male , Malocclusion/ethnology , Malocclusion/genetics , Prevalence , Statistics, Nonparametric , Tooth WearABSTRACT
PURPOSE: To evaluate the association of 3-dimensional changes in the position of the condyles, rami, and chin at splint removal and 1 year after mandibular advancement surgery. PATIENTS AND METHODS: This prospective observational study used preoperative and postoperative scans of 27 subjects presenting with a skeletal Class II jaw relationship with a normal or deep overbite. An automatic technique of cranial base superimposition was used to assess the positional and/or remodeling changes in the anatomic regions of interest. The displacements were visually displayed and quantified using 3-dimensional color maps. The positive and negative values of surface distances in the color maps indicated the direction of the displacements. Pearson correlation coefficients and a linear model for correlated data were used to evaluate the association between the regional displacements. RESULTS: The postoperative adaptations in the chin position between splint removal and 1 year after surgery were significantly negatively correlated with changes in the borders of the posterior ramus (left, r = -0.73, P ≤ .0001; and right, r = -0.68, P = .00) and the condyles (left, r = -0.53, P = .01; and right, r = -0.46, P = .02), indicating that these structures tended to be displaced in the same direction. Even though the mean condylar displacement with surgery was less than 1 mm, individual displacements greater than 2 mm with surgery were observed for 24% of the condyles. The condylar displacements were maintained at 1 year after surgery for 17% of the condyles. CONCLUSIONS: The surface distance displacements indicated that the postoperative adaptations at different anatomic regions were significantly related.
Subject(s)
Cephalometry/methods , Imaging, Three-Dimensional/methods , Mandible/anatomy & histology , Mandibular Advancement/methods , Adaptation, Physiological/physiology , Adult , Chin/anatomy & histology , Chin/surgery , Cone-Beam Computed Tomography/methods , Dental Occlusion, Centric , Female , Follow-Up Studies , Humans , Image Processing, Computer-Assisted/methods , Male , Malocclusion, Angle Class II/surgery , Mandibular Advancement/instrumentation , Mandibular Condyle/anatomy & histology , Osteotomy/methods , Prospective Studies , Skull Base/anatomy & histology , SplintsABSTRACT
This patient report describes the treatment of a 10-year-old female with complete transposition of her impacted mandibular canines and lateral incisors. The patient had a Class I occlusion, and her mandibular lateral incisors were in crossbite with the maxillary central incisors. The treatment objectives were to create space for the impacted canines and align them with the incisors, one of which was extracted. After treatment, the appearance of the patient's teeth was improved, the occlusion was preserved, and overjet and overbite were corrected.
Subject(s)
Orthodontics, Corrective/methods , Tooth Eruption, Ectopic/therapy , Tooth, Impacted/therapy , Child , Cost-Benefit Analysis , Cuspid/pathology , Female , Humans , Mandible , Orthodontics, Corrective/economics , Tooth Eruption, Ectopic/complications , Tooth, Impacted/complications , Treatment OutcomeABSTRACT
The aim of this study was to evaluate changes in the facial profile resulting from the use of a twin block (TB) functional appliance. The sample comprised 38 patients (24 males and 14 females) with a Class II division 1 malocclusion. Nineteen subjects were treated with a functional appliance while the remaining 19, who did not undergo any intervention, served as the control. The mean age of the treated group was 9.5 years (SD 10 months) and of the control group 9.9 years (SD 13 months). Lateral cephalograms were obtained for all subjects at the initial consultation and again after one year. The changes in facial profile, resulting from treatment with the TB, were analysed after the influence of growth had been taken into account. The results showed a significant improvement in the facial profile, which closely followed the underlying dentoskeletal changes. Thus, the most significant effects were a total facial profile improvement, retraction of the upper lip and anterior movement of soft tissue pogonion (P < 0.05). Subjects treated with a TB appliance achieved improved facial harmony, but such changes were not observed in the control group.
