Long-term outcome of surgical Class III correction as a function of age at surgery.

INTRODUCTION: In this study, we assessed whether the likelihood of a positive overjet 5 to 10 years after Class III surgery was affected by age at the surgery or the type of surgery and evaluated the amount and pattern of postsurgical growth. METHODS: Cephalometric measurements including overjet were evaluated from immediately postsurgery and long-term recall cephalograms of 104 patients who had had surgical Class III correction and at least 5-year recalls. The patients were classified as younger (

Long-term soft tissue changes after orthodontic and surgical corrections of skeletal class III malocclusions.

OBJECTIVE: To evaluate long-term soft tissue changes after orthodontic and surgical corrections of skeletal Class III malocclusions. MATERIALS AND METHODS: Postoperative cephalometric radiographs at 1 year and at 5 years or more after treatment were digitized for 92 patients who had surgical correction of their Class III problem by LeFort I maxillary advancement (n = 48), mandibular setback (n = 12), or a combination of the two procedures (n = 32) and for 25 patients who received orthodontic treatment only. RESULTS: For all groups, the mean changes were quite small. For most measurements, fewer than 20% of patients experienced long-term changes from 2 mm to 4 mm, and fewer than 10% experienced long-term changes greater than 4 mm. CONCLUSIONS: A smaller percentage of surgically treated Class III patients showed long-term soft tissue changes than did surgically treated Class II patients, but compared with both Class II patients and untreated adults they experienced greater long-term forward projection of the soft tissue chin.

Accuracy of measurements of mandibular anatomy in cone beam computed tomography images.

OBJECTIVES: Cone beam computed tomography (CBCT) images of ideally positioned and systematically mispositioned dry skulls were measured using two-dimensional and three-dimensional software measurement techniques. Image measurements were compared with caliper measurements of the skulls. STUDY DESIGN: Cone beam computed tomography volumes of 28 skulls in ideal, shifted, and rotated positions were assessed by measuring distances between anatomic points and reference wires by using panoramic reconstructions (two-dimensional) and direct measurements from axial slices (three-dimensional). Differences between caliper measurements on skulls and software measurements in images were assessed with paired t tests and analysis of variance (ANOVA). RESULTS: Accuracy of measurement was not significantly affected by alterations in skull position or measurement of right or left sides. For easily visualized orthodontic wires, measurement accuracy was expressed by average errors less than 1.2% for two-dimensional measurement techniques and less than 0.6% for three-dimensional measurement techniques. Anatomic measurements were significantly more variable regardless of measurement technique. CONCLUSIONS: Both two-dimensional and three-dimensional techniques provide acceptably accurate measurement of mandibular anatomy. Cone beam computed tomography measurement was not significantly influenced by variation in skull orientation during image acquisition.

Three-dimensional cone-beam computed tomography for assessment of mandibular changes after orthognathic surgery.

INTRODUCTION: The purpose of this study was to assess alterations in the 3-dimensional (3D) position of the mandibular rami and condyles in patients receiving either maxillary advancement and mandibular setback or maxillary surgery only. METHODS: High-resolution cone-beam computed tomography scans were taken of 21 patients before and after orthognathic surgery. Ten patients with various malocclusions underwent maxillary surgery only, and 11 Class III patients received maxillary advancement and mandibular setback. Presurgery and postsurgery 3D models were registered on the surface of the cranial base. A new tool was used for graphical overlay and 3D display with color maps to visually assess the locations and to quantify positional changes in the posterior border of the mandibular rami and condyles between superimposed models. RESULTS: The average displacements in condylar position were small--0.77 mm (SD, 0.12 mm) and 0.70 mm (SD, 0.08 mm)--for 2-jaw and 1-jaw surgeries, respectively (not significant, P >.05). All 2-jaw surgery patients had backward rotational displacements of the mandibular rami (mean, 1.98 mm; SD, 1.03 mm), with a maximum surface distance change of > or =2 mm in 8 of 11 subjects. For the 1-jaw surgery, all subjects had small backward rotational displacements of the mandibular rami (mean, 0.78 mm; SD, 0.25 mm), with only 1 subject having a maximum surface distance change > or =2 mm. The difference in mean backward rotational displacement was statistically significant (P <.01). CONCLUSIONS: The visualization of 3D model superimposition clearly identified the location, magnitude, and direction of mandibular displacement. The 3D imaging allowed quantification of vertical, transverse, and anteroposterior ramus displacement that accompanied mandibular, but not maxillary only, surgery.

Long-term stability of surgical class III treatment: a study of 5-year postsurgical results.

Previous studies have documented the stability of Class III surgical procedures in the first postsurgical year and during a postsurgical period > 2 years. To evaluate long-term changes, postoperative cephalometric radiographs at 1 year and > or = 5 years were digitized for 79 patients who had received either a bilateral sagittal split osteotomy for mandibular setback, a Le Fort I maxillary advancement, or a combination of the 2 procedures. From 1 year to longest follow-up, the mean changes were quite small. Eighty-five percent of the maxillary advancement group and the mandibular setback group and 80% of the bimaxillary surgery group showed less than 4 mm of postsurgical change from 1 year to > or = 5 years. Long-term, the mandibular setback alone was more stable than when combined with maxillary surgery. This is opposite of what was observed during the first postsurgical year. Bimaxillary surgery in Class III patients improved the stability of the mandibular setback short-term and the maxillary advancement in the short and long term if the maxilla was also moved down during surgery. This study also suggests that bimaxillary surgery in Class III patients is more stable than bimaxillary surgery in Class II patients. On questionnaires that evaluated patient perception, 92% of patients reported satisfaction with healing since surgery. Eighty-nine percent thought their experience was positive and were happy with the surgical results. The predominant problems were altered feelings in the face or mouth (68%) and surprise at the length of their recovery (41%).

Analysis of craniofacial development in children with hypohidrotic ectodermal dysplasia.

Ectodermal dysplasias (ED) are a heterogeneous group of inheritable disorders characterized by abnormal development of embryologic ectoderm derivatives. The purposes of this study were to: 1) create baseline cephalometric norms for male children with ED; 2) assess craniofacial growth and development in hypohidrotic ED male children with severe hypodontia, compared with non-ED children with class I dental relationships; 3) compare the craniofacial morphology of titanium dental implant-treated ED males with non-implant-treated ED males; and 4) correlate the severity of hypodontia to craniofacial dysmorphology. Cephalometric radiographs of class I individuals and implant-treated and nontreated ED groups were used to evaluate craniofacial morphology. Traditional cephalometric landmarks and measurements were used to compare groups using the generalized estimate equation analysis. Age, gender, and the number of permanent maxillary teeth present had a significant (P =.01) explanatory relationship with the craniofacial measures when comparing untreated ED children to norms. Mean craniofacial differences between ED and non-ED children still existed when the explanatory effects of these variables were controlled, indicating dysmorphology in several craniofacial structures (e.g., cranial base, mandibular length). The number of missing maxillary permanent teeth was significantly related with craniofacial dysmorphology in the ED population. Craniofacial morphology did not differ significantly between implant-treated and nontreated ED children, suggesting that treatment with intraosseous dental implants, as applied in this population, did not rescue normal craniofacial growth and development.

Incisor retraction and profile changes in adult patients / Retração de incisivos e modificação do perfil facial em pacientes adultos

The aims of this study were to evaluate the changes in the facial profile related to maxillary incisor retraction and to check for correlations between changes in the lip and changes in the positions of the teeth and alveolar bone during orthodontic treatment. Initial and final lateral cephalometric radiographs of 25 nongrowing Brazilian patients were selected for this study. All patients initially presented with Class I or II malocclusions and had their maxillary incisors retracted at least 2 mm during orthodontic treatment. Changes in lip positions, length, and width, as well as changes in the positions of the alveolar bones and incisors, were calculated. Statistically significant differences from pretreatment to posttreatment were observed for all measurements except for upper lip length and point A. A high correlation was demonstrated between changes in the lower lip sulcus and point B and between changes in the lower lip sulcus and the mandibular incisor. Changes in the maxillary and mandibular incisors did not show a high correlation to the total lip changes, but high correlation coefficients were obtained when the changes in lip width were excluded from the total lip changes. In other words, changes in lip width tended to mask the changes in lip position caused by retraction of the maxillary incisors