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Biomedical subjects

William R Proffit

Publications and source records attributed to William R Proffit.

8 recordsLinked to original sources
PubMed2003

Long-term follow-up of Class II adults treated with orthodontic camouflage: a comparison with orthognathic surgery outcomes.

Thirty-one adults who had been treated with orthodontics alone for Class II malocclusions were recalled at least 5 years posttreatment to evaluate cephalometric and occlusal stability and also their satisfaction with treatment outcomes. The data were compared with similar data for long-term outcomes in patients with more severe Class II problems who had surgical correction with mandibular advancement, maxillary impaction, or a combination of those. In the camouflage patients, small mean changes in skeletal landmark positions occurred in the long term, but the changes were generally much smaller than in the surgery patients. The percentages of patients with a long-term increase in overbite were almost identical in the orthodontic and surgery groups, but the surgery patients were nearly twice as likely to have a long-term increase in overjet. The patients' perceptions of outcomes were highly positive in both the orthodontic and the surgical groups. The orthodontics-only (camouflage) patients reported fewer functional or temporomandibular joint problems than did the surgery patients and had similar reports of overall satisfaction with treatment, but patients who had their mandibles advanced were significantly more positive about their dentofacial images.

Adolescent↗
PubMed2003

Clinical outcomes of Fränkel appliance therapy assessed with a counterpart analysis.

To evaluate whether the Fränkel Regulator-II (FR-II) induced mandibular growth rotations relative to the nasomaxilla and the middle cranial fossae, cephalometric changes in 28 treated Brazilian children were compared with changes in 28 untreated Class II children and in 28 children with normal occlusion. According to Enlow's counterpart analysis, the 3 groups were not significantly different initially in ramus alignment or relative ramus vertical dimension. These jaw relationships were maintained in both untreated groups. In the treated group, all children had overjet reduction, with correction of the dental arch relationship in 26 of the 28, and there was a significant trend toward a more forward ramus alignment (P =.002) and increased ramus relative vertical dimension (P =.0002). These treatment-induced changes showed a negative correlation with ramus alignment; ie, greater improvement was more likely in children who had backward ramus alignment before treatment and whose Class II malocclusion had not already been intrinsically compensated. Changes in the treated children were similar to but greater than those in the normal children, and different from those in the untreated Class II group. The data suggest that studies of skeletal variations with counterpart analysis can show ramus remodeling compensations from treatment that are missed with conventional cephalometrics.

Analysis of Variance↗
PubMed2002

Response of erupting human second premolars to blood flow changes.

The effect of infiltration of a vasodilator and a vasoconstrictor [2% lidocaine (lignocaine) without or with 1:100,000 adrenaline (epinephrine)] above the root apex of human second premolars in the prefunctional stage of post-emergent eruption was evaluated for 11 teeth in eight children. On two consecutive days, 30 min of high-resolution data on changes in tooth position were collected for each participant during each of four sessions, two in the afternoon and two in the evening, using an optical instrument based on Moiré magnification with 0.05 microm resolution. The immediate reaction to the 1.8 ml injection was extrusion of the tooth, which lasted 2-4 min. After that, in the majority of teeth receiving a vasodilator, the reaction was an increased rate of eruption. In teeth receiving a vasoconstrictor, a decrease in eruption or intrusion was noted after the initial extrusion. The low-frequency Trentini cycles characteristic of erupting teeth were immediately obliterated in all teeth receiving injections. In the next few minutes, the cycles reappeared in teeth receiving the vasodilator, but did not reappear or reappeared only partially in teeth receiving the vasoconstrictor. It appears that vascular changes can influence the rate of prefunctional post-emergent eruption.

Adolescent↗
PubMed2002

The use of self-reinforced biodegradable bone plates and screws in orthognathic surgery.

PURPOSE: This report describes the authors' experience with self-reinforced biodegradable bone plates and screws to stabilize maxillary and mandibular osteotomies. Patient acceptance, demographics, types of osteotomy, means of stabilization, etiology of the deformity, complications, and patient disposition are reviewed. PATIENTS AND METHODS: Seventy patients underwent 194 osteotomies of the maxilla and/or mandible. Stabilization of each osteotomy was achieved using self-reinforced polylactite bone plates and/or screws of similar size and configuration to that of titanium systems. Placement of the devices was accomplished transorally and transfacially, consistent with the osteotomy approach. Maxillomandibular elastics were used to control the position of the jaws in each patient. RESULTS: There was good patient acceptance of the material (70/74). Stabilization was accomplished as planned in all patients. Three patients experienced problems that resulted in immediate loosening of the bone screws. The remaining 67 experienced no short-term problems (6 to 24 months), and healing progressed uneventfully. In each case, acceptable occlusion and favorable aesthetic changes were noted. CONCLUSIONS: The experience with self-reinforced polylactite bone plates and screws to stabilize maxillary and mandibular osteotomies has been favorable on short-term observation.

Absorbable Implants↗
PubMed2002

Fränkel appliance therapy and the temporomandibular disc: a prospective magnetic resonance imaging study.

This prospective clinical study assessed the effect of the Fränkel Functional Regulator-II (FR-II) treatment on the position and shape of the articular disc of the temporomandibular joint. The sample included magnetic resonance images of 112 temporomandibular joints taken initially (T1) and after 18 +/- 1 months (T2). The subjects were 56 white Brazilian children who were beginning their pubertal growth spurt. They had Class II Division 1 malocclusions and were selected from 800 children in neighborhood schools. They were randomly dichotomized into either the treated group (treated with the FR-II for 18 months) or the control group (not treated during the observation period). Our findings showed a low prevalence (3.57%) of disc displacement in the 112 temporomandibular joints. Mandibular propulsion with the FR-II had no unfavorable effect on the temporomandibular joints of the treated group; 100% of the patients kept an upper and interposed disc position (closed and open mouth, respectively) at T1 and T2. The control group had 7.1% partial anterior medial disc displacement, both at T1 and T2. Regarding disc morphology, the control group showed biconcave-shaped discs in 82.1% of the joints, statistically similar to the treated group (89.3%) at the beginning of the observation period. At T2, the articular disc morphology of the control group was unchanged, but that of the treated group was significantly more normal (P =.016), progressing from nonbiconcave at T1 (10.7%) to biconcave at T2 (100%). Our results showed that disc displacement is not a complication of functional appliance therapy; in fact, such treatment might help some children with incipient temporomandibular disorders.

Chi-Square Distribution↗
PubMed2002

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Conflict of Interest↗
PubMed2002

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%).

Adult↗