An assessment of extraction versus nonextraction orthodontic treatment using the peer assessment rating (PAR) index.

The extraction of teeth for orthodontic purposes has always been a controversial subject in the specialty. The purpose of this study was to assess the outcome of orthodontic treatment in 100 patients treated with the extraction of four premolars and compare it with the outcome of 100 patients treated without extractions, using the peer assessment rating (PAR) index. Records were selected from 1,198 consecutively completed cases treated by a single provider (MGH) between 1981 and 1995. We chose the first 100 finished patients in each group (extraction and nonextraction) who were under the age of 16 and had no deciduous teeth at the start of treatment. The results of this study show that average treatment time for the extraction group was 29.7+/-6.1 months compared with 26.0+/-7.2 months for the nonextraction group. The extraction group had significantly higher initial PAR scores (T1-PAR ext = 30.01+/-8.20 vs. T1 PAR nonext = 25.21+/-8.55), with greater initial maxillary anterior crowding (PAR ext value = 6.05+/-3.85 vs. PAR nonext value = 4.21+/-2.90) and greater initial overjet (PAR ext value = 1.82+/-1.01 vs. PAR nonext value 1.28+/-1.04). All pretreatment differences were significant at the p < or = 0.0001 level. Although significantly different at the beginning of treatment, both groups were statistically identical at the end (PAR T2 ext = 6.18 + 3.04% reduction = 79.4% compared with PAR T2 nonext = 5.64 + 3.08% reduction = 77.6%). In conclusion, the results demonstrate that, given an additional 3 months of treatment, it is possible for an orthodontist to produce dento-occlusal relationships in extraction patients that are as good as those achieved in nonextraction cases.

Functional and cosmetic reconstruction of the facial lower third associated with placement of the transmandibular implant system.

PURPOSE: Conventional preprosthetic procedures have typically focused on improvement of denture base stability and retention and have ignore patients' concerns about facial appearance and articulation difficulties. Soft tissue procedures have been developed, combined with insertion of the transmandibular implant (TMI) system through a submental incision, for functional and cosmetic reconstruction of the lower face to improve speech and facial esthetics, and prevent gingival hyperplasia along the lateral posts of the implant. PATIENTS: The surgical procedure was evaluated in 146 patients with slight, moderate, severe, and extreme mandibular atrophy classified according to the proportion of muscle origin loss on the edentulous mandible. Preoperative, 3-month, and 1-year postoperative full-face and profile photographs were taken. Patients also were questioned about their satisfaction with their facial appearance and speech at these intervals. Gingival hyperplasia along the TMI posts was scored as present or absent. RESULTS: Satisfaction with the soft tissue reconstruction in 146 patients treated according to this protocol was high, with almost every patient describing the positive comments they had received from their friends and relatives. Postoperatively, none of the patients requested a temporary denture to use during the 12-week incorporation period, although this was a common cosmetic and speech concern preoperatively. Gingival hyperplasia secondary to muscle pull was controlled satisfactorily. CONCLUSIONS: With the described technique for placement of the TMI system, not only is masticatory function improved, but also the lower third soft tissues of the face are functionally and cosmetically reconstructed to the satisfaction of the patients.

The transmandibular implant: from progressive bone loss to controlled bone growth.

PURPOSE: In a prospective study, 146 consecutive transmandibular implant (TMI) patients were treated according to revised surgical and prosthetic protocols to induce and control bone growth. Revisions included 1) placement of transosseous posts and cortical screws between the mental foramina so that two threads extended beyond the alveolar crest of the mandible without protruding through the mucosa and 2) fabrication of an implant-borne prosthesis that rested on the retromolar pads with a gap of 2 mm between the denture base and the mucosal tissues in the saddle areas. PATIENTS AND METHODS: Measurements of the height of the mandible were made using a digital millimeter calliper and panoramic radiographs, with the enlargement calculated for each radiograph. The follow-up period ranged from 18 to 51 months. RESULTS: Bone growth was present in 131 of the 146 patients whereas the bone resorption was arrested in the remaining patients. Increase in bony apposition varied from 9 mm in patients with severe mandibular atrophy to 2 mm in patients with mild atrophy. CONCLUSION: The revised surgical and prosthetic protocols for TMI insertion and rehabilitation are advocated to prevent further alveolar resorption and to promote bone growth in patients with mandibular atrophy.

Osseous changes following placement of the transmandibular implant system in edentulous mandibles.

The transmandibular implant system is designed for the reconstruction and rehabilitation of the endentulous mandible utilizing an extraoral approach. Transmandibular implants were placed in 19 patients and mandibular bony changes were followed using standardized panoramic radiography. Eleven sites were identified on each postoperative radiograph and the percentage of radiographic enlargement was calculated for each site. The true bony changes were then computed for both short-term (9.4 months) and long-term (53.4 months) follow-up. Patients with an average mandibular height in the saddle areas of 3.5 to 8.9 mm showed bilateral bony regeneration in the saddle areas and over the most distal cortical screws of the implants. Most of these bony changes were seen in the first year, but continued beyond that time. Patients with residual bone height of 9.0 to 12.9 mm had little bone change, while patients with bone height of 13.0 to 20.5 mm demonstrated slight resorption. Theories for the observed changes are presented. The transmandibular implant is especially indicated for the severely atrophic mandible because its position within the mandible and the rigid box frame design of the implant promote bilateral bone regeneration distal to the framework of the implant.

Prosthodontic considerations for the transmandibular implant.

The transmandibular implant has been designed to provide the patient with a severely atrophic mandible an implant that will bear the masticatory load. Thirteen edentulous patients treated with maxillary complete dentures and mandibular overdentures retained by the transmandibular implant were examined biannually for 2 years. Prosthodontic complications included the development of parafunctional habits, "combination syndrome," and epulis in association with the mandibular denture. Surgery was necessary to control chronic mucosal irritation related to muscle pull in one patient. Among the soft tissue parameters, plaque index, gingival index, and sulcus depth demonstrated statistically significant correlations (Spearman). All patients reported an absence of discomfort and those with previous functional complaints reported the ability to masticate all foods. Patient response to overdenture reconstruction with the transmandibular implant seems to be similar to that observed with the combination case. Oral hygiene appears to be directly related to the soft tissue response.

The transmandibular implant: a 2-year prospective study.

Thirteen consecutive patients with complaints of dysfunction and pain associated with a mandibular denture were treated with the transmandibular implant. The implant was placed from a submental approach with an atraumatic surgical technique. No load was placed on the implant for 12 weeks. Patients were evaluated for pain, paresthesia, healing of the submental wound, soft tissue response, radiographic change, and mobility of the implant for a period of 2 years. Patient satisfaction was recorded at the 1- and 2-year examinations. The results demonstrate the reliability and reparability of the transmandibular implant system.