Sethi, Ashok

The aim of the current ongoing study is to evaluate the long-term results of endosseous implants placed into autogenous bone grafts from intraoral donor sites. Patient selection for the correction of bone deficiencies was based on biomechanical and esthetic needs. Donor site selection was dependent upon the type of deficiency and the graft shape needed. Two-stage implants were placed after a healing period of 3 to 6 months, based on an assessment of the graft viability with radiographic and clinical parameters. Thus far, 118 implants have been placed in 60 patients whose alveolar ridges were deficient in height, width, or both height and width and were augmented. The patients were observed for up to 77 months. Two implant failures were encountered before implant exposure (1.7%). No further implants have been lost in function.

A total of 2,261 2-stage implants was placed in 467 patients in combination with angled abutments ranging from 0 to 45 degrees. These were observed over a period of up to 96 months, with a mean observation time of 28.8 months. Single and multiple teeth were replaced and restored using angled abutments. For patients who contributed multiple survival data, the data were considered dependent. Therefore, a mean survival estimation was performed. With a certainty of 95%, an estimated mean survival rate better than 98.6% after a 5-year observation period was calculated. The statistical comparison of 2 independent, randomized implant groups (with abutments angled between 0 and 15 degrees and between 20 and 45 degrees) by means of a log-rank test showed a probability of 0.84 (P value) that the survival functions are the same for both groups. Good esthetic and functional outcomes were observed. Keywords: dental abutments, osseointegrated dental implants, survival analysis

With the technique of maxillary ridge expansion, 449 implants were placed in 150 patients and observed over a period of up to 93 months. Thin maxillary ridges of adequate height and comprising 2 separate cortical plates with intervening cancellous bone were selected for maxillary ridge expansion and simultaneous implant placement. Two-stage implants were used and allowed to heal in a closed environment for 6 months prior to loading. Single and multiple teeth were replaced using this technique, and an estimated mean survival rate better than 97% after a 5-year observation period was calculated (95% confidence interval of the mean survival estimation: 98% ± 1%). Good esthetic and functional outcomes were observed. Keywords: alveolar ridge augmentation, dental implants, endosseous dental implantation, osteotomes, ridge expansion

Although the permucosal site of implants can be made to coincide with tooth position, the problem of aligning multiple abutments remains. To use the maximum amount of available bone, an implant must often be placed at an angle to the long axis of the prosthetic replacement tooth, and it also can deviate mesiodistally. This paper discusses a technique using trial abutments to create parallelism while ensuring that each abutment is ideally positioned with respect to the final restoration. The procedure also encourages patient acceptance by transferring the appearance created by a preliminary diagnostic waxup through to the finished prosthesis. Keywords: diagnostic waxup, hex guide pins, implant-abutment parallelism, osseointegrated implants, surgical template

Information gained by preoperative imaging techniques must be accurately related to the surgical site. The inability to do this severely diminishes the benefit of the diagnostic imaging. The CT scan is capable of providing considerable information regarding the jaws. The use of radiopaque markers to identify preselected points on the image is readily done by placing markers in the wax registration rims that are worn during the scan. The position of these markers is transferred to the mouth with a surgical template, facilitating surgery and reducing the incidence of anatomic accidents caused by lack of orientation. Keywords: CT scan, esthetics, osseointegrated implants, surgical templates