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Biomedical subjects

D P Callan

Publications and source records attributed to D P Callan.

At least 19 recordsLinked to original sources
PubMed2000

Histologic analysis of implant sites after grafting with demineralized bone matrix putty and sheets.

Grafting to restore lost alveolar bone is frequently used to enable placement of endosseous implants and improve cosmesis. Conflicting reports concerning the osteoinductivity of demineralized bone matrix (DBM) and historical use of synthetic bone graft substitutes has limited the use of DBM in oral and maxillofacial applications. Implant placement after bone grafting provides the unique opportunity to biopsy and histologically evaluate new bone formation. Bone grafting of the mandible or maxilla was performed to fill extraction sockets and restore ridge structures in a consecutive series of eight patients. DBM prepared as malleable putty (Grafton DBM Putty) or flexible sheets (Grafton DBM Flex) was used. Biopsies were taken at reentry, and histologic analysis determined the amount and quality of regenerated bone. Extensive new bone formation and minimal residual bone graft matrix were observed at an average of 5 months postoperative. The pattern of new bone maturity and remodeling varied by patient and the time in situ. Putty and Flex regenerated excellent bone height and width for the placement of dental implants, were easy to handle intraoperatively, and readily conformed to bony defects.

Adult↗
PubMed2000

Maintaining cosmetics and marginal bone with a dental implant.

Inherent concerns for all implant systems exist. These concerns include complex restorative procedures, abutment rotational problems, marginal bone loss, and, in some cases, less than ideal cosmetic results. To overcome or reduce these problems, a new implant has been designed. The implant has been evaluated in this prospective study. Thirty-three new design implants were placed in 11 patients for an average time of 27.25 months. The new implant design proved to be easier to restore, posed no abutment rotational problems, resulted in no marginal bone loss problems (positive bone maintenance), and produced exceptional favorable cosmetic results.

Adult↗
PubMed2000

Retrospective multicenter study of an anodized, tapered, diminishing thread implant: success rate at exposure.

Performance of a new tapered, threaded implant at exposure was evaluated retrospectively using conservative assessment criteria. The criteria used were intended to ensure that an implant in the early stages of failing as well as those implants that have clearly failed would be identified as such. These results reflect an evaluation preliminary to comparing the performance of the implant at exposure and its performance (i.e., success rate) observed after longer periods (i.e., > or = 1 year) of loaded service. Data from 663 patients treated in the setting of the authors' private practice offices were evaluated to assess the performance of the implant under representative "clinical practice" usage conditions. The implant success/failure criteria were prospectively defined and applied to data obtained in a masked fashion from patients' records. Neither the dentist nor personnel involved in the analysis of the data were aware of which patients were qualified for and included into the study. Of 1100 implants available for evaluation, 15 implants failed at or before exposure. The success rate at exposure was 98.6%. There was no correlation between the anatomical region in which an implant was placed and the incidence of implant failure. Implants placed in fresh extraction sites and/or grafted sites appeared to be more likely to fail at exposure. Conversely, the failure rate of implants placed using a single-stage surgical procedure was comparable to that of implants placed using a conventional two-stage surgical methodology. Immediately loaded implants experienced a success rate comparable to that of implants placed using conventional two-stage surgical procedures. Factors under the clinician's control may play a substantial role in determining implant performance at exposure.

Adolescent↗
PubMed2000

Multi-center clinical comparison of combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) and ABM in human periodontal osseous defects. 6-month results.

BACKGROUND: Intraosseous periodontal defects present a particular treatment problem. New bone replacement grafts offer promise for improved results. METHODS: The role of a synthetic cell-binding peptide (P-15), combined with anorganic [corrected] bovine-derived hydroxyapatite bone matrix (ABM), was compared to ABM alone in human periodontal osseous defects in a controlled, monitored, multi-center trial. Following appropriate initial preparation procedures, flap surgery with defect and root debridement was performed. Two osseous defects per patient were treated randomly with each procedure after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 to 7 months, re-entry flap surgery was performed for documentation and finalization of treatment. RESULTS: T test and Mann-Whitney U analyses of patient mean values from 33 patients revealed that the combination ABM/P-15 grafts demonstrated significantly better mean defect fill of 2.9 +/- 1.2 mm (72.9%) versus a mean defect fill of 2.2 +/- 1.4 mm (50.67%) for defects treated with ABM (P<0.05). Other hard tissue findings showed similar clinically superior results with the use of ABM/P-15. Relative defect fill results showed 81% positive (50% to 100% defect fill) responses with ABM/P-15 and 67% positive responses with ABM. There were 3.5 times as many optimal results (> or = 90% defect fill) with ABM/P-15 and twice as many failures (minimal response) with ABM. Soft tissue findings showed no significant differences between treatments. CONCLUSIONS: These results suggest that the use of the P-15 synthetic cell-binding peptide combined with ABM yields better clinical results than the ABM alone in intrabony periodontal defects.

Adult↗
PubMed1998

Loss of crestal bone around dental implants: a retrospective study.

The loss of crestal bone associated with dental implants is a significant clinical phenomenon. The occurrence of such bone loss will often compromise long-term prognosis and, if extensive, ultimately lead to failure. Relatively few studies have focused on the reasons for loss of crestal-supporting bone around implants, although numerous explanations for the phenomenon have been proposed. This retrospective investigation examines one potential causative factor for implant-associated crestal bone loss, which has only recently received attention, i.e., location of the implant/transmucosal abutment interface (ITAI) relative to the crestal bone. A retrospective clinical evaluation of 350 individual implants in 255 patients indicates a direct relationship between subgingival placement of the ITAI and loss of crestal supporting bone. In addition, scanning electron microscopic examination of 45 failed implants showed significant plaque accumulation at the ITAI, the transmucosal abutment/prosthesis interface (TAPI), and the interface between the implant smooth collar and subjacent plasma-spray coated surface.

Adolescent↗
PubMed1998

Multi-center clinical evaluation of combination anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) as a bone replacement graft material in human periodontal osseous defects. 6-month results.

A synthetic cell-binding peptide (P-15) combined with anorganic bovine-derived hydroxyapatite bone matrix (ABM) was compared to demineralized freeze-dried bone allograft (DFDBA) and open flap debridement (DEBR) in human periodontal osseous defects in a controlled, monitored, multi-center trial. Following appropriate initial preparation procedures, flap surgery with defect and root debridement was performed. Three osseous defects per patient were treated randomly with one of three procedures after surgical preparation. Appropriate periodontal maintenance schedules were followed, and at 6 to 7 months re-entry flap surgery was performed for documentation and finalization of treatment. Analysis of variation (ANOVA) and t test analyses of patient mean values from 31 patients revealed that the combination ABM/P-15 grafts demonstrated significantly better mean defect fill of 2.8 +/- 1.2 mm (72.3%) versus a mean defect fill of 2.0 +/- 1.4 mm (51.4%) for defects treated with DFDBA (P <0.05) and a mean defect fill of 1.5 +/- 1.3 mm (40.3%) (P <0.05) for defects treated with DEBR. Other hard tissue findings showed similar clinically superior results with the use of ABM/P-15. Relative defect fill results showed 87% positive (50% to 100% defect fill) responses with ABM/P-15, 58% positive responses with DFDBA, and 41% positive responses with DEBR. There were 8 to 9 times more failures (minimal response) with DFDBA and DEBR (26% to 29% frequency) than with ABM/P-15. Soft tissue findings showed no significant differences among treatments except for greater clinical attachment level gain with ABM/P-15 compared to DEBR. These results suggest that the use of the P-15 synthetic cell-binding peptide combined with ABM yields better clinical results than either DFDBA or DEBR. Further studies are needed to determine the relative roles of the ABM and/or the P-15 in these improved results.

Adult↗
PubMed1995

Creating the environment for implant success: an interdisciplinary approach.

With the continued advance of technology and the heightened awareness of patient expectations, the multidisciplinary approach to treatment planning for implant-supported restorations is now the foundation for the surgical and restorative procedures. This article reviews a systematic approach to treatment planning, involving the expertise of the restorative triad-the surgeon, the restorative dentist, and the laboratory technician-since each professional provides valuable contributions to the treatment planning, surgical placement, provisionalization, and the fabrication of the final restoration.

Alveolar Bone Loss↗
PubMed1993

Use of bovine-derived hydroxyapatite in the treatment of edentulous ridge defects: a human clinical and histologic case report.

The advent of AIDS has created patients fears regarding human tissue transfers, including bone grafts in dental surgery. In the face of these fears, alternative allograft materials are of increasing interest to clinicians. One such alternative is naturally derived xenogeneic hydroxyapatite (HA). In this study, two patients with edentulous ridge defects received bovine-derived HA grafts in conjunction with a dental implant treatment plan. The results were evaluated histologically. Both patients showed excellent clinical results with histological confirmation of osseous formation. The outcomes suggest that further consideration of the use of bovine-derived HA is merited as a means of remediating edentulous ridge defects.

Aged↗
PubMed1993

Restoration of the resorbed maxilla: a multidisciplinary approach.

The need for a multidisciplinary approach in implant restorations is well recognized today. This presentation describes the aesthetic restoration of the inadequate maxilla, involving augmentation of the grafting site, implant placement in the posterior regions to support the anterior restorations, and crown-and-bridge preparation. The learning objective of this article is a better understanding and execution of the multidisciplinary approach.

Alveolar Bone Loss↗
PubMed1993

Hard tissue regeneration for implant success.

The inevitable loss of alveolar bone following tooth loss deserves a prophylactic approach from the dental profession. By preserving bone through regenerative procedures, the patient option and likelihood of successful future dental implant treatment are enhanced. The use of fascia lata similarly extends surgical and restorative options to patients who otherwise might not be candidates for dental implants. A variety of materials is available for these procedures, but whichever are selected, it is imperative that the dental implant professional operate as a member of a team of interrelated disciplines if the results of dental implant treatment are to be optimized.

Alveolar Bone Loss↗
PubMed1993

Guided tissue regeneration without a stage 2 surgical procedure.

In the two cases described, the problems of insufficient bone and insufficient soft tissue in the edentulous ridge were addressed concurrently. Freeze-dried demineralized bone was used to fill the osseous defect. Freeze-dried fascia lata was used to prevent epithelial migration into the defect, act as a barrier, and eliminate a second surgery for membrane removal. This regeneration procedure can provide increased alveolar bone for better implant placement and esthetics.

Aged↗