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Biomedical subjects

L Kaban

Publications and source records attributed to L Kaban.

9 recordsLinked to original sources

Factors influencing the long-term outcome of mandibular reconstruction.

PURPOSE: The aim of this study was to understand the association of 30 candidate variables with the outcome of mandibular reconstruction. PATIENTS AND METHODS: Seventy cases of mandibular reconstruction performed between 1976 and 1991 were identified. Medical records were reviewed for all patients. Thirty variables, including patient factors, preoperative preparation, and intraoperative and postoperative findings were determined for each patient. Bone graft outcome was evaluated in 2 ways: 1) Fisher's exact tests and logistic regression models were used to determine the association between the clinical parameters and the success of the bone graft at 1 year and 2) proportional hazard regression models were then used to identify the predictors of bone graft survival time from the 30 chosen variables. RESULTS: Multivariate analysis determined that greater blood loss during the procedure (P = .018) and the presence of postoperative recipient site complications (P = .010) were significantly associated with bone graft failure during the first year. The diagnosis of malignant disease (P = .006), the use of sternocleidomastoid muscle (SCM) flaps for soft tissue augmentation (P < .001), longer duration of suction drainage (P = .001), and the presence of postoperative recipient site complications (P = .013) were found to be significant predictors of graft survival time in the proportional hazard regression model. CONCLUSIONS: The analysis of parameters associated with bone graft outcome may aid in surgical decision making and help improve the likelihood of a successful result in the future.

Adolescent↗

Placement of endosseous implants in children and adolescents with hereditary ectodermal dysplasia.

OBJECTIVE: The purposes of this investigation were to study the feasibility of placing endosseous implants in children and adolescents with ectodermal dysplasia and to assess the position and stability of such implants during growth. This article reports on 6 subjects with long-term follow-up. Study design. A prospective study was commenced in 1991. Patients with hereditary ectodermal dysplasia who were over the age of 5 years and who presented to the University of California San Francisco Ectodermal Dysplasia Clinic for dental treatment were included and maintained in the study. In each case, clinical and radiographic records were obtained before treatment, immediately after implant placement, at delivery of the prosthesis, and subsequently at yearly intervals. Six subjects are reported, 4 as members of the prospective study group and 2 who had been treated before the study began. RESULTS: A total of 41 implants (19 maxillary, 22 mandibular) were placed. The average follow-up after implant placement was 7.8 years (range, 6-11 years), and the average time since restoration was 6 years (range, 5-10 years). Forty implants successfully integrated and have been restored. There was no evidence that implant placement or prosthetic rehabilitation resulted in restriction of transverse or sagittal growth. One mandibular implant, placed in a partially dentate 5-year-old, became submerged because of adjacent alveolar development and required placement of a longer abutment. Four maxillary implants placed in a partially dentate 7-year-old also became submerged and required prosthetic revision and the placement of longer abutments. CONCLUSIONS: This preliminary report suggests that endosseous implants can be successfully placed and can provide support for prosthetic restoration in patients with hereditary ectodermal dysplasia. However, vertical dentoalveolar growth results in submergence of the implant relative to the adjacent natural dentition when implants are placed adjacent to erupting permanent teeth.

Adolescent↗

State of the art in oral and maxillofacial surgery: treatment of maxillary hypoplasia and anterior palatal and alveolar clefts.

As the new millennium approaches, it seems appropriate to look back at where we have been and where we are going with the care of patients with facial deformities. None of us can deny that although changes have been made, many current treatment modalities are no more than modifications of old techniques. We are, however, poised to make dramatic improvements in the management of facial abnormalities as we enter the new century and millennium. Biotechnology, genetic manipulation, and new surgical technology will become pervasive, and perhaps we will move from "modification" of the old into a completely new era of therapeutic approaches to the care of dentofacial deformities. "Opportunities multiply as they are seized" (from Sun Tzu), and the time of opportunity is approaching. This review will attempt to look at the state of the art in cleft care and in oral and maxillofacial surgery: where we have been and where we are going. It will be clear that there is overlap between specialties and that these overlaps will become greater as new regimens in the care of facial deformities come to the forefront.

Alveolar Process↗

Neurosensory deficit and functional impairment after sagittal ramus osteotomy: a long-term follow-up study.

PURPOSE: This study evaluated persistent neurosensory deficit (NSD) and functional sensory deficit (FSD) after mandibular bilateral sagittal split osteotomies (BSSO) and their association with patient age at time of operation and eight additional variables. PATIENTS AND METHODS: Eighty-five patients more than 2 years post-BSSO were identified and stratified by age: group 1, 10 to 19 years (n=16); group 2, 20 to 29 years (n=24); group 3, 30 to 39 years (n=30); group 4, older than 40 years (n=15). Mean mandibular advancement, incidence of "bad split," excessive intraoperative bleeding, nerve manipulation, removal of third molars, use of rigid fixation, simultaneous mandibular procedures, and associated systemic disease were documented for each group. A questionnaire modified from Zuniga was used to document the presence of persistent (2 years or longer) NSD and FSD. Statistical analysis was performed to determine differences between groups. Logistic regression was used to evaluate each variable and determine its association with persistent NSD and FSD. RESULTS: Persistent NSD by age was: group 1, 81%; group 2, 46%; group 3, 73%; group 4, 87%. The trend of increasing persistence with increasing age was not significant (P=.248). However, persistent FSD with increasing age was highly significant (P=.003). The incidence of FSD in group 4 was statistically greater than in the other groups (P < .001; P < .001; P=.004, respectively). Logistic regression identified patient age and "bad splits" as associated with FSD (P=.003; P=.015, respectively). CONCLUSIONS: The incidence of persistent FSD more than 2 years post-BSSO increases with increasing age in a predictable and highly significant manner. Presurgical counseling should address this issue. FSD is also significantly associated with "bad splits." No other variables were found to be significant.

Adolescent↗

Delayed implantation of demineralized bone powder after local irradiation in rats.

Previous studies have shown that osteoinduction is inhibited when demineralized bone powder (DBP) is implanted within 48 hours of local irradiation (i.e., when the acute effects of radiation injury are present). This study sought to determine whether normal osteoinduction can proceed if the implantation of DBP is delayed until 21 days postirradiation. At 21 days, the acute effects of radiation injury are likely to have subsided, but the long-term effects have not yet appeared. Twenty-eight-day-old rats were administered a radiation dose of either 7 or 20 Gy over a localized area of one thigh. The contralateral, nonirradiated thigh served as a control. Demineralized bone powder was subcutaneously implanted 21 days later. Subcutaneous pellets were retrieved at various intervals thereafter (up to Day 45) and were histologically graded for evidence of osteoinduction. No difference in osteoinduction was detected at any time interval in pellets from the 7-Gy-treated sites, compared with controls. Pellets from the 20-Gy-treated sites, however, demonstrated significantly a lower osteoinductive response at each interval. These latter pellets showed small scattered areas of osteoinduction and reduced formation of marrow elements. Thus, although osteoinduction proceeds normally when the implantation of DBP is delayed for 21 days after irradiation with 7 Gy, this is not the case when 20 Gy are administered. Given the absence of gross impairment of tissue vascularity in irradiated sites, it is possible that inhibition of osteoinduction after higher doses of radiation results from permanent damage to mesenchymal precursor cells.

Animals↗

Staging of internal derangements of the TMJ with magnetic resonance imaging: preliminary observations.

Although MRI has been reported to be accurate in diagnosing displaced TMJ menisci, it has not been used to characterize the condition of the meniscus. A staging system of internal derangement of the TMJ using MRI signal characteristics and morphology of the meniscus is presented. A normal meniscus has the appearance of a small "drumstick" and is positioned superiorly on the mandibular condyle. It produces a small amount of intermediate signal on the MRI. A grade 1 displaced meniscus has normal shape and signal; a grade 2 meniscus has normal shape and absent signal; a grade 3 meniscus has abnormal shape and absent signal. There was a significant correlation between meniscus grade and chronicity of symptoms, severity of pain, and presence of degenerative joint disease in 62 joints (39 patients).

Adolescent↗

Mitogenic response of cells in culture to demineralized bone matrix.

In this study the mitogenic effect of demineralized bone powder (DBP) on cells in tissue culture was evaluated. The cells studied have osteoblastic properties. At a DBP concentration of 100 micrograms/well, rat osteosarcoma cells (ROS) 17/2.8 cells, ROS 24/1 cells, and periosteal fibroblasts (POF) all showed a significant increase in proliferation in comparison to controls. The peak effect was on day two for ROS 17/2.8 (125% of control), on day three for ROS 24/1 (139% of control), and on day four for POF (145% of control). The results indicate that this in vitro system may be useful for evaluating the osteoinductive activity of DBP preparations.

Animals↗