Management of giant cell lesions.
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Bone Density Conservation Agents↗
Biomedical subjects
T B Dodson
Publications and source records attributed to T B Dodson.
Multi-center randomized clinical trials in oral and maxillofacial surgery: modeling of fixed and random effects.
The multi-center randomized clinical trial (MCCT) is an important tool to evaluate treatment of rare diseases. An important and challenging analytic consideration is how to model the variability of the set of clinical centers composing an MCCT. The purpose of this paper was to demonstrate how changing the assumptions regarding the variability (fixed effect versus random effect) of the set of clinical centers may alter the results. The data for this paper were derived from a recently completed MCCT. The MCCT was designed as a prospective, randomized clinical trial comparing the stability of two techniques, i.e., wire versus rigid internal fixation (RIF), for stabilizing the mandible after bilateral sagittal split ramus osteotomy (BSSO) for patients requiring mandibular advancement. Three treatment centers were involved. The key outcome variable was change in mandibular position (B-point) over time. We developed two different analytic models by varying the underlying statistical assumptions regarding the variability of the clinical treatment centers, i.e., random or fixed effects. Analyses based on the random-effects model demonstrated no significant difference between treatment groups in terms of relapse (P=0.13). With the fixed-effects model, however, wire fixation had significantly more relapse at B-point over time than RIF (P=0.02). The results from these two sets of analyses demonstrate how changing assumptions regarding the variability of the set of clinical centers can alter the interpretation of the treatment effect. The choice of statistical modeling of the set of clinical centers is an important consideration when performing analyses of MCCTs and it is a decision that should be made prior to initiating the study.
Analysis of Variance↗
Frailty approach for the analysis of clustered failure time observations in dental research.
Because dental implant failure patterns tend to cluster within subjects, we hypothesized that the risk of implant failure varies among subjects. To address this hypothesis in the setting of clustered, correlated observations, we considered a retrospective cohort study where we identified a cohort having at least one implant placed. The cohort was composed of 677 patients who had 2349 implants placed. To test the hypothesis, we applied an innovative analytic method, i.e., the Cox proportional hazards model with frailty, to account for correlation within subjects and the heterogeneity of risk, i.e., frailty, among subjects for implant failure. Consistent with our hypothesis, risk for implant failure among subjects varied to a statistically significantly degree (p=0.041). In addition, the risk for implant failure is significantly associated with several factors, including tobacco use, implant length, immediate implant placement, staging, well size, and proximity of adjacent implants or teeth.
Analysis of Variance↗
Risk factors for dental implant failure: a strategy for the analysis of clustered failure-time observations.
This study's objective was to identify, in a statistically valid and efficient manner, the risk factors associated with dental implant failure. We hypothesize that factors exist which can be modified by clinicians to enhance outcome. A retrospective cohort study design was used. Cohort members had >or= one implant placed. Risk factors were classified as demographic, health status, implant-, anatomic-, or prosthetic-specific, and reconstructive variables. The outcome variable was implant failure. The cohort was composed of 677 patients who had 2349 implants placed. Based on the adjusted multivariate model, factors associated with implant failure were tobacco use, implant length, staging, well size, and immediate implants (p <or= 0.05). In the setting of correlated survival observations, we recommend adjusting for the correlation of the observations to provide statistically valid and efficient results. Three of the identified factors--tobacco use, immediate implants, and implant staging--potentially may be modified to enhance implant survival.
Age Factors↗
Predicting dental implant survival by use of the marginal approach of the semi-parametric survival methods for clustered observations.
The analyses of clustered survival observations within the same subject are challenging. This study's purpose was to compare and contrast predicted dental implant survival estimates assuming the independence or dependence of clustered observations. Using a retrospective cohort composed of 677 patients (2,349 implants), we applied an innovative analytic marginal approach to produce point and variance estimates of survival predictions given the covariates smoking status, implant staging, and timing of placement adjusted for clustered observations (dependence method). We developed a second model assuming independence of the clustered observations (naïve method). The 95% confidence intervals for survival prediction point estimates given the naive method were 5.9% to 14.3% more narrow than the dependence method estimates, resulting in an increased risk for type I error and erroneous rejection of the null hypothesis. To obtain statistically valid confidence intervals for survival prediction of the Aalen-Breslow estimates, we recommend adjusting for dependence among clustered survival observations.
Cluster Analysis↗
Nasopharyngeal carcinoma: clinical assessment and review of 176 cases.
OBJECTIVE: The objective of this study was to delineate salient disease characteristics and to determine factors associated with survival in a series of patients with nasopharyngeal carcinoma (NPC). STUDY DESIGN: To address our research objective, we used a retrospective cohort study design and a sample of patients who presented for evaluation and management of NPC. Demographic data, medical history, radiographic findings, staging, and histology were recorded. Treatment and follow-up information were ascertained. Survival data and descriptive statistics were calculated. Multivariate analyses identified risk factors associated with survival rates for all World Health Organization (WHO) types. RESULTS: The sample comprised 123 men and 53 women (n = 176) of which 70% were white and 23% were Asian. A neck mass was the initial symptom in 49% of patients. In 99% of cases, radiation therapy was the primary treatment mode. WHO types 1 and 3 were most common. Overall 5-year disease-free survival rate was 45.5%. Age, use of tobacco or ethanol, and number of presenting symptoms were statistically associated with decreased survival rate in WHO 1 (squamous cell) tumors. Male gender and total number of presenting symptoms were associated with decreased survival rate for WHO 2 and 3 (nonkeratinizing or undifferentiated) tumors. CONCLUSIONS: Being attuned to the presenting signs of NPC may lead to a more expedient diagnosis. The differing risk factors associated with WHO 1 tumors become clear in this predominantly white population.
Adolescent↗
Hospital course of HIV-positive patients with odontogenic infections.
OBJECTIVE: The study purpose was to compare and contrast the hospital course of patients who are human immunodeficiency virus-positive (HIV+) and human immunodeficiency virus-negative (HIV-) who were admitted to manage their odontogenic infection. STUDY DESIGN: We used a retrospective case-control study design and a sample derived from patients admitted for management of their odontogenic infections. Cases and controls were defined as patients who were HIV+ or HIV-, respectively. HIV status was determined by patient self-report. Outcome variables included admission temperature (degrees Celsius) and white blood cell count, number of fascial spaces infected, days with temperature >38 degrees C, need for intensive care, and length of hospital stay. RESULTS: The study sample consisted of 60 patients (10 HIV+ cases and 50 HIV- controls matched for age and sex) with a mean age of 32.8 +/- 6.6 years and was predominantly male (78%). Significant differences existed between patients who were HIV+ and those who were HIV- for the following variables: admission white blood cell count, number of days with maximum temperature >38.0 degrees C, and use of the intensive care unit. CONCLUSIONS: The study results suggest that patients who are HIV+ who are admitted for management of odontogenic infection have a significantly more intense hospital course than those who are HIV-. However, the overall length of hospital stay is not significantly different.
Adult↗
Kaplan-Meier analysis of dental implant survival: a strategy for estimating survival with clustered observations.
The study's purposes were to estimate dental implant survival in a statistically valid manner and to compare three models for estimating survival. We estimated survival using three different statistical models: (1) randomly selecting one implant per patient; (2) utilizing all implants, assuming independence among implants from the same subject; and (3) utilizing all implants, assuming dependence among implants from the same subject. The cohort was composed of 660 patients who had 2286 implants placed. Due to the high success rates of implants, the five-year survival point and standard error estimates varied little among the three models. Patients at high risk for implant failure (smokers) manifested greater variation in the standard error estimates among the three models, 8.2%, 4.0%, and 5.6%, respectively. To obtain statistically valid survival confidence intervals when performing Kaplan-Meier survival analyses, we recommend adjusting for dependence when there are multiple observations within the same subject.
Dental Implantation, Endosseous↗
Nutritional status of substance abusers with mandible fractures.
PURPOSE: The purposes of this study were 1) to assess the validity of patient self-report in identifying illegal substance abuse and 2) to identify nutritional deficiencies in substance abusers presenting for treatment of mandible fractures. PATIENTS AND METHODS: To address the research purposes, a prospective cohort study was conducted of patients presenting for treatment of mandible fractures. A urine drug screen was used to determine the validity of patient self-report of substance abuse. For purposes of assessing nutritional status, 2 categories of substance abusers were identified: illegal and legal (alcohol). The nutritional status was measured using various laboratory markers. RESULTS: The sample was composed of 93 subjects. Urine drug studies were available for 32 patients. Of the 22 patients who denied illegal drug use, 12 (55%) had a positive drug screen. Of the 10 patients reporting a positive history of illicit drug use, 7 (70%) had a positive urine drug screen (P = .47). A positive correlation was found between alcohol exposure and serum aspartate aminotransferase, mean corpuscular volume, and lactate dehydrogenase. Positive drug screens also were associated with increased serum ferritin levels. CONCLUSIONS: The results of this study suggest that patient self-report of illicit drug use may be unreliable. The findings also suggest that legal and illegal substance abusers presenting for treatment of mandible fractures have minimal nutritional deficiencies.
Adult↗
The effect of mandibular third molar presence and position on the risk of an angle fracture.
PURPOSE: This study assessed the relationship between the presence and position of mandibular third molars (M3) and angle fractures. PATIENTS AND METHODS: A retrospective cohort study design and a sample composed of patients admitted for treatment of mandible fractures between January 1993 and April 1998 were used. Data sources were the patients' medical records and radiographs. The predictor variables were the presence and position of M3. M3 position was grouped into 9 categories based on the Pell and Gregory classification. The outcome variable was the presence of an angle fracture. Other study variables included age, sex, race, mechanism of injury, and fracture location. RESULTS: The eligible sample was composed of 437 patients, of whom 367 had data available for analysis. Patients with M3 present had a 1.9 times (95% confidence interval = 1.2 to 2.9) greater chance of an angle fracture than patients without M3s (P = .003). There was a statistically significant variation in the risk for an angle fracture, depending on M3 position (P = .049). CONCLUSION: The study results confirm other reports that patients with M3 present have an increased risk for angle fractures. Furthermore, it also showed that the risk for an angle fracture varied depending on M3 position.
Accidental Falls↗
Special considerations for the pediatric emergency patient.
Management of pediatric maxillofacial infections and trauma continue to challenge the clinician, because both conditions are uncommon. Therefore, individual clinicians might not see enough cases to formulate systematic and consistent treatment plans. When one is evaluating pediatric maxillofacial infections, the location of infection (upper or lower face) can serve as a diagnostic aid to develop a differential diagnosis and to initiate empiric treatment. When evaluating pediatric maxillofacial injuries while implementing acute treatment measures, the clinician should also be aware of the potential for late adverse sequalae owing to alteration of growth. In the absence of controlled studies, however, growth alternation from traumatic injuries to the facial skeletal remains a plausible but unproved hypothesis.
Child↗
Head, neck, and facial injuries as markers of domestic violence in women.
PURPOSE: The diagnosis of domestic violence (DV) is difficult because of a lack of clearly defined signs and symptoms. The goal of this study was to confirm and refine the role of head, neck, and face (HNF) injuries as markers of DV. PATIENTS AND METHODS: A cross-sectional study design and a sample of female trauma patients treated in an inner-city hospital emergency room (Grady Memorial Hospital, Atlanta, GA) were used. The predictor study variable was injury location (HNF or other location). The outcome variable was traumatic origin (DV or other cause). A victim of DV was defined as a patient who gave a history of being injured by her spouse or sexual partner. Other data included age, nature of the injury (blunt or penetrating), and injury severity score (ISS). Descriptive, bivariate, and logistic regression statistical analyses were performed. RESULTS: The sample consisted of 100 injured women, with a mean age of 40+/-16.3 years and a mean ISS of 3.3+/-3.0. Thirty-four women were victims of DV. The mean age of the DV victims was 32.5+/-7.3 years, compared with a mean age of 43.9+/-18.2 year in the other-causes group (P = .001). The mean ISS for the DV victims was 3.4+/-3.0, and the mean ISS for the other-causes group was 3.2+/-3.0 (P = .65). DV victims were 7.5 (2.5 < RR < 22.9) times more likely to have HNF injuries than other trauma patients (P < .001). Age was associated with cause and location of injury. After controlling for age, location remained statistically associated with cause (P = .0002). Sensitivity and specificity of HNF injuries and DV were 91% and 59%, respectively. CONCLUSIONS: The data suggest that although HNF injuries and age were sensitive predictors of DV, they remain poor in their specificity as markers.
Adult↗
The risk of serious odontogenic infections in HIV-positive patients: a pilot study.
OBJECTIVE: The purpose of this study was to perform a preliminary test of the hypothesis that patients infected with the human immunodeficiency virus (HIV) have an increased risk for serious odontogenic infections in comparison with HIV-negative patients. STUDY DESIGN: To address the research purpose, we used a case-control study design. A case was a serious odontogenic infection requiring inpatient management. A control was a nonserious odontogenic infection that could be managed on an outpatient basis. The ratio of controls to cases was 2:1. HIV status was determined by record review. RESULTS: The sample was composed of 300 patients. Sixteen patients (5%) were HIV-positive. Overall, 37.5% of the HIV-positive patients had serious infections; this compared with 33% of the HIV-negative patients (odds ratio = 1.21; 95% confidence interval = 0.43-3.44; P = .79). CONCLUSIONS: The results of this pilot study suggest that HIV-positive patients do not have an increased risk for developing serious odontogenic infections.
Adult↗
Maxillary perfusion during Le Fort I osteotomy after ligation of the descending palatine artery.
PURPOSE: Controversy exists regarding management of the descending palatine artery (DPA) during Le Fort I osteotomy. Some surgeons advocate preserving the DPA, and others ligate the vessels. The purpose of this study was to evaluate maxillary gingival blood flow (GBF) during Le Fort I osteotomy in a sample of patients with and without ligation of the DPA. PATIENTS AND METHODS: Using a prospective randomized clinical study, we enrolled a study sample composed of 34 patients undergoing Le Fort I osteotomy. The patients were randomly assigned to either study group 1 (16) (DPA ligated) or group 2 (18) (DPA preserved). To measure maxillary GBF during the operation, we used laser Doppler flowmetry (LDF). The predictor variable was status of DPA management (ligated or preserved). The outcome variable was change in GBF over time. RESULTS: (DPA). Before ligation (or simulated ligation) of the DPA, the mean GBF for groups 1 and 2 was 11.4 +/- 8.6 and 11.9 +/- 9.4 mL/min/100 g tissue, respectively (P = .88). After ligation of the DPA in group 1, the mean GBF was 10.0 +/- 7.7 mL/min/100 g tissue. At the corresponding time in group 2 (DPA preserved), the mean GBF was 12.6 +/- 9.4 mL/min/100 g tissue. The difference in mean GBF between groups 1 and 2 was not statistically significant (P = .43). CONCLUSION: There were no statistically significant differences in mean maxillary GBF between patients having the DPA ligated and those having the DPA preserved as measured using LDF during Le Fort I osteotomy.
Adolescent↗
Percutaneous injuries during oral and maxillofacial surgery procedures.
PURPOSE: This study estimated the frequency of percutaneous injuries (Pls) to dental health-care workers during oral and maxillofacial surgery and examined the circumstances surrounding the incidents. MATERIAL AND METHODS: A self-reported, prospective study was conducted to document Pls incurred during oral and maxillofacial surgery performed on outpatients and inpatients over 1-month and 6-month periods, respectively. Among the study variables examined were the numbers of patients treated, number and types of procedures performed, duration of treatment, numbers and types of health care workers at risk, treatment setting, and number of injuries. RESULTS: Four injuries were recorded during 362 operating room procedures on 236 inpatients, for a rate of 1.1 Pls per 100 procedures (95% confidence interval: 0.3 to 2.8) and 1.7 Pls per 100 patients (95% confidence interval: 0.5 to 4.6). These four injuries occurred during 1,665 person-procedures (mean number of workers present at each procedure times the total number of procedures) for a rate of 0.24 Pls per 100 person-procedures (95% confidence interval: 0.1 to 1.0). Three injuries took place during fracture reductions; two were caused by surgical wire and the third by a needlepoint Bovie tip. One injury occurred during orthognathic surgery and involved a Woodson elevator. Residents recorded no injuries while treating 521 outpatients (0 Pls per 100 patients; 95% confidence interval: 0 to 0.6). CONCLUSION: The results support previous findings that Pls rarely occur during outpatients oral and maxillofacial surgery procedures. However, the findings suggest that operating room procedures for oral and maxillofacial surgery that use wire or involve fracture reduction may be associated with an increased risk of injury. Strategies such as using a cork or sponge to cap sharp wires or instruments, and protecting hands and fingers by double gloving, may be used to decrease the risk of Pl.
Accidents, Occupational↗
Cranial bone graft to reconstruct the mandibular condyle in Macaca mulatta.
PURPOSE: The purpose of this study was to evaluate the efficacy of cranial bone grafts to reconstruct the mandibular condyle in a nonhuman primate model. MATERIALS AND METHODS: The right mandibular condyle was resected in eight female, adult, nongrowing monkeys (Macaca mulatta) and the mandible was reconstructed with autogenous, full-thickness cranial bone harvested from the frontal area of the skull and stabilized with rigid fixation. Joint function, facial symmetry, and occlusion were evaluated preoperatively and over the course of 1 year postoperatively. The height of the bone graft was measured intraoperatively and at 1 year postoperatively. RESULTS: Seven monkeys survived for 1 year. The animals' weights were stable postoperatively. There were no statistically significant changes in maximal incisal opening or lateral excursion, as well as no statistically significant changes in facial symmetry or occlusion. On average, the total decrease in height of the graft was 0.7 +/- 0.9 mm (P = .07). CONCLUSION: After reconstruction of the mandibular condyle in Macaca mulatta, full-thickness cranial bone grafts provided a functional joint that resisted resorption. Cranial bone may therefore provide a suitable alternative to other autologous or alloplastic graft materials for reconstruction of the human mandibular condyle in nongrowing patients.
Analysis of Variance↗
Recommendations for management of trigeminal nerve defects based on a critical appraisal of the literature.
PURPOSE: Management of trigeminal nerve injuries continues to challenge oral and maxillofacial surgeons. The purpose of this review article is to apply the principles of evidence-based medicine (E-BM) to determine the optimal operative technique for managing defects involving the inferior alveolar (IAN) or lingual nerves when direct (ie, primary) repair is not feasible. METHODS: To address the research purpose, the four steps of the E-BM critical appraisal process were applied: 1) identify the clinical problem, 2) efficiently search the literature, 3) select relevant articles and apply rules of evidence, and 4) apply the findings to patient care. Parameters for the literature search included using Medline to identify English language articles, publication dates from 1986 through 1996, and studies involving human subjects. RESULTS: The studies reviewed showed that the clinical literature on operative management of trigeminal nerve injuries is sparse, preoperative and postoperative neurosensory examinations are poorly documented, and the data are derived completely from reports using case series methods. Given these limitations, the available literature suggests that 1) tension-free, primary (direct) suture repair of an injured nerve, if possible, provides optimal results; 2) if direct repair is not possible, autogenous nerve grafts should be used for acute injuries, for example, immediate nerve repair after tumor resection or at the time of acute repair after traumatic injury; and 3) if direct repair is not possible, autogenous nerve grafts or hollow conduits (entubulization) to bridge the defect are equally successful for delayed reconstruction of gaps of 3 cm or smaller. CONCLUSIONS: Based on the weakness of the current literature, recommendations for future research include 1) better standardization and documentation of sensory deficits resulting from nerve injuries and their recovery, 2) using multicenter studies to accumulate large samples of patients rapidly, 3) using case series or prospective cohort study designs to assess the value of operative management of nerve injuries, and 4) progressing to randomized clinical trials to ascertain the optimal operative management of nerve injuries.
Adolescent↗
Evidence-based medicine: its role in the modern practice and teaching of dentistry.
Evidence-based medicine is a new paradigm for clinical practice. The purpose of this article is two-fold: (1) to define and review the principles of evidence-based medicine and (2) suggest mechanisms for implementing evidence-based medicine in dental education.
Decision Making↗