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Sung-Kiang Chuang

Publications and source records attributed to Sung-Kiang Chuang.

10 recordsLinked to original sources
PubMed2006

Microscopic changes in the condyle and disc in response to distraction osteogenesis of the minipig mandible.

PURPOSE: Unilateral mandibular distraction osteogenesis (DO) has been shown to cause gross changes in the mandibular condyle and articular disc. The purpose of this study was to correlate histologic findings with these gross changes in a minipig distraction model. MATERIALS AND METHODS: Semiburied distractors were placed via submandibular incisions in 15 minipigs. Two unoperated animals served as controls. The protocol consisted of 0-day latency and rates of 1, 2, or 4 mm/day for a 12-mm gap. After the minipigs were killed (at 0, 24, or 90 days), ipsilateral and contralateral condyles and discs were harvested, decalcified, prepared for standard paraffin embedding, and evaluated to determine changes in 1) morphology and thickness of the articular cartilage and subchondral bone and 2) morphology of the disc. RESULTS: In control animals, there were no degenerative changes in the articular cartilage and underlying condylar bone; there were no significant differences in the mean articular cartilage thickness. The temporomandibular joint discs were normal. In experimental animals, distracted condyles showed increasing degenerative changes and mean articular cartilage thickness as the DO rate increased. The discs were thinner. These changes were present, but to a lesser degree, in the contralateral condyles. After 90 days, degenerative changes in the condyles and discs were reduced, after remodeling, except in the 4 mm/day DO group. CONCLUSIONS: Histologic changes in the condyles and temporomandibular joint discs in response to mandibular DO correlated with previously reported gross changes. These changes were greater at higher distraction rates and remodeling back to normal occurred in mandibular condyles distracted at 1 mm/day.

Animals↗
PubMed2004

Dentoalveolar reconstructive procedures as a risk factor for implant failure.

PURPOSE: Dentoalveolar reconstructive procedures (DRPs) are commonly used to enhance deficient implant recipient sites. It is unclear, however, if these procedures are independent risk factors for implant failure. The specific aim of this study was to assess the use of DRPs as a risk factor for implant failure. MATERIALS AND METHODS: To address the research aim, we used a retrospective cohort study design and a study sample derived from the population of patients who had one or more implants inserted between May 1992 and July 2000. The main predictor variable was the use of DRPs, such as external or internal sinus lifts, onlay bone grafting, or guided-tissue regeneration with autogenous bone grafts or autogenous bone graft substitutes, to enhance the recipient sites before implant insertion. The major outcome variable was implant failure. Appropriate descriptive, bivariate, and multivariate statistics were computed. RESULTS: The study sample was composed of 677 patients who had 677 implants randomly selected (1 implant per patient) for analysis. The overall 1- and 5-year implant survival rates were 95.2% and 90.2%, respectively. Bivariate analyses revealed 4 factors statistically or nearly statistically associated with implant failure: current tobacco use, implant length, implant staging, and type of prosthesis (P <.15). In the multivariate model, patients with DRPs did not have a statistically significant increased risk for implant failure (odds ratio = 1.4, P =.3). CONCLUSIONS: The results of this study suggest that the use of DRPs to reconstruct deficient implant recipient sites was not an independent risk factor for implant failure in either the unadjusted or adjusted analyses.

Adolescent↗
PubMed2003

A comparison of 2 consultation and treatment strategies to manage impacted third molars.

PURPOSE: This study compares the postoperative complication rates of 2 strategies for the evaluation and operative management (E&M) of patients with impacted third molars (M3s). MATERIALS AND METHODS: We used a retrospective cohort study design and a sample composed of patients who had M3s extracted between 1985 and 2000. The predictor variable was the E&M strategy defined as 1) same-day surgery (SDS) in which the consultation and procedure were performed on the same day and 2) consult prior to surgery (CPS) in which the consultation and procedure were separated in time by more than 24 hours. The outcome variable was postoperative complications. Descriptive and bivariate statistics were computed and a multivariate model was developed to measure the relationship between E&M strategies and postoperative complications. RESULTS: The sample was composed of 5,993 patients (mean age, 23.7 years; 61% female), and 1,556 patients (26%) were classified as having SDS. Overall, 36% of patients reported one or more postoperative complications. Variables included in the multivariate model were E&M strategy (SDS or CPS), age, gender, number of M3s removed, tobacco exposure, and type of anesthesia. Based on the results of the multivariate model, SDS was not associated with an increased risk for postoperative complications (P =.08). CONCLUSIONS: Optimal operative management of M3s would minimize the number of visits, maximize operator efficiency, and minimize morbidity. In comparison with CPS, SDS minimizes the number of patient visits without an increased risk for complications.

Adult↗
PubMed2003

Meta-analysis of periodontal disease and risk of coronary heart disease and stroke.

OBJECTIVE: The purpose of this study was to analyze published studies and abstracts in order to provide a quantitative summary of periodontal disease as a risk factor for cardiovascular disease and to explore the possible causes for conflicting results in the literature. STUDY DESIGN: We searched all published literature on the Medline literature search engine since 1980. An additional search was performed with bibliographic citations from each article. Nine cohort studies (8 prospective and 1 retrospective), in which relative risks (RRs), CIs, and P values were reported or could be calculated were included. Four researchers independently extracted RRs, CIs, and P values from each study and evaluated the degree of confounding adjustment. The combined result was calculated with weighted average, and sources of disparity were tested with regression analyses. RESULTS: The summary RR was 1.19 (95% CI, 1.08 1.32), indicating a higher risk of future cardiovascular events in individuals with periodontal disease compared with those without. In an analysis stratified to individuals of </=65 years of age, the RR was 1.44 (95% CI, 1.20 to 1.73). When the outcome was restricted to stroke only, the RR was 2.85 (95% CI, 1.78 to 4.56). In the metaregression analysis, the effects of residual confounding caused an overestimate of the results by 12.9% and, with a proxy for periodontal disease, caused an underestimate of 29.7%. CONCLUSIONS: Periodontal disease appears to be associated with a 19% increase in risk of future cardiovascular disease. This increase in RR is more prominent (44%) in persons aged </=65 years. Although the increment of risk between subjects with or without periodontal disease in the general population is modest, at around 20% because nearly 40% of population has periodontal disease, this modest increase may have a profound public health impact.

Adult↗
PubMed2002

Risk factors affecting dental implant survival.

Given the predictability of dental implant success, the attention of the scientific community is moving from descriptions of implant success toward a more detailed analysis of factors associated with implant failure. The purposes of this study were (1) to estimate the 1- and 5-year survival of Bicon dental implants and (2) to identify risk factors associated with implant failure in an objective, statistically valid manner. To address the research purposes, we used a retrospective cohort study design and a study sample composed of patients who had one or more implants placed. The predictor variables were grouped into the following categories: demographic, health status, anatomic, implant fixture-specific, prosthetic, perioperative, and ancillary variables. The major outcome variable of interest was implant failure defined as implant removal. Overall implant survival was estimated using the Kaplan-Meier analysis. Risk factors for implant failure were identified using the Cox proportional hazard regression models. The study sample was composed of 677 patients who had 677 implants randomly selected for analysis. The overall 1- and 5-year survival of the Bicon implant system was 95.2% and 90.2%, respectively. After adjusting for other covariates in a multivariate model, both tobacco use (P = .0004) and single-stage implant placement (P = .01) were statistically associated with an increased risk for failure. The results of these analyses suggest that the overall survival of the Bicon dental implant is comparable with other current implant systems. In addition, after controlling for covariates, we identified 2 exposures associated with implant survival, tobacco use and implant staging. Of interest, both of these exposures are under the clinician's control.

Adolescent↗
PubMedDate not supplied

Complications of dental implants: identification, frequency, and associated risk factors.

PURPOSE: This study sought to identify the types, frequencies, and risk factors associated with complications following placement of dental implants. It was hypothesized that one or more factors could be identified that are associated with an increased risk for complications and may be modified by the clinician to enhance outcome. MATERIALS AND METHODS: A retrospective cohort study design was used that included patients who received Bicon implants (Bicon, Boston, MA) between 1992 and 2000. Predictor variables were grouped into demographic, medical history, implant-specific, anatomic, prosthetic, and reconstructive categories. Complications were grouped into inflammatory, prosthetic, operative, and major or minor categories. Cox proportional hazards regression models were developed to identify risk factors for complications. RESULTS: The sample was composed of 677 patients. The overall frequency of implant complications was 13.9% (10.2% inflammatory, 2.7% prosthetic, 1.0% operative), of which 53% were minor. The multivariate Cox model revealed that smoking, use of 1-stage implants, and reconstructive procedures were statistically associated with an increased risk for overall complications (P < or = .05). The median duration of follow-up was 13.1 months (range 0 to 85.6 months). DISCUSSION: A lower frequency of complications was found compared to mean frequencies calculated from past reports. Investigations examining the influence of smoking and reconstructive procedures on implant complications are recommended. CONCLUSION: Of the 3 factors associated with an increased risk for complications, tobacco use and implant staging may be modified by the clinician to enhance outcome.

Adolescent↗
PubMedDate not supplied

Survival estimates and risk factors for failure with 6 x 5.7-mm implants.

PURPOSE: Short dental implants facilitate prosthetic restoration in the setting of limited alveolar bone height. The study objectives were to (1) estimate the 1-year survival of Bicon 6 x 5.7-mm implants, (2) compare the 1-year survival of 6 x 5.7-mm implants with that of non-6 x 5.7-mm implants, and (3) identify risk factors associated with implant failure. MATERIALS AND METHODS: A retrospective cohort study design was used. The sample was composed of patients who had received at least one 6 x 5.7-mm implant. Predictor variables were categorized as demographic, health status, anatomic, implant-specific, prosthetic, perioperative, and reconstructive. The outcome variable was implant failure, defined as explantation. Appropriate descriptive, bivariate, and multivariate survival statistics were computed. RESULTS: The sample was composed of 35 patients in whom 172 implants had been placed (45 of which were 6 x 5.7-mm). The 1-year survival rates for 6 x 5.7-mm and non-6 x 5.7-mm implants were 92.2% and 95.2%, respectively (P = .76). After adjusting for covariates in a multivariate model, implant size was not associated with failure (P = .95). DISCUSSION: The comparable survival estimates for 6 x 5.7-mm implants and non-6 x 5.7-mm implants in this study suggested that 6 x 5.7-mm implants can become osseointegrated and bear a functional load after placement. CONCLUSIONS: The survival of 6 x 5.7-mm implants was comparable to that of non-6 x 5.7-mm implants.

Dental Implants↗
PubMedDate not supplied

Changes in crestal bone levels for immediately loaded implants.

PURPOSE: The authors' objective was to measure crestal bone level change in subjects with immediately loaded implants and to identify risk factors associated with changes in bone level. MATERIALS AND METHODS: A retrospective cohort study design was used. The sample comprised subjects who had had endosseous implants placed and immediately loaded between July 2001 and July 2003. Demographic, health status-related, anatomic, implant-specific, prosthetic, and surgical variables were examined. The primary outcome variable was change in crestal bone level over time. Appropriate uni-, bi-, and multivariate statistics were computed. RESULTS: The sample comprised 174 subjects who received 347 immediately loaded implants. The mean duration of radiographic follow-up was 6.9 +/- 4.0 months, respectively. Mean changes in radiographic bone level were -0.5 mm and -0.6 mm on the mesial and distal surfaces, respectively, after a mean of 6.9 months of radiographic follow-up. Using least squares methods, it was estimated that radiographic bone levels would be -1.0 mm and -0.8 mm on the mesial and distal surfaces, respectively, at 12 months. The multivariate model revealed that radiolucency at or adjacent to implant site was associated with an increased risk of crestal bone loss (odds ratio, 1.88; 95% CI, 1.00 to 3.60). Twelve months after placement, 92.5% of implants had had < or = 1.5 mm of crestal bone loss. DISCUSSION: The results of this study were comparable to the results of other studies comparing immediate loading to delayed loading. Further research to estimate long-term changes in crestal bone loss and to identify risk factors for bone loss with immediate loading is recommended. CONCLUSION: This study suggests that crestal bone level changes with immediately loaded implants were within the recommended range for 92.5% of the evaluated implants. The mandible showed a higher risk for crestal bone loss compared to the maxilla.

Adolescent↗
PubMedDate not supplied

Maxillary sinus augmentation as a risk factor for implant failure.

PURPOSE: The investigators sought to determine whether maxillary sinus augmentation (MSA) was an independent risk factor for implant failure. MATERIALS AND METHODS: Using a retrospective cohort study design, the investigators enrolled a sample composed of subjects having 1 or more implants placed in the posterior maxilla. The primary predictor variable was MSA status at the time of implant placement (MSA present or absent). MSA consisted of a lateral window (external) or an osteotome (internal) procedure. The outcome variable was implant failure defined as implant removal. Demographic, health status, anatomic, implant-specific, abutment-specific, prosthetic, and perioperative variables were also examined. Overall implant survival was estimated using Kaplan-Meier analysis. Risk factors for implant failure were identified using Cox proportional hazard regression models. RESULTS: The sample consisted of 318 patients and 762 posterior maxillary implants. The mean duration of follow-up was 22.50 +/- 19.06 months. The 5-year survival rates for implants in the ungrafted and grafted posterior maxilla were 88.0% and 87.9%, respectively (P = .08). After adjustment for covariates, MSA status was not an independent risk factor for implant failure (P = .9). Tobacco use (P < .001), implants replacing molars (P < .001), and 1-stage implants (P < .001) were statistically associated with an increased risk for implant failure. DISCUSSION: MSA status was not associated with implant failure risk. This finding may be subject to selection bias, as successful MSA was requisite prior to implant placement. CONCLUSION: MSA status was not associated with an increased risk for implant failure. Of the 3 factors associated with an increased risk for failure, tobacco use and implant staging may be modified by the clinician to enhance outcome.

Dental Implants↗