Root Canal Treatment Survival Analysis in National Dental PBRN Practices.

Few studies have examined the longevity of endodontically treated teeth in nonacademic clinical settings where most of the population receives its care. This study aimed to quantify the longevity of teeth treated endodontically in general dentistry practices and test the hypothesis that longevity significantly differed by the patient's age, gender, dental insurance, geographic region, and placement of a crown and/or other restoration soon after root canal treatment (RCT). This retrospective study used deidentified data of patients who underwent RCT of permanent teeth through October 2015 in 99 general dentistry practices in the National Dental Practice-Based Research Network (Network). The data set included 46,702 patients and 71,283 RCT permanent teeth. The Kaplan-Meier (product limit) estimator was performed to estimate survival rate after the first RCT performed on a specific tooth. The Cox proportional hazards model was done to account for patient- and tooth-specific covariates. The overall median survival time was 11.1 y; 26% of RCT teeth survived beyond 20 y. Tooth type, presence of dental insurance any time during dental care, placement of crown and/or receiving a filling soon after RCT, and Network region were significant predictors of survival time (P < 0.0001). Gender and age were not statistically significant predictors in univariable analysis, but in multivariable analyses, gender was significant after accounting for other variables. This study of Network practices geographically distributed across the United States observed shorter longevity of endodontically treated permanent teeth than in previous community-based studies. Also, having a crown placed following an RCT was associated with 5.3 y longer median survival time. Teeth that received a filling soon after the RCT before the crown was placed had a median survival time of 20.1 y compared to RCT teeth with only a crown (11.4 y), only a filling (11.2 y), or no filling and no crown (6.5 y).

The bisphosphonate zoledronic acid regulates key angiogenesis-related genes in primary human gingival fibroblasts.

BACKGROUND: Osteonecrosis of the jaws is recognised as a serious complication for patients receiving bisphosphonates. The anti-angiogenic effects of bisphosphonates have been implicated in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ). The purpose of this study was to determine the effects of zoledronic acid on cultured human gingival fibroblasts in relation to the modulation of genes associated with angiogenic regulation. METHODS: Primary cultures of fibroblasts were developed from gingival tissues excised during crown-lengthening surgery from three patients. Cells were cultured with and without 30µM zoledronic acid for 6, 12 and 24h and cellular proliferation and migration investigated using CellTiter-Blue and scratch wound assays, respectively. Gene expression was determined using semi-quantitative PCR array technology that allowed the analysis of 84 pathway-focused genes known to be important in the regulation of angiogenesis. RESULTS: Zoledronic acid increased the proliferation of the gingival fibroblasts in a dose dependent manner with 12 and 24h of exposure. Scratch wounding of the human gingival fibroblasts and treatment with increasing doses and time exposure to zoledronic acid (ZA) inhibited their migration. Statistically significant increases in gene expression were found for RHOB, VEGFA, CD55 and BMP2 (p≤0.05) in response to 30µM zoledronic acid. CCL2 and IL6 genes were significantly downregulated (p≤0.05). CONCLUSIONS: The regulation of the prenylated protein RHOB in this study was consistent with the known effects of zoledronic acid on the mevalonate pathway. The down regulation of CCL2 and IL6 and the upregulation of CD55 may be associated with suppression of inflammation. An increase in VEGFA and BMP2 gene expression suggests that fibroblasts respond to zoledronic acid by producing a proangiogenic environment.