Root canal re-treatment with gutta percha - which techniques influence success?

OBJECTIVE: A systematic review and meta-analysis of the literature was carried out assessing the success rate of root canal retreatment using gutta percha. DATA SOURCES: Four of the largest databases were used to identify existing literature with no date or language restrictions. PubMed, Cochrane, ScienceDirect, Scopus and other additional sources were searched. Grey literature was also reviewed. STUDY SELECTION: Two authors, with Master's degrees in endodontics and with extensive university teaching experience, were selected to screen the databases to identify suitable studies. In case the authors were not able to agree during the study selection process, a third investigator was consulted. Specific inclusion and exclusion criteria were outlined and adhered to in the study selection. Two randomised controlled trials, seven single arm prospective studies and one single arm ambispective study published before the 10th of December 2022 were included. These studies evaluated the success of root canal re-treatment, obturated with gutta percha with at least a 1-year follow-up. Nine of the studies were published between 1998 and 2022. Seven studies were conducted in Europe, one in North America and one in Asia. DATA EXTRACTION AND SYNTHESIS: Standard Cochrane methods to assess interval validity were used. Risk of bias in individual studies was assessed using The Newcastle-Ottawa quality assessment scale (NOS) for single-arm studies, and the Cochrane risk of bias tool (RoB2) was used for randomised controlled trials. Outcome measures were standardised as either success or failure of root canal retreatment. Success was classified into 2 different criteria: Strict criteria = absence of clinical signs and symptoms and radiographically normal periodontal ligament space; and Loose criteria = absence of clinical signs and symptoms and absence or reduction of apical radiolucency in the control radiograph. Statistical analysis was undertaken using R software and the Freeman-Turkey transformation was performed. Results were visualised using forest plots. Heterogeneity between studies was measured using the Cochrane Q test and I2 values. RESULTS: Whilst following strict criteria, the success rate of non-surgical root canal retreatment obturated with gutta percha was 71% for 1-3 years follow-up (95% CI, 0.66-0.77) and 77% for 4-5 years follow-up (95% CI, 0.67-0.86). Heterogeneity was moderate (I2 = 61.4) and low (I2 = 0.0), respectively. Factors reducing the success rate of root canal re-retreatment under the strict criteria were older patients, mandibular teeth, molar teeth, the presence of a peri-apical radiolucency, teeth with a previous radiolucency, large peri-apical radiolucency's, higher initial periapical index scores and multiple visit-retreatments. Following the loose criteria, the success rate of non-surgical root canal re-treatment obturated with gutta percha was 87% for 1-3 years follow-up (95% CI, 0.79-0.93) with significant heterogeneity across the studies (I2 = 88.5%). Factors influencing the success rate under the loose criteria were large periapical lesions >5 mm and higher initial periapical index (PAI) scores. CONCLUSIONS: Non-surgical root canal retreatment results in favourable outcomes. However, there are several factors which can result in a lower success rate: the presence and size of a periapical radiolucency, a higher initial PAI score, multiple-visit retreatments, and the size and position of the tooth.

Xylitol in toothpaste: is it effective in reducing the levels of Streptococcus mutans in high caries risk young children?

DESIGN: This study is an observational prospective longitudinal cohort study, following 102 children aged 1 to 12 months over a period of 24 months. At baseline, a dental examination was carried out to assess the number of carious lesions present using the ICDAS system, and a saliva sample was taken to assess the levels of Streptococcus mutans (SM) in saliva using the Dentocult SM saliva strip. Cohort caregivers received toothbrushing instruction and a 25% xylitol toothpaste tube for which they were instructed to use twice a day over a 3-month period, after which they returned to clinic at Pristina University to receive another tube. This process continued throughout the entire 24-month study period. At the end of the study, SM prevalence was recorded again. COHORT SELECTION: 102 children and their mothers were included in this study: 43 girls and 59 boys. At the beginning of the study, the child's mean age was 6.7 months, and at the end, 30.8 months. A random sample of 60 mothers was selected to analyse SM levels. DATA ANALYSIS: The data set was summarised descriptively using summary statistics, percentages and statistical tests. Values were expressed as a mean and standard deviation. SM prevalence comparison between baseline and endpoint was tested using chi-square statistics. RESULTS: At the baseline dental examination, the child's mean age was 6.7 (±3.7 months). At this point 59% of the 102 infants were edentulous. Caries was reported to be present in 12.4% of children. The mean ICDAS score was calculated as 0.70 (2.42 SD). When caries was present (87.6% of the 102 children included in the study), the majority of the caries experience (74.2%) was determined as at an early stage (ICAS score 1 or 2). 72.6% (n = 74/102) of children were infected with SM at baseline. 28 children had Level 1 (0) SM. 57 children had Level 2 and 3 (102-4) SM. 17 children had Level 4 SM (≥105) SM. The SM categorical distribution was statistically significant (p = 0.02). At endpoint, 53.5% (57/102) of children were SM infected. Parallel comparison of pre- and post-data sets show that there was a 19.1% reduction in SM levels overall following the introduction of the xylitol toothpaste. (p = 0.002). In the participant group with the highest SM level (Level 4), a net 12.2% reduction in SM prevalence occurred. The change in SM infection was deemed statistically significant. CONCLUSIONS: Brushing twice a day with toothpaste containing 25% xylitol shows a statistically significant decrease in SM levels. This shows a promising anticariogenic effect. Late SM colonisation is protective for future carious lesions. Xylitol can help prevent early childhood caries and early SM contamination.