Influence of different laser-assisted retrograde cavity preparation techniques on bond strength of bioceramic-based material to root dentine.

The purposes of the study were to evaluate the bond strength of bioceramic TotalFill root repair material (RRM) in retrograde cavities prepared using Er:YAG and Er,Cr:YSGG laser and steel bur, and to analyze failure modes. The root canals of 30 single-rooted teeth were endodontically treated, their root-ends were resected using a diamond bur, and the teeth were randomly divided into three groups (N = 10) according to the retrograde cavity preparation technique: (1) Er:YAG laser, (2) Er,Cr:YSGG laser, and (3) steel bur. All retrograde cavities were filled with the TotalFill RRM which was prepared according to the manufacturers' instructions. Push-out test was performed using universal testing machine, and failure mode was analyzed using a scanning electron microscope. The data were analyzed using one-way ANOVA, post hoc analysis with Bonferroni correction, and Fisher-Freeman-Halton exact test (p < 0.05). In the Er:YAG-, Er,Cr:YSGG-, and steel bur-prepared cavities, mean bond strengths (MPa) were 12.76, 8.44, and 6.01, respectively. The bond strength of the TotalFill RRM to dentin was significantly higher in the Er:YAG laser compared with the steel bur-prepared cavities (p = 0.004). The bond strength was not significantly different between the Er:YAG and Er,Cr:YSGG cavities (p = 0.074) and between the Er,Cr:YSGG and bur cavities (p = 0.648). In the cavities prepared by the Er,Cr:YSGG laser and bur, the failure mode of the TotalFill RRM was predominantly mixed, then adhesive and cohesive. In the Er:YAG laser-prepared cavities, the most common failure mode was adhesive, followed by mixed type and no cohesive failure. The bond strength of the TotalFill RRM to dentin was highest in the group of retrograde cavities prepared by the Er:YAG laser.

Caries prevalence among schoolchildren in urban and rural Croatia.

OBJECTIVE: The aim of the study was to evaluate caries prevalence in a sample of schoolchildren aged 6 to 16 years from rural and urban areas in Croatia. METHODS: Using standardized World Health Organisation (WHO) criteria, the oral health status of 1,589 children (265 from rural and 1,324 from urban areas) was assessed by recording the following indices: DMFT (decayed, missing, filled permanent teeth), deft (decayed, extracted, filled primary teeth), DMFS (decayed, missing, filled surfaces - permanent teeth), defs (decayed, extracted, filled surfaces - primary teeth) and SiC (Significant Caries Index). Rural areas were Stitar and Babina Greda municipalities in Slavonia and urban areas were the cities of Zupanja (Slavonia), Zagreb and Dubrovnik. RESULTS: Half of the examined children (50.0%) had caries (D component in DMFT), with 46.0% of these being from urban and 70.2% from rural areas. The median DMFT among children was 2, 4 (rural) and 2 (urban) (p < 0.001). Among 12-year-olds, the median DMFT was 4 (rural) and 3 (urban), and mean DMFT was 3.4. The median DMFS for rural area was 5 and for urban area 3 (p < 0.001). The median deft was 1.00 for rural and 1.00 for urban, while the highest value was found among 6-year-olds at 9 in rural and 7 in urban areas. The median SiC was 4, 4 (urban) and 5 (rural). CONCLUSION: Schoolchildren from urban and rural areas in Croatia differ significantly in caries prevalence. They fall into the medium DMFT classification group according to the WHO, which indicates the need for a comprehensive oral health preservation programme.

Push-out bond strength of three different calcium silicate-based root-end filling materials after ultrasonic retrograde cavity preparation.

OBJECTIVE: The aim of this study was to evaluate the bond strength of three calcium silicate-based root-end filling materials. MATERIALS AND METHODS: The root canals of 30 single-rooted teeth were endodontically treated; their root ends were resected and root-end cavities were prepared using ultrasonic tip. The teeth were randomly divided into three groups according to the material: (1) Micro-Mega mineral trioxide aggregate (MM-MTA), (2) Biodentine, and (3) TotalFill root repair material (RRM). Push-out test was performed using universal testing machine, and failure mode was analyzed by stereomicroscope. The data were statistically analyzed using Kruskal-Wallis and Man-Whitney post hoc tests. All p values < 0.05 were considered significant. RESULTS: TotalFill RRM exhibited significantly higher bond strength (12.69 MPa) than Biodentine (9.34 MPa, p = 0.023) and MM-MTA (7.89 MPa, p = 0.002). The difference between Biodentine and MM-MTA was not significant (p = 0.447). Mixed failures were the most noted in all three groups. MM-MTA had more adhesive failures than Biodentine and TotalFill, and no cohesive failures, but without statistical significance (p = 0.591). CONCLUSION: The bond strength was the highest for TotalFill RRM. CLINICAL RELEVANCE: In order to provide a persistent apical seal, root-end filling materials should resist dislodgement under static conditions, during function and operative procedures. TotalFill RRM exhibited higher bond strength to dentin than MM-MTA and Biodentine.