Introduction: The removal of ceramic veneers is a time-consuming procedure in a dental office. Little research has been done in alternative removal techniques for ceramic veneers. The objective of this study was to evaluate the removal of feldspathic and lithium disilicate reinforced glass ceramic veneers by Er, Cr: YSGG and to measure debonding time and pulpal temperature increase during veneer removal. Methods: Fifty-seven bovine incisor teeth were prepared and divided into 3 groups. Ceramic specimens with a thickness of 0.7mm, a width of 4mm and a length of 8 mm were fabricated from feldspathic ceramic, lithium disilicate reinforced glass ceramic HT (high translucency) and lithium disilicate reinforced glass ceramic MO (medium opacity) (19 for each group). Specimens were cemented on the labial surface of incisors using resin cement. The Er, Cr: YSGG laser was applied to each specimen at 2.5 W and 25 Hz. Debonding time was measured for each specimen, and the intrapulpal temperature was detected in 3 specimens for each group. Data were analyzed via one-way analysis of variance (ANOVA) at significance level of 0.05 (α = 0.05). Results: Mean debonding time was 103.68 (26.76), 106.58 (47.22) and 103.84 (32.90) seconds for feldspathic, lithium disilicate MO, and lithium disilicate HT respectively. There was no significant statistical difference among the groups (P value = 0.96). The intrapulpal temperature increase was less than 1°C in all groups. Conclusion: Er, Cr: YSGG can successfully be used to efficiently debond feldspathic and lithium disilicate reinforced glass ceramic veneers. There was no significant difference for debonding time among these ceramic materials. During ceramic laminate veneer removal by laser irradiation, no irritating temperature rise was detected.

Purpose Integration of smartphones has overcome barriers in traditional education; this trial aimed at exploring this ubiquitous platform in oral health education. A smartphone application promoting preschooler’s oral health was designed and its effectiveness was compared with that of common oral health education delivered in paediatric dental settings. Methods This controlled clinical trial was performed on preschooler–mother dyads referring to the clinic of Tehran School of Dentistry in 2019–2020. Initially, the dyads were randomly partitioned to application intervention or common training groups. The mothers answered an interviewer-administered questionnaire on paediatric dentistry knowledge, attitude and practice regarding children’s oral health; modified plaque index (m-PI) and modified gingival index (m-GI) of children were measured. Subsequently, the smartphone application was installed for application intervention group and an educational pamphlet and verbal explanations were given to common training group. In 1-month and 3-month follow-ups, the questionnaires and clinical measurement were re-done. A generalized estimating equation (GEE) was used to investigate the effect of training methods. Results Among the participants 51 dyad attended baseline and follow-up assessments. The preschoolers mean age was 4.6 ± 1.2 years and 54.4% were girls. Both trainings improved mothers’ knowledge and practice regarding children’s oral health and reduced children’s m-PI and m-GI ( p < 0.050). The 3-month follow-up revealed a better m-GI in application intervention group ( p < 0.001). Conclusions Considering the greater improvement of paediatric gingival status in the application intervention group, it appears that smartphone applications may provide a promising tool for more prolonged impacts in children oral health care. Trial registration IRCT, IRCT20131102015238N3. Registered 28 July 2019 https://en.irct.ir/trial/40933 Supplementary Information The online version contains supplementary material available at 10.1007/s40368-022-00731-9.

This study assessed the clinical variables influencing the success of three-unit implant-supported fixed dental prostheses (ISFDPs) fabricated using either fully digital or conventional workflows. The clinical trial evaluated 10 patients requiring three-unit ISFDPs in the posterior mandible. Maxillomandibular relation records, and digital and conventional impressions were obtained from each patient using an intraoral scanner (IoS) and polyvinylsiloxane (PVS), and the frameworks were fabricated using zirconia and cobalt–chromium, respectively. A 2 µm accuracy scanner scanned the conventional master casts and standard reference models. The stereolithography (STL) files of the digital and conventional impressions were superimposed on the standard model file, and the accuracy was calculated with the best-fit algorithm. The framework adaptation and passivity were assessed using the one-screw and screw resistance tests. The time required for occlusal adjustment of both types of reconstructions, including the duration of the whole treatment, was recorded. The aesthetic appearance of ISFDPs was rated by each patient and clinician using a self-administered visual analogue scale questionnaire and the FDI World Dental Federation aesthetic parameters, respectively. The sample size was based on the power calculation, and alpha was set at 0.05 for the statistical analyses. The impression accuracy, framework adaptation and passivity, and reconstructions aesthetics did not significantly differ between the digital and conventional approaches. The total fabrication time was significantly shorter using the digital workflow. Within the limitations of this clinical study, the fully digital workflow can be used for the fabrication of ISFDPs with a clinical outcome comparable to that of the conventional workflow.

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