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Aim: The influence of different heat treatments on the mechanical properties of CAD/CAM ceramics was assessed. Methodology: A systematic search in five databases and gray literature was performed. In vitro studies providing data about the influence of various thermal treatments on the mechanical properties of CAD/CAM ceramics were included. Results: Out of 6500 articles found, 15 were included for results analysis. In the disilicate group, e.max CAD showed the best results in flexural strength (FS) and Vita Suprinity in microhardness (MH) and fracture toughness (FT). In the zirconium oxide group, Incoris exhibited better performance in FS while Razor Zirconia demonstrated superior MH and FT. Eleven studies had low and four had a moderate risk of bias (RoB). Conclusions: Both reinforced vitreous ceramics and zirconia ceramics, when subjected to high temperatures for short periods of time, significantly improve their mechanical properties. Favoring the biomechanical behavior of restorations present in the oral cavity, they are always subjected to constant changes in temperature, forces of different nature, intensity, or direction, changes in acidity, presence of moisture, etc., which make this a difficult environment for their clinical survival. [ABSTRACT FROM AUTHOR]

This study aimed to describe a support material removal protocol (SMRP) from inside the root canals of three-dimensional printed teeth (3DPT) obtained by the microcomputed tomography (microCT) of a natural tooth (NT), evaluate its effectiveness by comparing the 3DPT to NT in terms of internal anatomy and behaviour toward endodontic preparation, and evaluate if 3DPT are adequate to assess the differences between two preparation systems. After the SMRP, twenty 3DPT printed by PolyJet™ were microCT scanned before preparation and thereafter randomly assigned into two groups (n = 10). One group and NT were prepared using ProTaper Gold® (PTG), and the other group with Endogal® (ENDG). MicroCT scans were carried out after preparation, and the volume increase, volume of dentin removed, centroids, transportation, and unprepared areas were compared. For the parameters evaluated, no significant differences were found between the 3DPT and NT before and after preparation (p > 0.05), and no significant differences were found between the 3DPT PTG group and the 3DPT ENDG group (p > 0.05). It can be concluded that the SMRP described is effective in removing the support material SUP706B™. PolyJet™ is adequate for printing 3DPT. Furthermore, 3DPT printed with high-temperature RGD525™ have similar behaviour during endodontic preparation with PTG as the NT, and 3DPT can be used to compare two preparation systems. [ABSTRACT FROM AUTHOR]

The dental pulp chamber volume is a fundamental measurement in the field of endodontics, but also in forensic sciences, teaching and training, or tissue engineering. This study evaluates the precision of cone-beam computed tomography (CBCT) in comparison with computed micro-tomography (micro-CT) in evaluating the pulp chamber volume of the upper central incisors ex vivo. The intra-operator and inter-operator errors were evaluated, and the results for the two techniques were compared with those of a T-test for paired samples. The intra-operator and inter-operator errors were >0.05, indicating adequate reproducibility in each operator and no significant differences between their measurements. On the other hand, no significant differences between the two measurement techniques were found. The present results demonstrate that CBCT is a precise, feasible, and reproducible technique for the evaluation of the dental pulp chamber volume ex vivo. The results provided with this method are useful for different medical domains but also for the teaching and training of undergraduate and postgraduate students. Furthermore, the findings of this study carry significant clinical implications, as the accurate assessment of the pulp chamber volume is critical in the diagnosis and treatment of various endodontic conditions. The ability of CBCT to provide reliable 3D dental anatomy measurements can enhance the planning of endodontic treatments by allowing for a better understanding of the internal tooth morphology. Additionally, the precision and reproducibility of CBCT in assessing the pulp chamber volume can contribute to improved clinical outcomes and reduced complications during endodontic procedures. These findings further support the increasingly vital role of CBCT in modern clinical practice and underscore its value as an indispensable tool in the field of dentistry. [ABSTRACT FROM AUTHOR]

The aim of this study is to analyze the effects of different endodontic irrigants and adhesive systems on the resin bond strength of fiber post cementation. In total, 144 single-rooted, unrestored human teeth were endodontically treated and randomly divided into 12 groups according to four endodontic irrigants (distilled water as control; EDTA 17%; NaOCl 5%; chlorhexidine digluconate 2%) and three different adhesive/resin cement systems (etch-and-rinse: orthophosphoric acid, Parabond® A+B/Paracore®; self-etch: ParaBond® Non-Rinse Conditioner, Parabond® A+B/Paracore®; Universal: ClearfilTM Universal Bond/ClearfilTM DC Core Plus). Forty-eight hours after post cementation, ten teeth from each group were cross-sectioned into three discs (cervical, middle and apical regions). Thirty specimens of each group (n = 30) were submitted to a push-out test at a crosshead speed of 1 mm/min. The remaining two teeth of each group were sectioned in the same manner, and the resin–dentin interface was evaluated using scanning electron microscopy (SEM). The results were statistically analyzed with the ANOVA test and Tukey's test (p < 0,01). The adhesive protocols and post space region showed no significant effect on bond strength (p > 0.01). The combination of NaOCl 5% and ClearfilTM Universal Bond reduced the adhesive strength (p < 0.01). The NaOCl 5%, in relation to other irrigants, significantly decreased the push-out bond strength. [ABSTRACT FROM AUTHOR]

Background: Performing an appropriate Class II direct restoration is a great challenge. The correct selection of the matrix system and the elements used for its stabilization will have a great impact on the result. The aim of this study is to show a new digital method for a predictable selection of the wedge and compare it with the conventional method. Methods: Sixty patients were randomly divided into two groups. In Group 0, the wedge was selected intraoperatively by visual examination, while in Group 1 the wedge was selected preoperatively through the measurement of the cervical embrasure on the bite-wing radiography. The number of wedges used, modifications to them, and tissue damage were registered, along with the quality of the proximal contact and the marginal adaptation. Results: Student's t-test revealed a statistical difference between the number of wedges used, which was higher in Group 0 (p < 0.05). Pearson Chi-square test showed that tissue damage was statistically higher in Group 0 (p < 0.05), while there was no statistically significant difference between groups in wedge modifications (p > 0.05). Group 1 revealed a higher frequency of satisfactory proximal contact and marginal adaptation (p < 0.05). Conclusions: This new technique reduces wedges waste and tissue damage and provides an adequate interproximal anatomy. [ABSTRACT FROM AUTHOR]

Aim: Several factors influence the condition of the periapical tissues associated with root filled teeth. The primary objective of this study was to retrospectively evaluate the extent and speed of bone healing of large periapical lesions associated with nonsurgical root canal treatment or retreatment. The secondary objective was to analyse the relationship between the time to complete healing when analysed using cone beam computed tomography (CBCT) and other possible predictors that affect healing. Methodology: Seventy‐nine patients were treated during the years 2013–2020 with large periapical lesions of endodontic origin (10–15 mm) as observed on intraoral periapical radiographs (IOPAR) were included. IOPAR and CBCT were available before treatment and during the follow‐up (IOPAR every 6 months and CBCT every 12 months). The volume of periapical lesions was calculated by OsiriX Lite software. Variables such as initial volume of the lesion, age, gender, type of treatment or type of root canal filling were compared to identify the differences between healed and unhealed lesions. Pearson's Chi‐square test was used for categorical variables, the t‐test for age and the Wilcoxon test for initial volume of the lesion. The association between time to healing and the variables was assessed using univariate analysis and multivariate analysis. The Wilcoxon test was used to observe the association of healing time with categorical variables and the correlation index was measured with the quantitative variables. Results: Of the 79 cases analysed, 60 lesions (76%) were completely healed as verified by CBCT in a mean healing time of 19 months, of which 60% healed fully between 12 and 18 months. Increase in age of patient and larger initial volume of the lesion were associated with a significantly longer healing time (p <.001). Gender, filling material and type of treatment did not have a significant effect on the healing process (p >.05). Conclusions: Clinicians should be aware that periapical lesions in older patients and larger areas of bone loss take longer to heal. CBCT monitoring of large periapical lesions is critical and it can help clinicians in the decision‐making process. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the in vitro performance of collagen-based sponges as a drug delivery system for intracanal antimicrobial administration. Four groups of loaded collagen-based sponges (A, 0.3% w/v amoxicillin trihydrate: potassium clavulanate (4:1); B, 0.03% w/v chlorhexidine gluconate [CHX]; C, 0.3% w/v amoxicillin trihydrate: potassium clavulanate (4:1) and 0.03% w/v CHX; D, 1% w/v amoxicillin trihydrate: potassium clavulanate (4:1) and 0.03% w/v CHX) were designed. Release kinetics were tested in vitro on cultures in Petri dishes, and the effect on bacterial biofilms was studied ex vivo on 114 extracted human single-rooted teeth. Biofilm formation was tested by scanning electron microscopy (SEM). Collagen sponges containing amoxicillin and chlorhexidine showed a time-sustained antimicrobial effect in vitro and were also able to destroy mature biofilms ex vivo. This datum was validated by means of SEM-based study of E. faecalis and S. aureus biofilms.

Cusp fractures occur frequently in endodontically treated teeth with large restorations and no cusp protection. These fractures often lead to challenging clinical decisions, such as whether to undertake complex restorative management or extraction of the affected teeth. This article reports the surgical and restorative management of two teeth with fractures exceeding the biologic width to juxtacrestal and subcrestal levels, respectively, and describes a new technique for such treatment. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to compare engine-driven instrumentation methods in relation to the appearance of defects in the walls of the root canal. Materials and methods: In total, 60 single-rooted human teeth, extracted for periodontal reasons, were conserved in Deltalab Eurotubo sterile A with 2% thymol until use. The teeth were decoronated and randomly divided into three groups (n = 20). In Group 1, canal negotiation was achieved with a size 10 K-file, followed by rotary pre-instrumentation with Pathfiles. Instrumentation with the ProTaper Universal system was carried through to a final file F4. In Group 2, the teeth were instrumented with the WaveOne Gold system according to the manufacturer's instructions. In Group 3, the teeth were left unprepared as control. After this, the canals were irrigated with 2 ml of distilled water and the teeth were conserved in distilled water. The samples were sectioned transversely before subsequent analysis on three levels. Defects were scored: 0 for no defects, 1 for cracks. Results: Reciprocating instrumentation with the WaveOne Gold Large instrument reduced by 30% the frequency of occurrence of cracks in the root canal walls in the coronal and apical thirds with respect to ProTaper F4 instrumentation (P < 0.05). There were no statistically significant differences between the systems in the incidence of cracks in the middle third. Conclusions: Instrumentation with WaveOne Gold generated fewer cracks in the coronal and apical thirds of the root canal compared with the ProTaper system. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to evaluate the ability of a solution containing fluoride to dissolve rotary instrument fragments in a simulated root canal within a maximum of 60 min. Material and methods: Eighteen M-Wire alloy rotary instruments were divided into three experimental groups according to length. An electrochemical cell was prepared in the canals with three electrodes, and file fragments were immersed in fluoride solution. A constant anodic potential of 800 mV was applied. Statistical analysis was performed using the non-parametric Wilcoxon test for paired data. Group means were compared by ANOVA for normally distributed variables, and with the Kruskal-Wallis and Jonckheere-Terpstraen tendency tests for variables that were not normally distributed. The level of statistical significance was set at P < 0.005. Results: A significant loss of weight was observed, which increased with initial fragment weight (P < 0.001). Complete (n = 3) or almost complete dissolution of 5.0 mm and 10.0 mm file fragments was achieved. The average weight reduction was 36% for 17.0 mm file fragments. The anodic potential was correlated positively with the degree of weight loss (r = 0.85, P < 0.001). Conclusion: The electrochemical method enabled significant dissolution of NiTi instrument fragments within a maximum of 60 min. [ABSTRACT FROM AUTHOR]

This study intended to help practitioners selecting the appropriate motion according to their level of expertise for glide path and complete root canal preparation of curved canals in terms of instrument fracture and preparation time. A total of 160 curved root canals (angle >30°, radius <6 mm) were allocated randomly to 4 groups: A/B for expert operators and C/D for nonexpert operators. A/C were shaped with rotary and B/D with reciprocating instruments. Preparation time was registered and compared with Kruskal–Wallis non‐parametric test and Dunn's post hoc test. Instrument separation was also registered and compared with chi‐square test. A fractographic analysis was performed with scanning electron microscopy. The use of reciprocation motions allowed nonexpert operators to avoid instrument breakage during glide path and to prepare root canals faster. Experts were equally effective in rotary/reciprocating root canal shaping and faster with rotary motions than nonexpert operators, who also fractured significantly more rotary instruments. [ABSTRACT FROM AUTHOR]