Conventional Cavity Preparation Research Articles

Effect of ultrasonic and Er,Cr:YSGG laser-activated irrigation protocol on dual-species root canal biofilm removal: An in vitro study

Abstract Aim: The aim of the study was to investigate the disinfecting efficacy of a standardized irrigating solution activated by ultrasonics or laser irradiation on mature dual-species biofilms at different root levels in vitro. Materials and Methods: Conventional access cavity preparations were done on 160 single-rooted mandibular premolar teeth with single canals. Freshly extracted oral microbial strains of Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis, and Candida albicans after biochemical confirmation were used to generate two discrete dual-species microbial inoculums. The sterilized tooth samples were randomly segregated into two groups (n = 80) and inoculated with a mixed inoculum of S. aureus + E. faecalis strains (Group 1) and S. mutans + C. albicans strains (Group 2), respectively. Following the 21-day incubation period under aerobic conditions, the infected specimens in each group were divided into four subgroups (n = 20) and subjected to experimental treatment protocols. This included a positive control (no treatment of biofilms), syringe irrigation alone with TruNatomy needle, passive ultrasonically activated irrigation with 20# Irrisafe tip, and laser agitation of irrigant with Er,Cr:YSGG laser using RFT 2 laser tip. Root canals of experimental specimens (except the control samples) are instrumented with TruNatomy rotary file system using 1:1 mixture of 3% NaOCl and 18% etidronic acid as irrigants. The quantitative assessment of reduction in viable biofilm microbes after treatment was done using colony-forming unit counts and confocal laser scanning microscopy image analysis. The obtained data were analyzed statistically with a significant level set at 0.05. Results: Laser-assisted irrigation has shown a considerably higher mean percentage reduction of microbes compared to ultrasonic agitation and the syringe irrigation showed the least microbial reduction (P = 0.001). No significant difference was noted between the three root regions of ultrasonic and laser groups (P > 0.05), whereas in the syringe groups, apical portions showed higher microbial counts compared to cervical and mid-root regions (P = 0.001). Conclusion: Erbium laser-assisted irrigation has performed superior to ultrasonic agitation against both the experimental dual-species biofilms, while the syringe irrigation showed the least microbial reduction specifically at apical root portions.

Guided endodontics versus conventional access cavity preparation: an ex vivo comparative study of substance loss

BackgroundTo compare the outcomes of conventional access cavity preparation (CONV) versus guided endodontics (GE) for access cavity preparation in anterior teeth with pulp canal calcification (PCC) regarding root canal detection, substance loss, procedural time, and need for additional radiographs.MethodsExtracted, sound human teeth with PCC (n = 108) were matched in pairs, divided into two groups and used to produce 18 models. An independent endodontist and a general dentist performed access cavity preparation under simulated clinical conditions on nine models each (54 teeth). The endodontist used the conventional technique and the general dentist GE. Time needed to access the root canals and the number of additional radiographs were recorded. Pre- and postoperative cone-beam computed tomography scans were obtained to measure substance loss. Statistical significance was tested by examining the overlap of 95% confidence intervals (CIs) between the groups.ResultsAll root canals were successfully accessed by both methods. There were no significant differences in substance loss (CI: CONV 15.9–29.6 mm3 vs. GE 17.6-27.5mm3) or procedural time (CI: CONV 163.3-248.5 s vs. GE 231.9-326.8 s). However, 31 additional radiographs were required for GE compared to none for CONV.ConclusionsFor access cavity preparation in teeth with PCC, both CONV by a specialist and GE by a general dentist produce good results in terms of substance loss and time requirements.

Evaluation of volumetric substance loss and precision in targeted endodontic re-treatment with guided versus conventional access cavity preparations: An in vitro study.

Root canal retreatment is typically viewed as an "all or nothing" approach. Whether there is periapical pathosis or not, it is advised that all restorative and obturation materials be removed from all roots. Selective root retreatment, a new therapeutic strategy, allows retreatment to be restricted to a single root or multiple roots exhibiting periapical pathosis. To address the issues, "guided endodontics," a unique guided technique for the preparation of apically extended access cavities, was introduced. In this in vitro experimental study, 22 freshly extracted two-rooted maxillary first premolars were selected and divided into two groups (n = 11). Pretreatment cone-beam computed tomography imaging of all teeth was performed. Root canal treatment was performed for all samples followed by postendodontic composite restorations with the occlusal stamp technique. Then targeted endodontic retreatment (TER) was done with the conventional method and guided method respectively. The tooth substance loss was measured and evaluated using Ez3D-i-3D-software (VATECH) and work precision was determined by calculating the dentinal loss. Statistical data analysis was done by Independent t-test for substance loss measurement and Chi-square test was used to measure the dentinal loss. TER with conventional method showed significantly higher substance loss with t = 4.591 (P < 0.05) and significantly higher dentinal loss measured in conventional method (P < 0.05). In comparison to traditional TER, TER using a customized bur and three dimensions (3D)-guide results in much less substance loss. The dentinal loss was much lower in 3D-guided approach.

Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Restored with three Different Materials

Restoration of endodontically treated teeth is one of the major challenges faced in the field of operative dentistry. In endodontically treated tooth, most part of the tooth structure is lost because of dental caries, conventional access cavity preparation and biomechanical preparation during root canal therapy. They become very weak and brittle and also more prone to fracture compared to vital teeth

Comparative evaluation of the effect of conventional and truss access cavities on remaining dentin thickness, canal transportation, and canal centering ability in mandibular molars using cone-beam computed tomography

Aim: To evaluate and compare the effect of conventional and truss access cavity preparations on remaining dentin thickness (RDT), canal transportation, and centering ability in mandibular molars using cone-beam computed tomography (CBCT). Methods: Ethical approval was obtained before the commencement of the study. Thirty extracted mandibular molars were selected, disinfected, and stored in normal saline. Preoperative CBCT scans were taken for all the samples and randomly divided into two groups. (n = 15). Group A; Conventional access preparation group; Group B; Truss access preparation group. Cleaning and shaping were performed with the mesiobuccal canal of all the samples. Postoperative CBCT scans were compared with preoperative CBCT scans to evaluate the RDT, canal transportation, and canal centering ability in mandibular molar with conventional and truss access cavity preparation. Results: Data obtained from CBCT were analyzed by independent sample t-test with the P < 0.05 and found that RDT was higher in Group A as compared to Group B at the 3 and 9 mm levels, whereas it was higher in Group B at 6 mm level in both the mesial and distal side, but it was statistically insignificant at 3, 6, and 9 mm level. Canal transportation was higher in Group B than in Group A, but it was statistically insignificant at 6 and 9 mm levels but statistically significant at 3 mm. Canal centering ability was higher in Group A than in Group B, but it was not statistically significant at 3, 6, and 9 mm levels. Conclusion: Regarding RDT and canal centering ability, there is no statistically significant difference at all levels. Both groups present a statistically significant difference at 3 mm from the apex when comparing canal transportation. This suggests that conventional access cavity preparation is better than truss access preparation to maintain original canal anatomy.

Bond strength of conventional versus modified methods for Class IV restorations in primary incisors: An in vitro study.

Background. Aesthetic restorations of severely decayed anterior primary teeth are challenging due to the small size of the teeth and the large pulp chambers. Therefore, this study evaluated and compared the tensile and shear bond strengths of conventional versus modified methods (slot technique) of Cl IV restorations in primary incisors. Methods. A total of 120 extracted intact maxillary primary central and lateral incisors were divided into two groups. In group A, conventional Cl IV cavities were prepared. In group B, after conventional cavity preparation, four and three incisal slots were prepared on the incisal edges of the central and lateral incisors, respectively. All the teeth were restored using composite resin, and then the tensile and shear bond strengths were evaluated. Results. A statistically significant increase in the tensile bond strength of restorations was recorded in the modified technique compared to the conventional method (P=0.001). Although an increase in the shear bond strengths was found in the modified method, the value did not reach a statistically significant level (P=0.158). The most frequent fracture type was adhesive in the conventional group and cohesive in the modified group, considering the tensile and shear bond strength tests. In both groups, the highest average tensile bond strength was recorded in teeth with the cohesive fracture in dentin, and the lowest average was seen in the adhesive type. Conclusions. Incisal slots could increase the tensile bond strengths of Cl IV composite resin restorations in primary teeth.

Marginal Microleakage of Glass Ionomer-Based Restorations After Conventional Cavity Preparation and Er: YAG Laser Irradiation

Purpose: This study aimed to evaluate the microleakage of glass ionomer restorations (GIC) in Class V cavities prepared with both conventional and Er: YAG laser techniques. Methods: Twenty teeth were used. Standard Class V cavities (4mm wide,3m high,3mm deep) were prepared on the buccal and lingual surfaces of teeth. All teeth were randomly divided into four groups. In Groups II and IV, cavities were prepared by Er: YAG laser, and in Groups I and III cavities were conventionally prepared with a diamond bur. Groups I and II were then restored with conventional GIC (Ketac,3MEspe, U.S.A.).Groups III and IV were restored with high viscosity GIC with resin coating (EQUIA, GC, Tokyo, Japan). Specimens were stored in distilled water at 37°C for 24h. Teeth were then subjected to thermo-cycling (500 cycles,5°C-55°C). All teeth were exposed to 50.000 cycles in a chewing simulator. Specimens were stained with 0.5% aqueous basic fuchsin dye and sectioned buccolingually. Dye penetration was scored under a stereomicroscope. The data were analyzed by Kruskal-Wallis One-Way ANOVA and Mann-Whitney U tests. Results: While the highest microleakage scores were observed in the group prepared with Er: YAG laser and restored with conventional GIC the lowest microleakage scores were observed in the group prepared with Er: YAG laser and restored with high viscosity GIC. When cavities prepared with Er: YAG laser or conventional method were restored with high viscosity GIC, no statistically significant difference was found between them (p&gt; 0.05). Conclusion: High viscosity GIC can be preferred as a restorative material in the restorations of Class V cavities prepared using both conventional and Er: YAG lasers.

Micro-CT Study of the In Vivo Accuracy of a Wireless Electronic Apex Locator

IntroductionThis study aimed to compare the in vivo accuracy of Wirele-X and RootZX II electronic apex locators (EALs) in determining the position of the major foramen using micro–computed tomography (micro-CT) as the analytical tool. MethodsEleven vital teeth planned for extraction from 5 patients were used. After conventional access cavity preparation, root canals were flared and negotiated up to the apical third with sizes 08 and 10 K-files followed by irrigation with 2.5% NaOCl. K-type files were used to determine the working length of the selected canals using Root ZX II and Wirele-X apex locators until their numeric displays read “0.0.” After fixing the silicon stop to the file, teeth were extracted and imaged in a micro-CT device using a double-scan protocol. Image stacks, with and without the file in the root canal, were then co-registered and the measurement error calculated as the absolute difference between the tip of the file and the major foramen. Positive and negative values were recorded when the file tip was detected beyond or short of the major foramen, respectively. Accuracy was determined on stable measurements within ± 0.5 mm when the file tip did not extend beyond the major foramen. The χ2 test was applied to compare the ability of the EALs to detect the position of the major foramen, and the t test for dependent variables was used to verify differences in the 2 measurements obtained in each tooth. Significance level was set at 5%. ResultsWithin a tolerance level of ± 0.5 mm, no significant differences were observed between the tested EALs regarding the absolute distance values (P = .82) or in their ability to detect the position of the major foramen (χ2 = 0.2588; P = .6109). The accuracy of the Root ZX II and the Wirele-X apex locators within ± 0.5 mm were 81.8% and 90.9%, respectively. ConclusionsRoot ZX II and Wirele-X performed similarly regarding the in vivo detection of the major foramen. Using strict criteria, the accuracy of the Root ZX II and the Wirele-X apex locators were 81.8% and 90.9%, respectively.

Present status and future directions - Guided endodontics.

Luxation injuries and other stimuli may lead to a pulp canal obliteration (PCO). Even though the apposition of tertiary dentine is a sign of a vital pulp, in some cases root canal treatment is indicated in the long term due to apical periodontitis or pulpitis. Depending on the extent of PCO, root canal treatment may be challenging even for experienced and well-equipped endodontic specialists. The 'guided endodontics' (GE) technique was introduced 6years ago as an alternative to conventional access cavity preparation for teeth with PCO and apical pathosis or irreversible pulpitis. Using three-dimensional radiological imaging such as cone-beam computed tomography and a digital surface scan, an optimal access to the orifice of the calcified root canal can be planned virtually with appropriate software. GE is implemented either with the help of templates analogous to guided implantology (= static navigation) or by means of dynamic navigation based on a camera-marker system. GE has emerged as a field of research in the last 6years with very promising laboratory-based results regarding the accuracy of guided endodontic access cavities for both static and dynamic navigation. Clinical implementation seems to provide favourable results, but the evidence is mainly based on numerous case reports and a few case series. This narrative review aims to provide an update on the present status of GE and to identify relevant research areas that could contribute to further improvements of this technique.

Comparison of clinical performance of newer chemo-mechanical caries removal system and conventional cavity preparation technique in children

Objective: The study was aimed to compare the clinical performance of newer chemo-mechanical caries removal system and conventional cavity preparation technique in children. Study Design: Forty primary molars or first permanent molars of twenty children between the age groups of seven to ten years were selected randomly and divided into two groups of twenty teeth each: Group I was treated by the mechanical method and Group II with Brix 3000 gel method. The efficacy, time taken, and the pain threshold were evaluated during the caries removal by Ericson D et al. scale, stopwatch and modified visual analog scale, respectively. The preferred choice of treatment was assessed using a questionnaire. Results: The comparison between the time taken by the two methods showed a significant difference (P &lt; 0.05). The caries removal efficacy indicated a significant difference as well ( P &lt; 0.05). The pain rating results indicated a notable difference in the mean Visual Analogue Scale score (P = 0.001). The comparison between the two choices of treatment indicated a significant difference at p≤0.05. Conclusion: It was concluded that airotor was efficient in caries removal and while Brix 300 had lower pain rating and better patient acceptance.

Evaluation of the Effect of Cavity Preparation Using Er,Cr:YSGG Laser on Microleakage of Class V Composite Restorations

Background: The application of laser in dentistry for medical purposes such as caries removal, preparation of restorative cavities, and dental surface treatment for more effective bonding of restorative materials to the tooth has been significant. The present experimental study aimed to evaluate the effect of cavity preparation on microleakage by using erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) lasers, and to compare it with the effect of bur on microleakage in class V composite restorations. Methods: In this experimental study, 20 intact human premolar teeth were randomly divided into 2 equal groups according to the cavity preparation technique: G1: laser cavity preparation (LCP) using a Er,Cr:YSGG laser (Bio Lase, USA), and G2: bur cavity preparation (BCP). Standard class V cavity was prepared on both lingual and buccal surfaces in two groups. The samples underwent thermocycling for 3000 times (5-55ºC) and were immersed in a methylene blue 2% solution for 24 hours. After buccolingual sectioning from the middle of the restoration, a stereomicroscope with 20 x magnification was used to measure the penetration rate of the dye and to determine the score for microleakage. Data were analyzed using SPSS (version 16) software and Mann-Whitney U test (α=5%). Results: According to the study results, the minimum and maximum microleakage values were observed in the occlusal and gingival margins, respectively, which were identically for both groups. Comparing two groups (BCP and LCP) revealed that there was no significant difference between them in terms of microleakage values at the occlusal and gingival margins (P&gt;0.05). Conclusions: It was concluded that cavity preparation using Er,cr:YSGG laser had microleakage values similar to those found with conventional cavity preparation (bur) method in class V composite restorations.

Clinical Evaluation of Laser Versus Conventional Cavity Preparation Methods in Primary Teeth Restorations

Purpose: To compare between laser and conventional cavity preparation techniques in children, to assess clinical presentation of bulk fill composite and high viscous glass ionomer restoration. Materials and Method: In vivo study included 20 children aged from 4-8 years using split mouth technique (a total of 40 teeth was treated). Group I: 20 teeth treated by turbine. Group II: 20 teeth treated with laser. Each group was subdivided into two subgroups. The teeth were filled with Equia forte in groups IA and IIA or filled with REVEAL HD Bulk composite in groups IB and IIB. Results: Results of the study showed that conventional technique need less time than Laser. It also showed higher mean pain score than Laser although it was not significant. Tooth materials displayed excellent clinical evaluation. Conclusion: laser minimize the onset of pain during caries removal compared with drilling. A longer treatment time was the main disadvantage of this technique. Equia, and bulk fill composite, showed acceptable clinical performance.

Effect of Hydro- abrasion versus Conventional Cavity Preparation on the Clinical Performance of Composite Resin Restoration

Aim: To evaluate the effect of hydro abrasion versus the conventional drill method of cavity preparation on the clinical performance of composite restoration over one year follow up period. Materials and methods: Twenty patients with occlusal carious lesions were selected and examined with DIAGNO cam and ICDAS visual criteria to select teeth having ICDAS Code 3 or 4. Forty lesions were randomly divided into two groups (n=20) according to the method of caries removal. Cavities were prepared by the conventional drill method in group I and by hydro-abrasion in group II. Cavities of both groups were restored by self-etch adhesive (Adper Easy Bond) and nano- filled composite (Filtek Z350XT). All restorations were evaluated after 24 hours, after 9 and 12 months according to (USPHS) criteria for retention, marginal adaptation, postoperative sensitivity, marginal discoloration, and secondary caries. Results: Mild, moderate - severe and very severe pain was recorded in group I While in group II, only mild pain was recorded in (40%) of cases. The st. analysis of the collected data related to the tested USPHS criteria revealed 100% Alpha scoring regarding retention, marginal adaptation and secondary caries in both groups throughout the study period. The gap width measured under SEM was found increased sig. by time in both groups. Marginal discoloration was observed in the two groups after nine and 12 months. Post-operative hypersensitivity was found only in group I in 100% of cases at the base line and was disappeared during the next follow up period.

A comparative survival analysis of high viscosity glass ionomer restorations using conventional cavity preparation and atraumatic restorative treatment technique in primary molars: A randomized clinical trial.

Background:This randomized clinical trial (RCT) aimed to compare the 3-year survival rates of high viscosity glass ionomer restorations (HVGIC) using conventional cavity preparation and atraumatic restorative technique (ART) in primary molars.Materials and Methods:In this RCT, 139 schoolchildren aged 6–9 years with dentinal caries in primary molars were randomly allocated to groups, i.e. the ART group and the conventional group, utilizing a random number generator. Adequate allocation concealment was done. Intervention was delivered using standard procedure and GC Fuji IX ART HVGIC was used as restorations in both the groups. Analysis was carried in 92 participants, and survival rates in both the groups were compared at 12, 24, and 36-month intervals. IBM SPSS software was utilized to analyze the time taken for the procedure and the Kaplan–Meier estimate was used to assess the survival rates. P value of 0.05 was considered statistically significant.Results:The ART took longer to complete (16.48 ± 2.02 min) versus conventional rotary instrumentation (13.15 ± 1.32 min). The conventional method was slightly superior as compared to ART; excellent survival rates (i.e. >90%) were achieved in both groups at the end of 12-month follow-up with no significant differences at the end of 24 and 36 months as evident from Kaplan–Meier estimate (P = 0.255).Conclusion:Three-year follow-up showed that GIC restorations with ART and conventional method carried out using GC Fuji IX ART HVGIC were acceptably successful, substantiating the use of ART for the primary dentition in areas with high caries prevalence and limited access to dental care.

Guided endodontic treatment of multiple teeth with dentin dysplasia: a case report

BackgroundTo report the outcome of guided endodontic treatment (GET) of a case of dentin dysplasia with pulp canal calcification (PCC) and apical periodontitis based on the use of a 3D-printed template designed by merging cone-beam computed tomography (CBCT) and surface scan data.Case presentationA 12-year old female with radicular dentin dysplasia type I (DD-1) presented for endodontic treatment. Radiography revealed PCC in all teeth and apical radiolucency in seven teeth (12, 15, 26, 31, 32, 36 and 46). Tooth 36 had the most acute symptoms and was thus treated first by conventional access cavity preparation and root canal detection. Despite meticulous technique, the distal and mesiolingual canals were perforated. The perforations were immediately repaired with mineral trioxide aggregate, and the decision was made to switch to guided endodontic treatment for the remaining 6 teeth. CBCT and intraoral surface scans were acquired and matched using coDiagnostix planning software (Dental Wings Inc.), the respective drill positions for root canal location were determined, and templates were virtually designed and 3D-printed. The template was positioned on the respective tooth, and a customized drill was used to penetrate the calcified part of the root canal and perform minimally invasive access cavity preparation up to the apical region. All root canals were rapidly and successfully located with the templates. At 1-year follow-up, clear signs of apical healing were present in all treated teeth.ConclusionsIn patients with dentin dysplasia, conventional endodontic therapy is challenging. GET considerably facilitates the root canal treatment of teeth affected by dentin dysplasia.

The current state of the art in bond strength of laser-irradiated enamel and dentin (Nd: YAG, CO2 lasers) part 1: a literature review

The present study aimed to conduct a review of the literature about the current state of bond strength of laser-irradiated dental substrates to different adhesive systems. The bond strength between the adhesive materials and dental substrates is affected by many factors such as the tooth itself, adhesive system, and pretreatment procedure of tooth surface. With the introduction of the lasers in conservative dentistry, it has become possible to remove enamel and dentin in an effective way like the conventional cavity preparation and subsurface conditioning methods. This opens a new possibility of using the lasers as an alternative to these procedures. An electronic search to identify studies was performed in the PubMed, Google Scholar, Research gate, and LIVIVO online databases. The relevant studies were conducted from 2009 to 2018. Based on the literature, the collected data varied according to the type of adhesive and resin composite used, parameters (power, energy density, pulse duration, irradiation time, and distance, cooling system), substrates, and the bond strength test methodology used. Based on the limited information and low number of studies currently available, the superiority of laser surface treatment in comparison with conventional surface treatment on bond strength could not be identified.

Clinical Evaluation of a Papain-Based Gel for the Chemo-Mechanical Removalof Caries in Children

Aim: To evaluate and compare the efficacy and acceptability of a papain based chemomechanical caries removal gel, Carie-care, against Carisolv gel and conventional air-rotor cavity preparation. Study design: This study was designed as a split-mouth, randomized controlled trial with three treatments being compared in the same subject. Materials and Methods: The study was conducted on 30 children in the age group of 8-15yrs, each having at least three permanent molar teeth with non-pulpally involved carious lesions. Each of the three teeth was randomly assigned to be treated with either Carie-care, Carisolv or high-speed cavity excavation with air-rotor. The following assessments were made for each tooth: efficacy of caries removal, cavity entrance size, cavity preparation time, pain during treatment, requirement for local anesthesia and degree of patient co-operation. Statistical Analysis: Within group and between group variances amongst the study groups were analyzed with parametric (ANOVA) and non-paramaetric (Kruskall WallisH test) methods. Students 't' test was used to test the significance of two means. Results: The rate of complete caries removal was highest in airrotor group (86.7%) and least in Carisolv group (66.7%). No changes in cavity entrance size pre- and posttreatment were observed in the CMCR groups whereas a significant increase in cavity entrance size was observed (0.65 ± 0.55) in airrotor treated teeth. Mean values of time taken for procedure were 5:38 ± 0:30(SD) mm:ss and 5:50 ± 0:27(SD) mm:ss 0:58 ± 0:09(SD) mm:ss for Carie-care, Carisolv and airrotor, respectively. None of the patients treated with Carie-care had reported pain. In Carisolv and airrotor groups, mean values of pain scores were 0.2 ± 0.41 and 1.33 ± 0.55, respectively. Patients treated with CMCR gels did not request for local anesthesia but 8 (26.7%) of airrotor treated patients had required LA. The mean value for Frankl behavior rating scale was higher for CMCR groups (3.53 ± 0.51) as compared to that for the traditional method (2.43 ± 0.50). Conclusion: Based on the results of this study, the CMCR methods were less invasive and painful and more acceptable for patients as compared to the conventional method. The only observed drawback with these methods was the lengthy procedure time. Between the two CMCR gels, Carie-care was observed to be less painful and marginally less time-consuming.

Guided Endodontics versus Conventional Access Cavity Preparation: A Comparative Study on Substance Loss Using 3-dimensional–printed Teeth

IntroductionThe aim of this in vitro study was to compare endodontic access cavities in teeth with calcified root canals prepared with the conventional technique and a guided endodontics approach regarding the detection of root canals, substance loss, and treatment duration. MethodsSix identical sets of upper and lower jaw models were produced with 3-dimensional–printed incisors that had simulated calcified root canals. Splints for guided access preparations were fabricated based on 3-dimensional surface scans and cone-beam computed tomographic data sets. Under simulated clinical conditions, 3 operators with different levels of experience prepared access cavities on each front tooth with the conventional technique and guided endodontics (8 teeth per technique and operator). Access cavities were volumetrically assessed on postoperative cone-beam computed tomographic scans. Statistical significance was tested by examining the overlap of 95% confidence intervals (CIs). ResultsCanal location was successful in 10 of 24 cases (41.7%) using the conventional technique and 22 of 24 cases (91.7%) with the guided approach. The mean substance loss of the conventional access and the guided access was 49.9 mm3 (95% CI, 42.2–57.6 mm3) and 9.8 mm3 (95% CI, 6.8–12.9 mm3), respectively. The treatment lasted 21.8 minutes (95% CI, 15.9–27.7 minutes) for the conventional technique and 11.3 minutes (95% CI, 6.7–15.9 minutes) for guided endodontics. The success of the guided approach was not influenced by the experience of the operator. ConclusionsGuided endodontics allows a more predictable and expeditious location and negotiation of calcified root canals with significantly less substance loss.

Fracture strength of teeth with access cavity preparation with operating microscope or on buccal surfaces

Objective: The present study assessed the fracture strength of teeth subjected to endodontic access cavity preparation on buccal surfaces, or with the aid of operating microscopy when compared to the conventional technique. Material and methods: Sixty mandibular incisors were split into four groups (n=15): conventional access cavity preparation (CCP); conservative (C); buccal surface (BS); and control. The canals were prepared and filled and the cavities were restored. A static compressive strength test was conducted until crown fracture. The force data were compiled and assessed statistically. Kolmogorov-Smirnov and Shapiro-Wilk tests were performed to assess normality, Levene’s test to assess variance homogeneity, the one-way ANOVA to compare fracture strength in the assessed groups. Tukey’s HSD test was used to determine whether the differences in the means were significant between the groups.Results: The experimental groups did not show any statistically significant differences in mean fracture strength (CCP = 585.65 N±107.64 N)(BS = 530.52 N±129.35 N) (C = 517.83 N±114.68 N). Conclusion: Therefore, the selection of surface or size of access cavity proposed did not influence the fracture strength of mandibular incisors when compared to conventional cavity preparation. KeywordsDental pulp cavity; Dental stress analysis; Root canal therapy.

Acceptance and efficiency of anesthesia by photobiomodulation therapy during conventional cavity preparation in permanent teeth: a pilot randomized crossover clinical study

Fear and anxiety for pain makes people avoid dental treatments. The main aim of the study was to evaluate the acceptance and efficiency of pulpal anesthesia induced by photobiomodulation (PBM) therapy, during conventional cavity preparation of decayed permanent teeth. Patients of 11–25 years old (n = 24) were included in a split-mouth and randomized crossover clinical study. Conventional cavity treatment was made in two contralateral decayed teeth of the same arch, in similar extent of caries ICDAS 4 or 5, of each patient, one under conventional local anesthesia by pharmacological agents (control group) and another under pulpal anesthesia induced by PBM therapy (PBM group). The diode laser irradiation parameters were 810 nm wavelength, CW, non-contact mode, 600 μm hand piece, 6 mm, 250 mW, 120 s (60 s buccal, 60 s lingual), 0.88 W/cm2, 106.2 J/cm2, 30 J. The Wong Baker’s faces pain scale was used for assessing the discomfort levels, whereas the acceptance was obtained by asking the preference of the patient. Data were statistically compared using the Mann-Whitney Wilcoxon’s test (p < 0.05). For laser anesthesia (PBM group), the mean discomfort valued was 1.37 ± 1.55, similar to that for injection anesthesia (control group) which was 1.25 ± 1.53 (p = 0.59), independently of the ICDAS classification. Twenty-two out of 24 patients replied that they prefer the method with the laser (91.7%). This pilot study demonstrated the clinical effectiveness and acceptance of PBM induces pulpal anesthesia for cavity preparation of decayed permanent teeth and deserves further research and development.