Efficacy of Smear Layer Removal at the Apical One-Third of the Root Using Different Protocols of Erbium-Doped Yttrium Aluminium Garnet (Er:YAG) Laser.

Background and Objectives: Smear layer forms during cleaning and shaping can obstruct the entry of both irrigant and sealant into the dentinal tubules, resulting in the accumulation of the bacteria and their byproducts. To ensure effective adhesion and better periapical healing, it is strongly advised to remove the smear layer before proceeding with root canal obturation. This study was designed to compare the efficiency of laser-activated irrigation (LAI) in removing the smear layer and debriding the most apical third of the root canal. Materials and Methods: Sixty-five extracted human teeth with straight single roots were randomly and equally divided into four laser and one control groups. Root canals in all samples were shaped using prime size TruNatomy rotary files. During preparation, each canal was irrigated with 3 mL of 3% NaOCl and 3 mL of 17% EDTA alternately, followed by the irrigation with 10 mL of distilled water to avoid the prolonged effect of EDTA and NaOCl solutions. Final irrigation of 5 mL of 17% EDTA of the root canal was done to eliminate the smear layer and was subsequently activated by an endodontic ultrasonic tip for 20 s three times (control group), a flat-end laser tip (test groups 1 and 3) or a taper-end laser tip (test groups 2 and 4) for two cycles. The time of each cycle activation was 10 s (groups 1 and 2) or 20 s (groups 3 and 4) in which the Er:YAG laser of 2940 nm was used. The laser operating parameters were 15 Hz and 50 µs pulse duration. The samples were then split longitudinally and subjected to scanning electron microscopy (SEM). Results: The remaining smear layer at the apical part of the root canals was statistically significant between the control group and the laser groups 1 (p = 0.040) and 2 (p = 0.000). Within the laser groups, the exposed tubules count was greater in the laser with the flat tip as compared with the tapered tip (Laser 1 > Laser 2 and Laser 3 > Laser 4). Finally, no significant differences in the count of debris between the laser groups and control group were observed, except for laser 4 (p < 0.05), which had the highest count of debris. Conclusion: LAI to remove debris and smear layer at the apical third of the root canal is inferior to the current ultrasonic technique. However, when using the Er:YAG LAI, it is recommended to use a flat tip design for 10 s for two cycles to ensure maximum debridement of the apical dentin surface.

The Standard Operating Procedures in COVID-19 Pandemic for Periodontal Aerosol-Generating Procedures: A Process Audit.

OBJECTIVE: This study aims to audit the process of patient management with aerosol-generating procedure (ultrasonic scaling) while adherence to the guidelines for health care workers (HCWs) during the coronavirus disease 2019 (COVID-19). MATERIALS AND METHODS: Audits records at the Department of Periodontology at University College of Medicine and Dentistry Hospital, Lahore, Pakistan were collected (prospectively) over the period of October 1 to November 30, 2020 (1st cycle) and December 14, 2020 to February 12, 2021 (2nd cycle). The audit was divided into three components based on the guidelines: (1) physical environment, (2) patients/appointments, and (3) COVID standard operating procedures related to HCWs. RESULTS: The recommended physical layout and procedural factors, as suggested by the guidelines for dental clinics, were observed during the first cycle of audit, and discrepancy of ventilation system was fixed after the first cycle. Audit team reported the observance of fallow time three times daily, which revealed 83.3% observance of fallow time.Later in the second cycle when the extraoral high-volume air evacuator was installed, the fallow time was reduced to 15 minutes and not only five procedural slots per day were created but fallow time was also observed 100% of the time. CONCLUSION: Following the standard guidelines resulted in more efficient working environment and lesser risk for HCWs while performing aerosol-generating procedures.

In Vitro Microscopic Evaluation of Metal- And Zirconium-Oxide-Based Crowns' Marginal Fit

ABSTRACT Objective To evaluate the marginal adaptation of computer-aided designing and computer-aided machining (CAD/CAM) fabricated cobalt-chromium and zirconium-oxide-based ceramic crowns compared to those produced by a conventional method. Material and Methods The study consists of three groups; 45 crowns fabricated from cobalt-chromium (CAD-CoCr) and 45 crowns manufactured from zirconium CAD/CAM technology (CAD-Z), and 45 control (C) which consists of conventional metal-ceramic crowns. The marginal discrepancies in vertical dimensions were assessed utilizing a microscope in four surfaces (mesial, distal, vestibular, and oral) for each crown. On completion of the microscopic evaluation, multivariate analysis of variance (MANOVA) was used to study the difference in the four surfaces, considered altogether. Two-way ANOVA revealed the effect of three systems used for gap measurements of each landmark. The differences observed were considered significant at p<0.05. Results There were no differences in the four surfaces revealed by АNOVА in the three groups when considered altogether. Two-way ANOVA of each surface discovered no differences among all groups as well. Conclusion The CAD/CAM crowns revealed a comparable and satisfactory marginal adaptation compared to conventional metal-ceramic crowns.

Comparison between effectiveness of dentine desensitizer and one bottle self-etch adhesive on dentine hypersensitivity.

BACKGROUND: Dentine hypersensitivity is one of the most common chief complaints of patients observed by dentists in their practice. However, there is a lack of universal consensus over the selection of reliable treatment modality. OBJECTIVES: To compare the effectiveness between dentine desensitizer and self-etch adhesive in patients complaining of moderate to severe dentine hypersensitivity pain. METHODS: A total of 254 patients with moderate to severe dentine hypersensitivity were randomly divided into Group A (Single Bond Universal Agent) and Group B (Seal & Protect Agent) according to the treatment provided. Sensitivity was assessed by means of mechanical (probing) and evaporative (air blast) stimuli. Discomfort Internal Scale (DIS) was explained to patients. DIS scores were recorded after one minute and one month following the application of both agents. Descriptive statistics were calculated. Stratification was done to control confounder and post stratification chi-square test was also applied. RESULT: The statistically significant difference (p= 0.000) in effectiveness between the two groups was observed. The mean discomfort internal scale score at baseline, after 1 minute and after 1 month in Group A was 3.65 ± 0.60, 2.33 ± 0.64 and 0.41 ± 0.71 respectively, while in Group B, it was 3.55 ± 0.58, 2.40 ± 0.62 and 0.72 ± 0.92 respectively. Overall, 86.6% patients observed improvement in dentinal sensitivity in Group A while in Group B only 67.7% patients reported reduction in sensitivity. CONCLUSION: Self-etch adhesive significantly reduces dentin hypersensitivity, immediately after one minute of its application and is effective for a period of one month compared to desensitizing agent.

Comparison of successful outcome of pit and fissure sealants bonded with etch-and-rinse adhesive and self-etch adhesive system.

BACKGROUND: Dental caries is one of the most common diseases around the world. The newly erupted permanent posterior teeth are at great risk due to the complex occlusal morphology of pits and fissures, infraocclusion and incomplete maturation of enamel. Pit and fissure sealants are the treatment of choice in such conditions. OBJECTIVES: To compare the successful outcome of pit and fissure sealants bonded with etch-and-rinse adhesive system and self-etch adhesive systems in newly erupted permanent first molars. METHODS: This randomized clinical trial was conducted at the Fatimah Jinnah Dental Hospital from June 2017 to May 2019. Children aged between 6 to 9 years who fulfilled the inclusion criteria were recruited for this study after parents' consent. Patients were randomly divided into two groups by the lottery method. Thirty patients with 60 first molar teeth in Group A were treated with etch-and-rinse adhesive system, while the other thirty patients with 60 first molar teeth in Group B were treated with self-etch adhesive system. After adhesive placement, all children received the same fissure sealants in newly erupted maxillary and mandibular permanent first molar. Each group was clinically evaluated at 6 and 12 months follow-up visit. Modified United States Public Health Service (USPHS) criteria were used for direct clinical evaluation of successful outcomes such as sealant retention and marginal discoloration. RESULTS: Successful outcome was statistically significant in Group B compared to Group A (60% vs. 30% p= 0.020) at 12 months follow-up. Stratification analysis was performed with respect to age in which a successful outcome was not significant (p= 0.43) between groups for 6 to 7 years of age, while it was significant (p= 0.012) between groups in 8 to 9 years of age children. CONCLUSION: Self-etch adhesive system is better than etch-and-rinse adhesive system in terms of long-term sealant retention. In addition, the bonding procedure is simple with relatively short clinical application time therefore it would offer great benefit to clinicians in treating pediatric patients.

Polyetherketoneketone (PEKK): An emerging biomaterial for oral implants and dental prostheses.

Polyetherketoneketone (PEKK) is a new evolving polymeric material. The present article comprehensively reviewed an overview of various applications of PEKK in prosthodontics and oral implantology, highlighting its prospects for clinical applications. PEKK biomaterials is an elastic material with good shock absorbance and fracture resistance and present ultra-high performance among all thermoplastic composites for excellent mechanical strength, chemical resistance, and high thermal stability. Available articles on PEKK for dental applications were reviewed from January 1957 to August 2020) using MEDLINE/PubMed, Web of Science, and ScienceDirect resources. PEKK presents suitable physical, mechanical, and chemical properties for applications in prosthodontics and oral implantology. PEKK has good potential for a wide range of dental applications, including tooth restorations, crowns, bridge, endoposts, denture framework, implant-supported fixed prosthesis, and dental implants. PEKK dental implants have shown lesser stress shielding compared to titanium for dental implant applications. Further modifications and improving material properties can result in broader applications in the field of dentistry. Long term evaluations are needed as PEKK is recently applied in dentistry, and there are limited studies published on PEKK.

A Comparative Evaluation of the Effectiveness of Added Auxiliary Features, Occlusal Surface Modifications, and Reduction of Total Occlusal Convergence on the Resistance of Full Veneer Metal Crowns on a Molar Tooth with Inadequate Resistance Form: An in vitro Study.

INTRODUCTION: Single crowns or fixed partial dentures retainers usually get dislodged due to inadequate resistance form. Hence, it is prudent to evaluate features of a tooth preparation, which can prevent these failures. AIM: To evaluate the effect of auxiliary features, occlusal surface modifications, and total occlusal convergence (TOC) on the resistance of a full veneer crown. MATERIALS AND METHODS: An ivorine mandibular molar tooth was prepared with features of inadequate resistance form, i.e., 2.5 mm axial wall height and TOC of 20°. Seven auxiliary preparation features were subsequently added one by one to it. They were mesiodistal grooves, buccolingual and mesiodistal grooves, buccolingual grooves, mesiodistal boxes, occlusal inclined planes, 8° reduced TOC in the cervical aspect, and mesiodistal grooves added to 8° reduced TOC in the cervical aspect. Ten dies with their respective crowns were prepared for each group. Resistance testing of all the samples was performed on the INSTRON testing machine. RESULTS: Modification of the overtapered die preparation by reducing the TOC to 8° in the cervical 1.5 mm of the axial wall and then subsequently adding mesiodistal grooves to the reduced TOC cervically offered the greatest resistance to dislodgment statistically. CONCLUSION: For an overtapered preparation, reducing the TOC to 8° in the cervical aspect and subsequently adding proximal grooves can provide maximum resistance form.

Cytomorphometric Analysis of Inflammation Dynamics in the Periodontium Following the Use of Fixed Dental Prostheses.

Cytomorphometry is used in the sampling of biological materials and diagnostic procedures. The use of cytological studies in periodontal diseases is not well described in the literature. Our study aimed to quantitatively assess the inflammation dynamics using cytomorphometric analysis of the periodontium before and after the use of fixed dental prostheses. Following ethics approval, a total of 105 subjects were divided in 3 groups as gingivitis (n = 23), periodontitis (n = 58), and healthy periodontium (control) (n = 24). The fixed dental prostheses (crowns and fixed partial dentures) were fabricated from cobalt-chrome metal-ceramic prostheses using the conventional method (C/M-CoCr), cobalt-chrome metal-ceramic prostheses by the computer-aided design and computer-aided manufacturing (CAD/CAM) technique (C/C-CoCr), and zirconia-based ceramic prostheses by the CAD/CAM technique (C/C-Zr) among subjects with gingivitis and periodontitis. The gingival crevicular fluid (GCF) was obtained from subjects before and after the use of the prostheses. The total count of epithelial cells and the connective tissue cells or polymorphonuclear neutrophils (PMNs) in GCF were studied using cytomorphometric analysis. The Statistical Package Tor the Social Sciences (SPSS), Version 20 (IBM Company, Chicago, IL, USA) was used to analyze the results and the significance level was set at p = 0.05. The data for before and after the use of the prostheses were compared using independent t-Tests. Similarly, the results after the use of prostheses in gingivitis, periodontitis, and control in each type of prostheses were compared using One-way ANOVA with post hoc using Scheffe. The total epithelial cells and the PMNs were determined along with the epithelium/leukocyte index. Regardless of the prostheses type used, no significant change in the parameters was identified among patients with a healthy periodontium, before and after prosthetic treatment. In all study groups, a statistically increase (p value < 0.05) was observed in the oral epithelial cell counts and a statistically decrease (p < 0.05) in the PMNs count following the use of the fixed prostheses. Data on cytomorphometric analysis could enable the selection of the most appropriate prostheses for use in patients with periodontal pathologies. When choosing prostheses, changes in the composition of GCF could be considered as a useful criterion for their use.