A review of mechanism of action of outdoor exposure in preventing myopia incidence and progression.

Various studies have suggested several environmental, pharmacological, medical, and optical interventions and some are in use but their efficacy in myopia control may be transient, and the cellular, molecular, and biochemical mechanisms involved unclear. Daylight exposure is currently regarded as an effective and enduring strategy in the control of myopia development and progression. However, the mechanism behind the effect of outdoor exposure and its association with genetic predisposition and other relatively more significant environmental factors on myopia is still a conundrum. This review focuses on survey-based and intervention-based studies carried out to propose a mechanism that accounts for myopia development and important for its control.

Development of Artificial Intelligence Models for Tooth Numbering and Detection: A Systematic Review.

Dental radiography is widely used in dental practices and offers a valuable resource for the development of AI technology. Consequently, many researchers have been drawn to explore its application in different areas. The current systematic review was undertaken to critically appraise developments and performance of artificial intelligence (AI) models designed for tooth numbering and detection using dento-maxillofacial radiographic images. In order to maintain the integrity of their methodology, the authors of this systematic review followed the diagnostic test accuracy criteria outlined in PRISMA-DTA. Electronic search was done by navigating through various databases such as PubMed, Scopus, Embase, Cochrane, Web of Science, Google Scholar, and the Saudi Digital Library for the articles published from 2018 to 2023. Sixteen articles that met the inclusion exclusion criteria were subjected to risk of bias assessment using QUADAS-2 and certainty of evidence was assessed using GRADE approach.AI technology has been mainly applied for automated tooth detection and numbering, to detect teeth in CBCT images, to identify dental treatment patterns and approaches. The AI models utilised in the studies included exhibited a highest precision of 99.4% for tooth detection and 98% for tooth numbering. The use of AI as a supplementary diagnostic tool in the field of dental radiology holds great potential.

Remineralizing pretreatment using casein phosphopeptide-amorphous calcium phosphate fluoride, self-assembling peptide, and nanohydroxyapatite gel activation via invisible infrared light on the dentin microhardness and micro shear bond strength to the composite restoration.

AIM: Different remineralizing pretreatments Casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), tricalcium phosphate fluoride (TCP-F), self-assembling peptide (SAP) P11-4 and 10 % Nanohydroxyapatite (nHA) gel activation via invisible infrared light on the dentin microhardness (MH) and micro shear bond strength (µSBS) of composite restoration. METHODS: Seventy-five human molar teeth were collected and the dentinal surface of all the samples was exposed to different demineralizing solutions. (n = 15) Group 1 (demineralized dentin), Group 2 (CPP ACP), Group 3 (TCP-F), Group 4 (SAP P11-4), Group 5 (nHA gel activation via invisible infrared light). MH assessment was performed using Vickers hardness. Each group of 10 samples was subjected to composite restoration buildup and µSBS were tested. The debonded samples were then observed under a stereo-microscope for failure analysis. ANOVA was conducted, along with Tukey's post hoc analysis, to examine the µSBS of composite and MH of the remineralized surface. RESULTS: nHA gel activation via invisible infrared light pretreated specimens showed the maximum outcomes of surface hardness (331.2 ± 77.3) and bond strength (10.38 ± 2.77). However, Group 4 (SAP P11-4) (148.3 ± 29.2) remineralized dentin displayed minimum scores of MH and µSBS (5.88 ± 1.01). CONCLUSION: Remineralizing pretreatment nHA gel activation via invisible infrared light and casein phosphopeptide-amorphous calcium phosphate fluoride seem to improve the dentin MH and µSBS of the composite restoration.

Prevalence, Pattern, Mortality, and Morbidity of Traumatic Small Bowel Perforation at King Abdulaziz Medical City: A Retrospective Cohort Study.

Introduction Bowel perforation, whether from trauma or other causes, presents with diverse clinical scenarios. Small bowel perforation (SBP), a potentially fatal condition often linked to blunt trauma like motor vehicle accidents, necessitates prompt detection and intervention, crucial for improved outcomes. This study investigated the prevalence, predictors, presentation, diagnostic findings, morbidity, and mortality of traumatic SBP for comprehensive insights. Methodology This was a retrospective cohort study conducted at King Abdulaziz Medical City, Riyadh. A review of 838 cases, which represent all abdominal trauma patients from January 2017 to March 2023, was done. Forty patients who developed SBP and have complete data were included in this study. One case was excluded due to incomplete medical records. Data were collected with the non-probability convenience sampling technique via the BestCare system using a data collection sheet. Data were analyzed with IBM SPSS 29 (IBM Corp., Armonk, NY). Results Out of all abdominal trauma cases (n=838), 40 patients developed SBP (n=40, 4.77%). Males constituted 87.5%, and the most common mechanism was motor vehicle accidents (57.5%). Complications included cardiac arrest, disseminated intravascular coagulation (DIC), and leak (7.5% each). In motor vehicle accidents, SBP primarily affected patients who were in the driver's position (78.3%). Clinical signs at presentation revealed abdominal tenderness (52.5%), abdominal distension (22.5%), and abnormal systolic blood pressure (mean 115.3 mmHg). Linear regression showed gender and age positively associated with morbidity (p=0.474, p=0.543) while BMI exhibited a negative relationship (p=0.314). Logistic regression revealed non-significant predictors of mortality, except for mean initial hematocrit (HCT) (p=0.721, aOR=0.098). Conclusion Our study provides crucial findings on the incidence, patterns, mortality, and morbidity of traumatic bowel perforation, contributing to the existing body of research. The identified prevalence of 4.77% and mortality at 17.5% from the studied population underline the serious impact of this condition, and the 37.5% complication rate observed demonstrates the potential risks involved. The average hospital stay is found to be 14 days, adding further to the disease burden. These findings underscore the importance of specific preventative measures, particularly related to motor vehicle accidents (MVAs), and highlight potential markers for predicting outcomes, such as age, gender, and mean initial HCT. This substantiates the need for further research involving larger cohorts and prospective designs to gain comprehensive insights and establish more robust preventative and treatment strategies.

Effect of Gold Nanoparticle Radiosensitization on DNA Damage Using a Quartz Tuning Fork Sensor.

The development of sensor technology enables the creation of DNA-based biosensors for biomedical applications. Herein, a quartz tuning fork (QTF) sensing system was employed as a transducer for biomedical applications to address indirect DNA damage associated with gold nanoparticles (GNPs) and enhance the effectiveness of low-dose gamma radiation in radiation therapy. The experiment included two stages, namely during and after irradiation exposure; shift frequencies (Δf) were measured for 20 min in each stage. During the irradiation stage, the QTF response to DNA damage was investigated in a deionized aqueous solution with and without 100 nm GNPs at different concentrations (5, 10, 15, and 20 µg/mL). Upon exposure to gamma radiation for 20 min at a dose rate of 2.4 µGy/min, the ratio of Δf/ΔT indicates increased fork displacement frequencies with or without GNPs. Additionally, DNA damage associated with high and low GNP concentrations was evaluated using the change in the resonance frequency of the QTF. The results indicate that GNPs at 15 and 10 µg/mL were associated with high damage-enhancement ratios, while saturation occurred at 20 µg/mL. At 15 µg/mL, significant radiotherapy enhancement occurred compared to that at 10 µg/mL at 10 min after exposure. In the post-irradiation stage, the frequency considerably differed between 15 and 10 µg/mL. Finally, these results significantly depart from the experimental predictions in the post-radiation stage. They exhibited no appreciable direct effect on DNA repair owing to the absence of an environment that promotes DNA repair following irradiation. However, these findings demonstrate the potential of enhancing damage by combining GNP-mediated radiation sensitization and biosensor technology. Thus, QTF is recommended as a reliable measure of DNA damage to investigate the dose enhancement effect at various GNP concentrations.

Clinical, Radiographic Peri-Implant Parameters and Patient Satisfaction with Splinted and Non-splinted Short Dental Implants in the Maxillary Premolar-Molar Region: A Long-Term Retrospective Clinical Study.

PURPOSE: The goal of this study was to assess the peri-implant condition, peri-implant bone loss (PBL), and complication rates of short dental implant-supported splinted crowns (SDI-SCs) and non-splinted crowns (SDI-NSCs) in the maxillary premolar-molar region. MATERIALS AND METHODS: Patients who had short implants placed near their maxillary sinuses were evaluated. Both patient satisfaction and presence of any technical complication, e.g. porcelain wear and chipping, loss of retention and loosening of the abutment, fixture or screw, were noted. The peri-implant plaque index (PIPI), probing depth (PIPD), bleeding on probing (PIBP), and peri-implant bone loss (PBL) were evaluated. To assess the impact of prosthesis type and SDI placement on technical problems, a log-rank test was computed. p < 0.05 was considered statistically significant. RESULTS: A total of 72 patients agreed to be followed-up, showing a mean follow-up time of 3.1 years. Ninty-five implants in total (55 SDI-SCs, and 40 SDI-NSCs) with moderately rough surfaces were evaluated. The average PBL score for implant and patients was 1.27 (0.02-3.97) and 1.25 (0.03-4.41), respectively. More technical complications were observed with single crowns than with splinted crowns. There were no statistically significant differences in the peri-implant parameters between SDI-SCs and SDI-NSCs (p > 0.05). PBL at molar sites was substantially higher than at premolar sites (p = 0.048). Sixty patients (83.3%) were satisfied with the appearance of the crowns, while 57 patients (79.1%) were satisfied with the crowns' performance. CONCLUSION: The peri-implant conditions, bone levels, technical complication rates and patient satisfaction were comparable between the SDI-SCs and SDI-NSCs. However, implants placed in the molar sites had statistically significantly greater bone loss in comparison to those at the premolar sites.

The Lifetime Expenditure in People with Keratoconus in Saudi Arabia.

AIM: This study measured and evaluated the socioeconomic burden of people living with keratoconus in Saudi Arabia. METHODS: This study employed a cross-sectional design, a Keratoconus Economic Burden Questionnaire, and a convenient sample of 89 keratoconus patients (58.4% male) drawn from multiple regions in Saudi Arabia. It was conducted using online surveys, and the data were analyzed using appropriate quantitative techniques. RESULTS: The mean age and annual income of the participants were 33.24 (SD = 6.82) years and USD 9046.52 (SD = 16,866.48), respectively, with only 37% being employed for wages. Up to 94.4% needed glasses or contact lenses at least once a week, and 73.0% received care from optometrists. The condition forced 45.9% of the respondents to change careers or leisure activities, with a further 51.3% having to take time off work. The mean annual out-of-pocket expenses for buying and maintaining glasses or contact lenses, as well as traveling and accommodation for keratoconus-related treatment were USD 2341.76 (SD = 3053.09), with 48.32 incurring upwards of USD 3240 over the period. The treatment costs increased with disease duration, r(89) = 0.216, p < 0.05. Regression results showed that the existence of comorbid eye disease, changing glasses at least once a year, and wearing either glasses or contact lenses at least once a week individually had statistically significant negative effects on the total annual keratoconus treatment costs, while disease duration, utilization of optometrists, and taking time off had a statistically significant increase on the total cost (p < 0.05). CONCLUSION: With a prevalence rate of 1 in 375, progressive debilitation, and the lifetime nature of the disease, keratoconus is a critical public health concern in Saudi Arabia. The resulting visual impairment and discomfort, as well as both direct and indirect economic burdens, have considerable impacts on the patient's quality of life.

Corneal Densitometry to Assess the Corneal Cystine Deposits in Patients With Cystinosis.

PURPOSE: The purpose of this study was to assess the suitability of corneal densitometry measurements obtained with Scheimpflug imaging in estimating the corneal changes caused by cystine deposits in the cornea in patients with cystinosis. METHODS: Scheimpflug imaging (Pentacam) was performed for 14 patients with cystinosis and 16 age-matched controls. Pentacam data were used for analysis of the corneal densitometry at different zones in the cornea for patients with cystinosis and controls. Densitometry measurements were compared with the corneal crystal scores obtained from the slitlamp images for patients with cystinosis. RESULTS: There was no statistically significant difference in keratometry measurements between the 2 groups ( P > 0.05). Corneal thickness was found to be significantly higher in the control group when compared with the cystinosis group ( P = 0.0004). The mean corneal densitometry was significantly higher in patients with cystinosis when compared with controls at most of the corneal layers and zones. The corneal densitometry readings for the right and left eyes showed moderate positive correlation with the corneal crystal score with a ceiling effect being reached at the maximum corneal crystal score of 3. CONCLUSIONS: Corneal densitometry obtained through Pentacam can be used as an objective estimate of the level of cystine crystals present in patients with cystinosis. The clinical estimate of corneal crystal score, although effective at low levels of crystal deposition, does not allow for accurate estimates of change when the level of crystal deposition is high leading to limited utility when assessing treatment effects. Hence, densitometry measurements can potentially be used to assess treatment efficacy of cystinosis treatments in clinical settings.

Anatomical Distribution Patterns of Peripheral Arterial Disease in the Upper Extremities According to Patient Characteristics: A Retrospective Cohort Study.

Purpose: Peripheral arterial disease (PAD) greatly affects the patients' quality of life. We aimed to investigate the affected anatomical sites and distribution patterns in upper extremity PAD using computed tomography angiography (CTA). Furthermore, we sought to identify the correlations between patient characteristics and the identified patterns. Patients and Methods: This was a retrospective chart review of upper limb CTA findings from patients with symptomatic PAD aged >18 years. Significant variables from univariate logistic regression analysis were further tested using multivariate logistic regression analysis. Statistical significance was set at p < 0.05, with confidence intervals of 95%. Results: The mean age of the 102 included patients with upper extremity PAD was 55.45 years. Laterality analysis revealed that the upper left limb segments were more affected than the upper right limb segments (42 vs 63; left-to-right ratio, 3:2). The forearm was the segment most affected by stenotic PAD (62 segments, 3.37%). The arm was the segment most affected by occlusive PAD (14 segments, 0.76%). Diabetes mellitus (DM) and hypertension (HTN) were significant predictors of PAD (p = 0.046). In patients with DM, the occlusive form of PAD was dominant in the arm (18.18%); however, the stenotic form prevailed in the forearm (72.72%). In patients with HTN, the occlusive form of PAD was predominant in the arm (45.45%); however, the stenotic form tended to occur in the arm and forearm (90.90%). Conclusion: The distribution patterns of upper extremity PAD are linked to its underlying pathophysiology. HTN and DM are the most frequent comorbidities in patients with upper extremity PAD. Angiographically, PAD in these patients is likely to present as stenosis rather than as occlusion. This is vital for interventionists who deviate from radial arterial access in patients with PAD. Therefore, targeted screening standards are required, and further studies on PAD are warranted.

Self-Reported Student Awareness and Prevalence of Computer Vision Syndrome During COVID-19 Pandemic at Al-Baha University.

Background: The rapid increase increased, in using of video display terminals during the COVID-19 pandemic predisposes users to a variety of health problems restricted to visual problems and including various musculoskeletal problems, collectively known as computer vision syndrome (CVS) or computer vision syndrome. Aim: This study aims to ascertain university students' awareness of computer vision syndrome at Al-Baha University, including the nature, sources, accuracy, and completeness of information, as well as the attitudes towards CVS, and mitigative practices. Methods: This study used a descriptive cross-sectional design and a convenient sample of 310 (80.0% male) students drawn from Al Baha University campuses. Data were collected using self-administered questionnaires. Results: The mean age of the participants was 23.51 years (SD=5.42). The results show that 78.7%, 66.1%, and 11.6% received CVS information from social media, mass media, and family, respectfully. Despite 70% of respondents being aware of CVS manifestations, between 42% to 67% of those sampled had accurate and complete information about the meaning, causes, prevention, and management of the syndrome. More than a third of the participants had either a good (62.9%) or average (29%) total knowledge of CVS. Less than 15% had incorrect information. On average, 62.5% of respondents engaged in preventive or mitigative behaviours/activities as opposed to 37.5% who did not, but only 44% believed CVS was a serious health threat. 65.2% of the studied students had a satisfactory total practice score. The regression analysis showed that the coefficients of marital status and faculty were a statistically significant association with the total knowledge score. Conclusion: CVS awareness is acceptably high, but there is a low preventive/mitigative behaviors as well as a low realization of CVS' long-term health problems. This is why increasing CVS awareness and implementing interventions such as the 20-20-20 rule could be effective at Al Baha University.

Fracture strength of Er,Yag laser treated PMMA denture-based polymer (DBP) colonized with C. albicans, S. aureus, S.mutans, and E.coli.

AIM: To assess and equate the efficacy of different disinfection protocols autoclave, chlorhexidine (CHX), PDT utilizing Rose Bengal (RB), chitosan, and Er, Yag laser and their effect on fracture strength of PMMA denture-based polymer (DBP) colonized with C. Albicans, S. aureus, S.mutans, and E.coli. MATERIAL AND METHODS: A total of 50 (n = 10) PMMA DBP were manufactured and adulterated with the American Type Culture Collection (ATCC) of diverse microbial colonies inhabited by C. Albicans, S. aureus, S.mutans, and E.coli. The specimens were subjected to different denture disinfection approaches by randomly distributing in into five groups i.e., Er, Yag laser, RB, autoclave, CHX, and Chitosan, respectively for appraising antimicrobial effectiveness. PMMA fracture load was also assessed and statistical analysis was performed for CFU/mL (log10) of exposed C. Albicans, S. aureus, S.mutans, and E.coli by one-way ANOVA and Tukey's multiple comparison test at a significance level of p < 0.05. RESULTS: Intergroup comparison disclosed that denture disinfection with Er, Yag laser, autoclave, Chitosan, and CHX (control) validated comparable antimicrobial efficacy to denture against all inspected CFU/mL (log10) (p>0.05). The intragroup comparison revealed that DBP sanitization with Er, Yag laser, autoclave, Chitosan, RB, and CHX substantiated equivalent effective antimicrobial efficacy in plummeting CFU/mL (log10) of S. mutans and E. coli (p>0.05) but in consideration to S.aureus and C.albicans, all groups resulted in declining their count except 5µm RB activated by PDT(p < 0.05). No significant difference was perceived in fracture load of PMMA denture base among Er, Yag laser, RB, chitosan, and CHX (control) (p > 0.05) except autoclave decontamination procedure that indicated the least fracture strength of DBP when disinfected (p < 0.05). CONCLUSION: Er, Yag laser, and Chitosan activated by PDT have the potential to be used as an alternative to chlorhexidine for disinfecting Polymethyl methacrylate denture base as they demonstrated the highest antimicrobial efficacy against E. coli, C. Albicans, S aureus, and S. mutans with optimal fracture load.

10-Methacryloyloxydecyl Dihydrogen Phosphate (10-MDP)-Containing Cleaner Improves Bond Strength to Contaminated Monolithic Zirconia: An In-Vitro Study.

Contamination of zirconia restorations before cementation can impair the resin-zirconia bonding durability. The objective of this study was to evaluate the effect of human saliva or blood decontamination with 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP)-containing cleaner on the resin-zirconia shear bond strength (SBS). METHODS: A total of 220 zirconia specimens were prepared and air-abraded and randomly distributed into 11 groups (n = 20 per group). Except for the control group (no contamination), zirconia specimens were contaminated with either human saliva (five groups) or blood (five groups), and then subjected to one of five cleaning methods: water rinsing, 38% phosphoric acid etchant (Pulpdent Corp., Watertown, MA, USA), 70% isopropanol alcohol (Avalon Pharma, Riyadh, Saudi Arabia), Ivoclean (Ivoclar Vivadent, Schaan, Lichtenstein) and Katana Cleaner (Kuraray Noritake, Tokyo, Japan). The resin-zirconia SBS was tested at 24 h and after thermocycling (10 k cycles). Three-way ANOVA followed by Tukey's multiple comparisons test were utilized to analyze the SBS data. Failure modes were evaluated using a scanning electron microscope. RESULTS: Both blood and saliva significantly affected resin-zirconia SBS as contaminants. After thermocycling, there was no statistically significant difference between SBS obtained after decontamination with the Katana Cleaner (blood, 6.026 ± 2.805 MPa; saliva, 5.206 ± 2.212 MPa) or Ivoclean (blood, 7.08 ± 3.309 MPa; saliva, 6.297 ± 3.083 MPa), and the control group (no contamination, 7.479 ± 3.64 MPa). Adhesive and mixed failures were the most frequent among the tested groups. CONCLUSION: Both 10-MDP-containing cleaner (Katana Cleaner) and zirconium oxide-containing cleaner (Ivoclean) could eliminate the negative effect of saliva and blood contamination on resin-zirconia SBS.

Designing an immunoinformatic vaccine for peri-implantitis using a structural biology approach.

OBJECTIVES: Peri-implantitis is a destructive inflammatory process that affects the soft and hard tissues around dental implants. porphyromonas gingivalis, an anaerobic gram-negative bacterium, appears to be the main culprit. Since there is no efficient and specific vaccine to treat peri-implantitis, the goal of our research has been to develop a multi-epitope vaccination utilizing an immunoinformatics approach that targeted P. gingivalis type I fim A. MATERIALS AND METHODS: P. gingivalis peptides 6JKZ and 6KMF are suitable for vaccine development. B- and T-cell epitopes from 6KMF and 6JKZ were detected and evaluated based on critical factors to produce a multi-epitope vaccine construct. It was assessed based on allergenicity, antigenicity, stability. The vaccine's dual major histocompatibility complex (MHC-I and MHC-II) binding epitopes allowed it to reach a larger population. P. gingivalis fimbriae induce immune subversion through TLR -CXCR4 receptor complex pathway. The ClusPro 2.0 server was used to do the molecular docking using TLR2 - CXCR4 and vaccine epitopes as receptor and ligand respectively. RESULTS: The designed vaccine was non-allergenic and had a high antigenicity, solubility, and stability. The 3D structure of the vaccine revealed strong interaction with CXCR4(TLR2) using molecular docking. The vaccine-CXCR4 interface was more consistent, possibly because the vaccination has a higher affinity for the CXCR4-TLR2 complex. CONCLUSION: This study details the vaccine's distinct and sustained interaction with the CXCR4(TLR2) immunological receptor and its consistent and effective utterance in the bacterial system. As a result, our vaccine formulation will evoke a significant memory response and induce an adaptive immune response against P. gingivalis.

Can periodontal pockets and caries lesions act as reservoirs for coronavirus?

The periodontal pocket and likely caries lesions may act as a reservoir and source of dissemination and development of systemic infections. While periodontal pockets have been found to harbor several viral species, there is no information on its ability to serve as a reservoir for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have used a real-time polymerase chain reaction (RT-PCR) approach to evaluate SARS-CoV-2 in periodontal pockets and cavitated caries lesions in a cross-sectional study of 72 participants who were divided into six groups: symptomatic positive COVID-19 cases with periodontal pockets, symptomatic positive with cavitated caries lesions, asymptomatic positive with periodontal pockets, asymptomatic positive with cavitated caries lesions, positive control, and negative control. A total of 180 samples were interrogated by RT-PCR to amplify the SARS-CoV-2 E and S genes. SARS-CoV-2 was present in 41.7% of symptomatic positive COVID-19 cases with periodontal pockets and 16.7% of symptomatic positive with cavitated caries lesions. The mean Ct value of E and S genes in periodontal pockets patients were 36.06±0.46 and 30.06±6.73, respectively, and the mean Ct value for both genes in caries lesions patients were 35.73±4.14, and 34.78±1.93, respectively. The sensitivity, specificity, and accuracy to detect SARS-CoV-2 among periodontal pockets were 20.8% (95% CI 7.13-42.15), 100% (95% CI 73.54-100.0), and 47.2% (95% CI 30.22-64.51), respectively. Among cavitated caries lesions patients, they were 8.3% (95% CI 1.03-27.0), 100% (95% CI 73.54-100.0), and 38.9% (95% CI 23.14-56.54), respectively. SARS-CoV-2 can be detected in periodontal pockets and caries lesions, and these sites may act as reservoirs for the virus. However, the sensitivity of SARS-CoV-2 detection is low compared with other methods. To our knowledge, this report is the first to investigate the relationship between SARS-CoV-2 and periodontal pockets and caries.

Use of Photosensitizer, Glutaraldehyde, alcohol and Ultrasonics in disinfection of polished and rough surfaces of self-curing polymethyl methacrylate denture base material.

AIM: To assess the effectiveness of chemical, ultrasonic and photodynamic therapy (PDT) mediated disinfection against in-vitro biofilms colonized with C. albicans, S. oralis, and S. aureus on surfaces of PMMA (polymethylmethacrylate) denture base material. MATERIALS AND METHODS: Fifty plates of PMMA were prepared with two different surface topography (rough and polished) analyzed by profilometry. Provenance culture (ATCC) of C. albicans, S. oralis, and S. aureus were inoculated on specimens and exposed to disinfection. The disinfection included Rosebengal (RB) 5 µM activated by a red LED, 2% glutaraldehyde, 70% Isopropyl alcohol, ultrasonic disinfection, and saline solution as a control. The antimicrobial efficacy was assessed by subsequently calculating viable counts after disinfection. The data were analyzed using analysis of variance (ANOVA) and Tukey's Post Hoc test. RESULTS: The unpolished surface demonstrated the highest average surface roughness As 5.32±0.36 (µm) and root mean square roughness Rr 7.22±0.81 (µm) compared to the polished surface. Intergroup comparison demonstrated polished and rough PMMA plate disinfected with rose bengal, glutaraldehyde and alcohol-based disinfection exhibited comparable reduction against C. albicans and S. oralis CFU/mL (log10) (p>0.05). Whereas, this reduction was significantly higher on the rough and polished surface of PMMA when disinfected using ultrasounds for 30 sec (p<0.05). Rose Bengal was the most effective method of disinfection against S. aureus both on polished (0.17±0.13) and rough (0.44±0.22) denture plates (p<0.05). CONCLUSION: The ultrasonic disinfection was most effective in reducing viable microbial counts. RB mediated PDT exhibited a more substantial reduction of the colonies of S.aureus.

Study of Lateral Wall Thickness of the Maxillary Sinus in Left and Right Sides for Female and Male: A Cross Sectional Retrospective Study Using Cone Beam Computed Tomography.

BACKGROUND: Dental implants are considered the first option to replace missing teeth. Alveolar bone resorption gradually progresses following tooth extraction leading to loss of vertical bone dimension for implant placement. The lateral window approach is the most commonly used procedure to treat vertical bone loss. OBJECTIVE: The aim of the present study is to evaluate the Lateral Wall Thickness (LWT) of the maxillary sinus and determine the influence of gender and side on maxillary LWT. METHODS: This study involved a cross sectional retrospective study. Cone- beam computed tomography data were collected from 99 patients with a total of 198 maxillary sinuses that met the inclusion criteria. The patient age ranged between 18 to 35 years. On the selected sagittal section, the points of measurement are determined by a perpendicular line at 5 mm from the lowest point of the sinus floor. Measurements were taken at four different areas; first premolar (P1), second premolar (P2), first molar (M1), and second molar (M2). Descriptive statistics were used to calculate mean lateral wall thickness for each tooth, and student's t-test was used to test the effect of gender and side on maxillary LWT. RESULTS: The greatest mean LWT was observed around the left first maxillary molar (2.43±0.82), while the lowest mean LWT was observed around the right second maxillary premolar (1.62±0.61). There was no significant difference in the LWT around any tooth (M1 p=0.56, M2 p=0.92, P1 p=0.14, P2 p=0.19). CONCLUSION: There was no significant difference in both males and females of the lateral wall thickness in the left and right side of maxillary sinus.

Vertical relationships between the divergence angle of maxillary molar roots and the maxillary sinus floor: A cone-beam computed tomography (CBCT) study.

AIM: To assess the relations between the divergence angle of the maxillary molar roots and their proximity to the maxillary sinus floor using CBCT. METHOD: This study comprised CBCT scans of the maxilla, including at least the inferior one-third of the maxillary sinus and at least one molar present in any quadrant with complete eruption and root formation. Evaluation included the vertical relations between the maxillary molar root apices and the maxillary sinus floor (MSF), and the root divergence was measured from the root apices to the floor of the pulp chamber. The chi-square test was used for the associations between the study parameters. For the correlation between root divergence angles and MSF vertical relationship types, the Spearman test was used. A P-value < 0.05 was considered significant. RESULTS: A total of 100 scans were analyzed, including 316 permanent maxillary first and second molars. The MSF Type II vertical relationship was the most prevalent (39.6%), followed by Type I (31.3%). The highest divergence angle was found between the distobuccal and palatal roots (mean = 44.9 ± 10.5°). For the mesiobuccal-distobuccal angle groups, there were higher percentages of the MSF Type I and II relationships among the angle groups < 1° and 21-45°. For the mesiobuccal-palatal angle groups, a higher prevalence of the MSF Type II relationship was found in the <21° and >45° angle groups, and a higher prevalence of the Type I relationship was found in the 21-45° angle group. For the distobuccal-palatal angle groups, higher percentages of the MSF Type II relationship were found in the three angle groups. For all teeth, there was a significant positive correlation between the MSF vertical relationship and the mesiobuccal-palatal angle (r = 0.116; P = 0.039). CONCLUSION: There was a positive correlation between the divergence angle of the roots and their vertical relationship with the MSF. Clinicians should assess the divergence between the roots before performing extraction or endodontic treatments.

Evaluation of Stress Distribution during Insertion of Tapered Dental Implants in Various Osteotomy Techniques: Three-Dimensional Finite Element Study.

Conventional osteotomy techniques can, in some cases, induce higher stress on bone during implant insertion as a result of higher torque. The aim of the present study was to evaluate and compare the stress exerted on the underlying osseous tissues during the insertion of a tapered implant using different osteotomy techniques through a dynamic finite element analysis which has been widely applied to study biomedical problems through computer-aided software. In three different types of osteotomy techniques, namely conventional (B1), bone tap (B2), and countersink (B3), five models and implants designed per technique were prepared, implant insertion was simulated, and stress exerted by the implant during each was evaluated. Comparison of stress scores on the cortical and cancellous bone at different time points and time intervals from initiation of insertion to the final placement of the implant was made. There was a highly statistically significant difference between B1 and B2 (p = 0.0001) and B2 and B3 (p = 0.0001) groups. In contrast, there was no statistically significant difference in the stress scores between B1 and B3 (p = 0.3080) groups at all time points of implant placement. Overall, a highly significant difference was observed between the stresses exerted in each technique. Within the limitations of our study, bone tap significantly exerted lesser stresses on the entire bone than conventional and countersink type of osteotomy procedures. Considering the stress distribution at the crestal region, the countersink showed lower values in comparison to others.

Efficacy of porphyrin derivative, Chlorhexidine and PDT in the surface disinfection and roughness of Cobalt chromium alloy removable partial dentures.

AIM: The present study aimed to evaluate the effect of different cleansers and photodynamic therapy (PDT) on disinfection of Co/Cr removable partial denture colonized with C. albicans, S.aureus and S.mutans. MATERIAL AND METHODS: Twenty-five Co/Cr removable partial dentures were constructed. and inoculated by American Type Culture Collection (ATCC) of Candida albicans, S.aureus, and S.mutans in an in-vitro setup. Co/Cr removable partial dentures were randomly allocated into five groups and framework was immersed in 15 mL of contaminated culture medium broth. Based on the cleansing method, disinfected dentures in group 1 were cleansed with porphyrin derivative; group 2 was exposed to 0.12% chlorhexidine digluconate; samples in group 3 and group 4 were subjected to sodium perborate enzyme and citric acid respectively. Through a surface analyzer, the surface roughness of Co/Cr and methacrylate resin was measured in 3 different zones in micrometers before and after disinfection. Two-way ANOVA and Tukey's test was used to analyze the data. Levene test was used to assess the normal distribution of data. Significance level p< 0.05 RESULTS: The results of metal roughness displayed that Co/Cr used as an alloy did not exhibit significant difference when exposed to different chemical disinfectants and photosensitizer (p > 0.05). Similarly, surface roughness (Ra) of heat polymerized acrylic resin using cleansers and PDT demonstrated no significant difference. Intergroup comparison showed that, hematoporphyrin derivative displayed comparable cleansing property against S. aureus, C.albicans, and S. mutans compared to to 0.12% CHX digluconate (p>0.05). The intragroup comparison showed hematoporphyrin derivative and CHX were equally effective against all bacteria (p>0.05). CONCLUSION: CHX digluconate and hematoporphyrin derivative demonstrated high antimicrobial activity against S.aureus, S.mutans, and C.albicans with minimum Ra of an acrylic denture and Co/Cr metallic framework.

Testing the Sensitivity of Conjunctival Swabs from Confirmed COVID-19 Patients.

OBJECTIVE: To investigate the incidence of COVID-19 viral RNA in the conjunctiva of patients priorly confirmed to have COVID-19, using a conjunctival swab and to determine swab sensitivity. METHODS: This cross-sectional study enrolled patients who tested positive for COVID-19 with PCR via nasopharyngeal swabs. Conjunctival swabs were collected for each patient and subjected to RT-PCR assay. Demographic data and clinical history of patients were investigated and analysed. RESULTS: In this study, 4.9% of the patients tested positive with conjunctival swabs for COVID-19; 29.9%, 28.7%, 20.1%, and 12.2% of the patients had fever, shortness of breath, cough, and red eye, respectively. Among all patients, 18.9% and 73.2% had a history of traveling and contact with positive COVID-19 cases, respectively. There were significant correlations between the conjunctival results and diabetes (P=0.049) and hypertension (P=0.002). Traveling was a risk factor for positive conjunctival swab testing (P=0.016). The sensitivity of the conjunctival swab was 4.8%. CONCLUSION: Among all positive cases of COVID-19, a small percentage had positive results when tested using a conjunctival swab. Conjunctival swabs have very low sensitivity for the detection of COVID-19. However, tears could still be a mode of disease transmission, especially from patients to eye care specialists.