Influence of thermal aging on the marginal integrity of computer aided design/computer aided manufacturing fabricated crowns.

Background/purpose: The adaptation and marginal integrity of computer-aided designed and computer-aided manufactured (CAD/CAM) crowns after exposure to thermal aging need to be investigated. The present in-vitro study was designed to investigate the marginal integrity of CAD/CAM fabricated crowns cemented on extracted teeth after thermocycling aging. Materials and methods: Twenty-six newly extracted human premolars were prepared for full-coverage CAD/CAM crowns and were divided into two groups (leucite-reinforced glass-ceramics and lithium disilicate glass-ceramics). Both crowns' groups were cemented using dual curing resin cement. All specimen margins were measured for marginal integrity using an imaging system 24 h post cementation; then after 1, 3, and 5 estimated clinical years (10,000, 30,000, and 50,000 thermocycles). Two-way ANOVA analysis were used to determine whether the mean value difference is significantly different (ɑ = 0.05). Results: The average margin gaps recorded for leucite-reinforced glass-ceramic crowns were: 82.61 µm initial, and 91.02 µm after 5 estimated clinical year). For the lithium disilicate glass-ceramic crowns, the average margin gaps recorded were: 100.01 µm initial, and 120.21 µm after 5 estimated clinical year. During all measuring intervals, the leucite-reinforced glass-ceramic crown group had a lower marginal discrepancy. No statistically significant difference between the two groups was recorded. Conclusion: After being subjected to thermocycling, both CAD/CAM ceramic crowns, exhibited an increase in their marginal discrepancy; the difference was within the accepted clinical range.

Resin infiltration for white spot lesions: An in vitro experimental trial.

OBJECTIVE: To evaluate the aesthetic outcome by varying the duration allowed for infiltrant penetration when treating white spot lesions with resin infiltration. DESIGN: An in vitro, experimental randomised study. METHODS: Artificially created white spot lesions (WSLs) were induced on 100 extracted anterior teeth (T1). Teeth were divided into enamel and dentine groups depending on the extent of the lesion and then randomly assigned into different treatment protocol groups: penetration times of 3, 6 and 9 min. Resin infiltration treatment was applied according to the treatment protocol assigned (T2). Samples were thermocycled for 10,000 cycles (1 clinical year) (T3). The samples from the 3-min enamel and dentine groups were then randomly assigned into either a repeat treatment or no additional treatment group (T4). Samples were then thermocycled for an additional 10,000 cycles (T5). Spectrophotometric analysis was measured colour change (ΔE) for all groups. RESULTS: Mean ΔE values equal to or greater than the critical value (3.7) indicate a detectable clinical difference in colour of the treated WSL when compared to before WSL formation. Mean ΔE values, for the enamel groups, were slightly above or significantly below the critical value, and for the dentine groups, were significantly above the critical value. Mean ΔE values within the enamel and dentine groups both demonstrated a downward trend with increasing time allowed for resin infiltrant penetration (P < 0.05). No significant mean ΔE difference (P = 0.53) was found between groups that received a single or repeat treatment. After the first thermocycling event, no significant difference in colour change was observed in all groups except for the deep dentine lesion treated for 3 min. There was a significant difference in colour change for all groups except the enamel group that received a single treatment following thermocycling after a single or repeat treatment. CONCLUSION: Increasing the resin infiltrant penetration time to at least 9 min is advised as the most optimised treatment protocol. Resin infiltration treatment should be done only once to treat a particular white spot lesion as subsequent treatment for the same lesion results in marginal colour improvement. The colour improvement of WSLs resulting from the resin infiltration treatment can be expected to last for at least 1 year. Resin infiltration treatment of shallow lesions with a single and optimised infiltration technique can be expected to last an additional year.

The Dental Educational Environment of Online and Blended Learning during COVID-19, and the Impact on the Future of Dental Education.

Blending face-to-face and online learning should create a focused environment that supports deep and meaningful teaching and learning that engages learners in a more active and collaborative educational experience. The present study aimed to evaluate students' online and blended learning educational environment self-perception at the Faculty of Dentistry, Kuwait University, during the COVID-19 pandemic. METHODS: Undergraduate dental students who participated in blended learning with online lectures were invited to participate. The sample was a non-probability convenient sample, which included all clinical dental students invited to participate, who were enrolled in the fifth, sixth, and seventh (clinical year) years. All 69 students in these three clinical years were invited to participate. Electronic consent to participate and a self-administered questionnaire of two parts were completed. Part one of the questionnaire utilized the five subscales of the Dundee Ready Educational Environment Measure (DREEM) questionnaire; part two was developed in addition to evaluate the online teaching and learning subscales. RESULTS: Descriptive statistics and analyses of variance were performed; Pearson correlations were made between the additional supplemental online teaching subscale and the original DREEM subscales. The mean students' perception of the teacher was high, followed by the academic self-perception and then the learning perception. Students' social self-perceptions had the lowest reported scores. Students' perceptions varied by year of education in all subscales except for the online domain. In comparing all domains (DREEM and the online component), graduating students (final year) had a more favorable perception than other students. CONCLUSIONS: Within the limitations of the present study, online and blended learning were positively perceived, excluding the social self-perception and the perception that the online teaching time was not well used.

The Associations of Cardiometabolic and Dietary Variables with Clinical Periodontitis in Adults with and without Type 2 Diabetes: A Cross-Sectional Study.

Periodontitis is a commonly occurring inflammatory oral disease affecting a large proportion of global and US adults and is characterized by the destruction of the tooth-supporting apparatus. Its etiology is multifactorial, and type 2 diabetes and diet play critical roles in its remission and progression. However, few studies have addressed nutritional and serum vitamin D status in adults with periodontitis in the presence of diabetes. A cross-sectional study (n = 78), and a sub-set of age- and BMI-matched case-control studies (n = 50), were conducted to examine differences in dietary and cardiometabolic variables, and serum vitamin D in adults with periodontitis with or without diabetes. Participants provided fasting blood samples and 24-h diet recalls on at least two different days. Data on health history, body weight, height, nutritional habits, and clinical features of periodontitis were also collected. The Mann-Whitney U Test (with exact p-value estimation by Monte Carlo simulation) was used to examine differences by diabetes status in continuous and ordinal variables. Results revealed significantly lower serum vitamin D, and dietary intake of fruits, vegetables, dairy, vitamins A and C in adults with periodontitis with vs. without diabetes in the sub-study (all p < 0.05). In the overall sample, adults with diabetes presented with higher caries risk measures and lower numbers of teeth than those without diabetes; plaque and bleeding scores did not differ by diabetes status. Finally, a significant associations of food habits was observed, especially consuming protein-rich foods twice a day with a lower bleeding score, and daily consumption of fried or fast foods with a fewer number of teeth present (all p < 0.05). The present findings show significant dietary and serum vitamin D inadequacies among adults with periodontitis, and diabetes further aggravates the observed malnourishment and oral health.

Molar Incisor Hypomineralization: Awareness among Postdoctoral Dental Residents: A Cross-Sectional Study.

BACKGROUND: Molar incisor hypomineralization (MIH) is the presentation of an enamel defect, where incisors and one (or more) molars are affected. Identifying MIH is significant in restoring its visual defect and avoiding pain or other consequences of this condition. The present cross-sectional study aimed to evaluate the awareness, ability, and confidence in identifying MIH among postgraduate residents in the state of Nevada. METHODS: This cross-sectional study was conducted among postdoctoral dental residents at the School of Dental Medicine, University of Nevada, Las Vegas. This cross-sectional study used images of cases of MIH and a survey to collect the data. The survey included demographics, educational background, and basic knowledge of MIH. RESULTS: The response rate to the invitation to participate was 91%. The confidence in identifying MIH was 100%, 50%, and 33.3% for pediatric, orthodontic, and general practice residency (GPR). A total of 70% were aware of this anomaly from their predoctoral dental education and indicated the need for further related education. There was 33% confusion with fluorosis and 16.6% with amelogenesis imperfecta. A total of 66.6% of the participants indicated that they require further education relating to MIH. CONCLUSION: Within the limitations of the present investigation, MIH awareness among the investigated groups varied but was highest amongst the pediatric residents.

A Retrospective Evaluation of the Prevalence of Cracked Teeth Among an Adult Population in Nevada.

OBJECTIVE: To identify the distribution and characteristics of cracked teeth in a Southern Nevada population attending the dental clinics of the School of Dental Medicine, University of Nevada, Las Vegas (SDM, UNLV). METHODS: A retrospective keyword search of the clinical notes of SDM, UNLV patient charts in AxiUm™ was performed using the search terms 'crack' and 'fracture' to discern the number of patients that had clinically identifiable teeth with cracks, and which teeth (if any) had documented symptoms consistent with the cracks. The inclusion criteria for the record search were individuals ≥18 years old, seen at the dental clinic between 2010 and 2018. Demographic data were analyzed using a Chi-square test against the demographics for Clark County's population. RESULTS: 893 patients presented with cracked teeth, of which 41% had documented symptoms. Patients in the 45-54 age range had the highest number of teeth with cracks (P<0.001). Males comprised 49% of the cases. Caucasians (58.9%) and African Americans (21.1%) represented a majority of the population with cracked teeth (P<0.0001). 1st and 2nd molars had the highest predilection for fractures (59.8%). CONCLUSION: Mandibular and maxillary first and second molars were amongst the highest teeth affected with cracks.

Prevalence of hyperdontia, hypodontia, and concomitant hypo-hyperdontia.

BACKGROUND/PURPOSE: Anomalies in human dentition are some of the most common occurrences of congenital abnormalities. Present study aimed to determine the prevalence of hypodontia, hyperdontia and concomitant hypo-hyperdontia (CHH) among patients attending the University of Nevada, Las Vegas (UNLV) School of Dental Medicine clinics. MATERIALS AND METHODS: Retrospective search was conducted on patients' clinical notes in AxiUm™. Search included using keywords such as "hypodontia", "hyperdontia", "supernumerary teeth" and "congenitally missing". Panoramic radiographs were used to confirm the hyperdontia, hypodontia or CHH for patients attending the UNLV SDM clinics from 2010 to 2018. Collected data were analyzed using the chi-square test. RESULTS: 1101 patients were populated using the keywords. From these populated patients, 186 had hyperdontia, 23 hypodontia, and 3 presented with CHH. The distribution of males and females was 54.7% and 45.3% respectively. Hispanics, African Americans, Asians, Caucasians and ethnically unspecified patients represented 43.39%, 14.25%, 3.30%, 8.02%, and 31.13%, respectively, of those patients with a dental anomaly. Hyperdontia was most common amongst Hispanic patients with 39.24%, followed by the unspecified patients at 32.8% as well as amongst males at 56.45% (P value of 0.03). Unidentifiable supplemental teeth were overall the greatest in number with the lower right premolars, tooth 44, being the most common. This was demonstrated in the Hispanic patients whereas within the African American patients a 4th molar was in excess. CONCLUSION: Hispanic patient population has a significant link to dental anomalies, specifically hyperdontia while the presence of the fourth molar was prominent among African American patients.

The impact of impression coping geometrical design on accuracy of implant impressions: an experimental study.

AIM: This in vitro study aimed to evaluate the effect of implant impression coping geometrical designs on the accuracy of open and closed impression techniques and in the parallel and nonparallel implant positions. MATERIAL AND METHODS: Three custom-made acrylic resin models of three tested implant systems (Straumann®, SIC Invent®, and Osstem®) with diverse coping geometrical designs were evaluated in simulated cases of two parallel and two nonparallel implants. The horizontal and vertical discrepancies were measured and analyzed. RESULTS: No statistically significant differences between the two impression techniques in either parallel or nonparallel implants were observed. The high retentive design of the Osstem system showed a statistically significant difference. CONCLUSION: The geometrical design of the impression copings did not affect the accuracy for either the open and closed tray techniques. However, the high retentive coping design of the Osstem implant affected the accuracy in the open tray technique.

Retrospective Analysis of the Risk Factors of Peri-implantitis.

AIM AND OBJECTIVE: Peri-implantitis is a key concern for dental implants and the main common reason for implant failure. This investigation evaluated the risk factors and their implications on peri-implantitis. MATERIALS AND METHODS: A retrospective search of the patients' clinical notes was performed to identify the documented cases of peri-implantitis. The inclusion criteria encompassed patients who were 18 years and older and were seen at the School of Dental Medicine, University of Nevada, Las Vegas, from January 2014 through September 2018. The search revealed that the number of peri-implantitis cases was 28, with an overall 45 implants. Data were collected and analyzed using the Chi-square test. RESULTS: Total 28 patients presented with peri-implantitis. The distribution of males to females with peri-implantitis was 60.7 and 39.3%, respectively. The highest number of patients (21.4%) presenting with peri-implantitis fell within the age range of 65-69 years; 53.3% of peri-implantitis cases were in the maxillary arch. The predilection area for peri-implantitis was the mandibular first molar (24.4%). Periodontitis was the most significant cause (60.7%); respiratory diseases (42.9%) followed by hypertension (28.6%) were the most prevalent medical conditions in the studied population. Peri-implantitis occurred most frequently among Caucasians (62.7%), followed by Hispanics (29%). CONCLUSION: Within the limitations of the current evaluation, findings support previous claims that periodontitis remains the strongest predictor of peri-implantitis. A correlation may exist between peri-implantitis and the location of the implant and respiratory disease. CLINICAL SIGNIFICANCE: The implant location, the presence of periodontitis, and respiratory diseases are considered to be risk factors for peri-implantitis.

A prospective clinical study on implant impression accuracy.

BACKGROUND: An accurate impression is crucial to the long-term success of dental implants. This investigation evaluated the accuracy of the open and closed implant impression techniques in partially edentulous patients who received two adjacent implants. MATERIAL AND METHODS: Forty patients received Osstem Implants (Osstem Implant System, Seoul, Korea). Two impressions were made for each patient, one using an open tray and a second with a closed tray technique. The horizontal distances between two impression copings were measured and compared to similar measurements on the master casts. Also, under a stereomicroscope (AmScop14370, Myford Road, #150, Irvine, CA 92606 USA) at a 50-fold magnification, the presence or absence of the marginal discrepancies was evaluated. RESULTS: There were no statistically significant differences regarding horizontal measurements and in the marginal relationship for the two impression techniques, except between the anterior and posterior regions, for the closed tray technique. There were also no statistically significant differences in the impression accuracy between maxillary and the mandibular arches. In addition, there were no statistically significant differences for the intraoral horizontal distances, compared to similar horizontal measurements on master casts, between the open and closed tray techniques. CONCLUSIONS: Within the limitations of the present study, there were generally no differences in the impression accuracy between the open and closed tray techniques in partially edentulous patients with two adjacent implants.

Patient-dentist relationship and dental anxiety among young Sudanese adult patients.

OBJECTIVE: To evaluate the effects of the patient-dentist relationship on dental anxiety among young adult Sudanese patients. MATERIALS AND METHODS: In this cross-sectional study, 864 patients attending outpatient dental clinics of the governmental dental hospitals in Khartoum, Sudan were recruited; 51.2% were males and 48.8% were females, with an age range of 18-24 years. The questionnaire used evaluated the socio-demographics, education levels, economic status, patient experience, and also included the Dental Anxiety Scale, Corah (J Dent Res 1969 48: 596). RESULTS: High dental anxiety was reported by 22.2%, 29.5% reported moderate dental anxiety, and 48.3% reported low or no dental anxiety. There were statistically significant associations between dental anxiety and gender, time lapse since the previous dental visit (P < 0.004) and the reason for the previous visit (P < 0.001). In addition, the dental clinic environment (P < 0.002), the time waiting before seeing the dentist (P < 0.001) and the overhearing of pain expressed by other patients (P < 0.001) were also statistically significant. Negative comments by the treating dentist also had a statistically significant impact (P < 0.032). In contrast, a clear explanation of related dental care (P < 0.008), as well as the allowance of adequate time to discuss oral health (P < 0.006), had significantly positive effects. CONCLUSION: The study showed that the patient-dentist relationship had a significant association with dental anxiety, and may be an important target for improving the delivery and standards of oral health in dentally anxious patients in this region.

Patients' satisfaction and maintenance of fixed partial denture.

OBJECTIVES: The aims of this study were to evaluate patient satisfaction with fixed prosthesis following placement and to assess the oral health and oral hygiene practices awareness by survey questionnaire. MATERIALS AND METHODS: One hundred and ninety-two questionnaires were filled by patients wearing fixed prosthesis; the questionnaire included the subjective perception of treatment with fixed prosthesis, patients' perception of clinical outcome, regarding esthetics, masticatory function, speech, and together patient's attitude toward oral hygiene measures. RESULTS: Results showed that 84% of the patients were satisfied with their fixed prosthesis, while only 46.4% of patients were satisfied with the chewing ability. In concern, with esthetic outcome, 80% of patients showed that they were satisfied with the esthetic. The results showed that a high significantly number of patients did not use any form of interdental aids' to clean their fixed prosthesis (94%). The main reason for not using any dental aids' (91.1%) was a lack of post fixed prosthodontics instructions and not been informed by the dentist. CONCLUSION: High percentages of patients were satisfied with their fixed prosthesis. The most important finding of this study was that majority of patients showed a lack of knowledge regarding post fixed prosthodontics instructions and the significance of maintenance of fixed prosthesis using dental aids'. Of particular concern was the majority of dentists did not pay attention to the post treatment instructions concerning the maintenance of fixed prosthesis.

Identifying the tooth shade in group of patients using Vita Easyshade.

OBJECTIVE: The aim of the present investigation is to identify tooth shade among a group of Sudanese patients. MATERIALS AND METHODS: Total number of patients was 227. Participant's age ranged from 15 to 72 years, which, was divided into four groups. The tooth included in the study was either right or left sounds maxillary central incisor. Vita Easyshade was used to select the tooth shade. Investigation of the differences of Commission International de l'Eclairage (CIELab) coordinates among gender and state of origin was conducted together with an examination of the relationship between CIELab coordinates and age. One-way analysis of variance was used to test the differences in L*, a* and b* according to state of origin. RESULTS: Results showed that A3 was the most common classical tooth shade respectively. There was highly significant difference in L* between males and females (P = 0.002). There was a significant relation between tooth shade and age (P = 0.026). There was a high significant association between classical tooth shade and Sudan regions (P = 0.00). CONCLUSION: In conclusion, most common classical shade was A3, women's teeth were lighter than men's. There was a relation between ethnic background and tooth shade.

Coronal microleakage for readymade and hand mixed temporary filling materials.

INTRODUCTION: The purpose of this in vitro study was to evaluate the sealing ability of the readymade temporary filling and hand mixed materials by assessing coronal microleakage. MATERIALS AND METHODS: Standardized access cavities were prepared in 80 intact human permanent premolar teeth. They were divided randomly into four experimental groups (n=20). The teeth were restored using one of the temporary materials including Cavisol, Litrak, Zinc phosphate cement, Zinconol (IRM). Thermocycling was applied on the specimens. Methylene blue dye was applied and penetration was evaluated under stereomicroscope. Grading of the microleakage pattern was from 1 to 3, with 3 providing the best seal. Results were analyzed using one-way ANOVA test (P<0.05). RESULTS: Microleakage of Cavisol and Litrak samples achieved grade 3; whereas zinc phosphate cement and Zinconol samples absorbed the dye into the bulk of the materials. Cavisol was found to exhibit the best seal amongst the four tested materials followed by Litrak, zinc phosphate cement, and Zinconol. There was a statistically significant difference in the microleakage scores obtained between the materials (P<0.01). CONCLUSION: Among the four materials tested, readymade temporary filling provided the best sealing ability over hand-mixed. This study emphasizes the importance of correct placement and sufficient thickness of temporary filling materials in endodontic access cavities to ensure a tight seal.