Comparison of antimicrobial efficacy of different disinfectants on the biofilm formation in dental unit water systems using dip slide and conventional methods: A pilot study.

OBJECTIVE: Biofilm formation in dental waterlines brings opportunistic infections, especially for immunosuppressive patients. This study aimed to determine biofilm-forming microorganisms by various methods and investigate disinfectants' effects on biofilm. MATERIALS & METHODS: In the study, samples were obtained from the waterlines of 10-15 aged six dental units, before (0 min.) and after chlorine dioxide (ClO2) and hypochlorous acid (HOCl) treatment (1, 5, 10, 20, and 30 min.), and total colony counts were performed using conventional surface smear method (SSM) and dip slide method (DSM). The Congo red agar and Christensen methods were used to examine the biofilm-forming properties of the isolates. Monitoring of biofilm presence was also visualized by SEM scanning. RESULTS: When DSM and SSM are compared in all units where ClO2 and HOCl are applied, DSM can detect bacterial growth even during periods of greater exposure to disinfectant application. Although DSM can achieve a value approaching 3% even at the 10th minute in units treated with HOCl; SSM does not show reproduction at the same disinfectant exposure and duration; It was observed that in the units where ClO2 was applied, the growth was no longer observed at the 10th minute with DSM, and SSM, 50% growth in the first minute of the units treated with ClO2 could not be detected in the 5th minute. CONCLUSIONS: It is concluded that it can be advisable to routinely disinfect the dental unit water systems with non-toxic doses of ClO2 application before patient treatments in clinics and also to perform contamination controls at regular intervals with DSM, which is a sensitive and very practical method. RESEARCH HIGHLIGHTS: It has been observed that the dip slide method can count bacteria more sensitively than conventional methods in dental water systems without the need for experienced personnel and equipment. The difference between biofilm formation in water systems before and after disinfectant exposure in SEM examinations is remarkable. The effects of ClO2 and HOCl on biofilm were investigated and bacterial growth was inhibited in dental units between 5 and 10 minutes with both disinfectants.

Comparison of efficacy and usability of custom mandibular advancement devices fabricated with the conventional method and digital workflow: A pilot clinical study.

PURPOSE: To compare the effects of fabricating methods of custom monoblock mandibular advancement devices (MADs) on usability and efficacy in patients with mild and moderate obstructive sleep apnea (OSA). MATERIALS AND METHODS: Digitally fabricated custom MADs (dMADs) were produced for 11 OSA participants who had previously used conventionally fabricated custom MADs (cMADs). The participants answered a modified usability questionnaire for both MADs, and the average scores that were given to the questionnaire were evaluated by age, sex, and body mass index (BMI), and the scores of cMADs and dMADs were compared. After 6 months of usage of each MAD, the apnea-hypopnea index (AHI), mean and lowest oxygen saturations, and total sleep time were measured for efficacy assessment. Data were analyzed with Cronbach's alpha, Mann-Whitney U, Kruskal-Wallis, Wilcoxon signed-rank, one-way repeated measures analyses of variance, and Bonferroni tests (α = 0.05). RESULTS: Cronbach's alpha was found at 0.834 and 0.722 for the conventional and digital questionnaires, respectively. The usability scores of the dMADs were significantly higher than those of cMADs (p = 0.013). There was no difference in usability scores in terms of sex or BMI (p > 0.05). No statistically significant difference was found for cMAD (p = 0.113) among age groups; however, there was a significant difference for dMAD (p = 0.046). The AHI, mean, and lowest oxygen saturation values were significantly affected by MAD usage (p < 0.001). However, total sleep time values did not differ after the MAD treatments (p > 0.05). Significantly lower AHI and significantly higher lowest oxygen saturation values were observed with dMAD, while both appliances led to similar results for mean oxygen saturation and total sleep time values (p > 0.05). CONCLUSIONS: Participant usability scores were higher for digitally manufactured MADs than conventionally manufactured MADs. However, both conventional and digital MADs were found effective in decreasing the AHI levels and increasing the mean and lowest oxygen saturation values of the participants.

Fabricating a custom monoblock mandibular advancement device by using an open-source nondental CAD software program and additive manufacturing: A dental technique.

Custom mandibular advancement devices (MADs) can be fabricated by using either conventional processes or computer-aided design and computer-aided manufacturing (CAD-CAM). The CAD-CAM technique involves digitizing the dental arches of the patients, designing by using a dental CAD software program, and additive manufacturing with a suitable material. This article describes the steps of the design of a custom MAD by using an open-source nondental CAD software program and of the fabrication with additive manufacturing.

Design and fabrication of an interim fixed restoration with an open-source nondental CAD software program and additive manufacturing: A technical report.

This technique aimed to identify the potential of an open-source software program and to present the design and fabrication procedures of a single interim crown with a nondental CAD software program. The steps included defining the margins, establishing the cement interval value, completing the virtual modeling of the crown, and checking the proximal and occlusal contacts by using color mapping.

Prevalence and predictors of bruxism in two university clinic patient populations with dental implants: A cross-sectional analysis.

OBJECTIVE: To analyze the prevalence, predictors, and prosthetic complications of bruxing patients with dental implants in two tertiary clinics in Istanbul, Turkey. METHODS: Patients with at least one dental implant and with a fixed prosthesis were examined for the evidence of probable bruxism. Factors that could be related to bruxism were analyzed in relation to patient-specific variables. Technical and mechanical complications were investigated. RESULTS: A total of 1688 patients were analyzed. The overall rate of probable bruxism was 19.72%. Besides self-reported bruxism (p < 0.022), antidepressant use (p < 0.002), frequent headaches (p < 0.014), and observation of linea alba (p < 0.028) were the predictors for probable bruxism. Technical and mechanical complications were frequent in the probable bruxers (p < 0.05). CONCLUSION: Overall prevalence of bruxism was 19.72%, and bruxism was associated with general and gender-specific predictors.

Effects of nocturnal complete denture usage on cardiorespiratory parameters: A pilot study.

STATEMENT OF PROBLEM: Sleeping without conventional complete dentures (CCDs) has been stated by some to induce negative effects on the cardiorespiratory functions of edentulous patients with obstructive sleep apnea (OSA), although others have reported the exact opposite. Therefore, a consensus on nocturnal CCD usage is lacking. PURPOSE: The purpose of this clinical study was to assess the effects of nocturnal denture usage on cardiorespiratory stability by using pulse oximetry (PO). MATERIALS AND METHODS: Thirty CCD wearers were enrolled in the study. The first nocturnal pulse oximetry (FNPO) recordings were made on 3 different nights while the participants were sleeping without dentures (WOD). Oxygen desaturation index (ODI) and other PO parameters of the participants, including total respiratory event (TRE), basal SpO2 (BSpO2), time≤88 (T88), average low SpO2 (ALSpO2), total pulse event (TPE), average pulse rate (APR), and heart rate variability index (HRVI), were processed and the obtained data were recorded as WOD condition values. According to the ODI scores, the OSA status of the participants was grouped as normal (ODI<5), mild (530). Complete dentures were fabricated by an experienced prosthodontist and a dental laboratory technician by following conventional procedures. At the end of the first month of the follow-up period, the second nocturnal PO recordings (SNPO) were made on 3 different nights while the participants slept wearing dentures (WID), and the data obtained were recorded as WID condition values. The comparison of mean PO values obtained from WOD and WID were analyzed with the Wilcoxon signed- rank test (α=.05). RESULTS: Significant differences were found between WOD and WID values in terms of TRE (P=.01), ODI (P=.001), ALSpO2 (P=.006), TPE (P=.001), and HRVI (P=.001) parameters. The significance of the improvements in the WID condition increased with the severity of OSA. CONCLUSIONS: Improvements were observed in substantial cardiorespiratory parameters such as the ODI and HRVI of the participants wearing dentures nocturnally.

Fabrication of a Mandibular Advancement Device Using a Fully Digital Workflow: A Clinical Report.

Obstructive sleep apnea (OSA) is a common disorder among adults with a potential to be life-threatening. Continuous positive airway pressure is the gold-standard for the treatment of OSA, but patient compliance may be reduced due to various reasons. Mild to moderate cases of OSA can be treated reliably and successfully using oral appliances, and the mandibular advancement device (MAD) is the most frequently used appliance. The aim of this clinical report is to present a fully digital workflow for fabrication of a custom non-adjustable MAD using computer aided design/computer aided manufacturing and additive manufacturing for the treatment of a patient with moderate OSA.

Occupational exposure of dental technicians to methyl methacrylate: Genotoxicity assessment.

Dental technicians may be chronically exposed to methyl methacrylate (MMA), used in the production of dental prostheses. We have studied whether occupational exposure to MMA affects genotoxicity biomarkers such as 8-OHdG formation, comet assay, and buccal micronucleus frequency. MMA exposure was assessed via ambient air analysis. Although no significant differences between exposed and non-exposed individuals were seen with respect to blood genotoxicity measurements, we found a higher level of buccal-cell anomalies in the exposed group.

Can nocturnal use of implant-retained overdenture improve cardiorespiratory stability of a patient with obstructive sleep apnea? A clinical report.

Few studies have evaluated the interaction between conventional complete dentures (CCD) and the respiratory system and the authors are unaware of any that evaluated the interaction between implant-retained overdentures (IROs) and the respiratory system. This clinical report documented the effects of wearing an IRO on the cardiorespiratory stability of an edentulous patient with obstructive sleep apnea (OSA). A 64-year-old woman was referred to the department of otolaryngology because of daytime sleepiness and morning headaches. The patient refused polysomnographic evaluation because of claustrophobia. Overnight pulse oximetry (PO) was performed to detect cardiorespiratory stability during sleep, and the oxygen desaturation index (ODI) of the patient was found to be 20.9. A mandibular advancement device (MAD) was fabricated; however, the patient did not comply with the treatment and stopped using the MAD because of intraoral discomfort. Therefore, the patient started to wear the conventional complete dentures (CCDs) nocturnally to prevent upper airway collapses. Despite the significant drop in ODI score to 12.6, because of displacement, the mandibular denture was converted to an IRO. The PO tests performed after another 6 months revealed an ODI score of 7.8. Wearing CCDs might improve respiratory stability of patients with edentulism during sleep; however, more favorable results could be obtained with IROs.

Effect of dental technician disparities on the 3-dimensional accuracy of definitive casts.

STATEMENT OF PROBLEM: Studies that evaluated the effect of dental technician disparities on the accuracy of presectioned and postsectioned definitive casts are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the accuracy of presectioned and postsectioned definitive casts fabricated by different dental technicians by using a 3-dimensional computer-aided measurement method. MATERIAL AND METHODS: An arch-shaped metal master model consisting of 5 abutments resembling prepared mandibular incisors, canines, and first molars and with a 6-degree total angle of convergence was designed and fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) technology. Complete arch impressions were made (N=110) from the master model, using polyvinyl siloxane (PVS) and delivered to 11 dental technicians. Each technician fabricated 10 definitive casts with dental stone, and the obtained casts were numbered. All casts were sectioned, and removable dies were obtained. The master model and the presectioned and postsectioned definitive casts were digitized with an extraoral scanner, and the virtual master model and virtual presectioned and postsectioned definitive casts were obtained. All definitive casts were compared with the master model by using computer-aided measurements, and the 3-dimensional accuracy of the definitive casts was determined with best fit alignment and represented in color-coded maps. Differences were analyzed using univariate analyses of variance, and the Tukey honest significant differences post hoc tests were used for multiple comparisons (α=.05). RESULTS: The accuracy of presectioned and postsectioned definitive casts was significantly affected by dental technician disparities (P<.001). The largest dimensional changes were detected in the anterior abutments of both of the definitive casts. The changes mostly occurred in the mesiodistal dimension (P<.001). CONCLUSIONS: Within the limitations of this in vitro study, the accuracy of presectioned and postsectioned definitive casts is susceptible to dental technician differences.

Investigation of the oxidative stress condition for occupational exposure to methyl methacrylate.

The purpose of this study is the evaluation of possible toxicological effects on dental personnel, who are exposed to the production materials of prostheses during their entire working life. In this study, the level of methyl methacrylate (MMA) in ambient air was measured as an indicator of external exposure on the personnel. In order to evaluate the possible toxic effects of oxidative stress, which is thought to play an important role in the formation process of many diseases such as cancer, blood samples of volunteers were examined via the ultraviolet-spectroscopic determination of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase antioxidant enzyme activities, comparing occupationally MMA-exposed ( n = 69) and control ( n = 67) groups. In these groups, malondialdehyde (MDA) and glutathione levels were also determined by the same method. The results showed that SOD activity and MDA and glutathione levels were significantly higher in the exposed group when compared with the control group ( p < 0.001). A significant decrease was determined in the glutathione peroxidase activities of the exposed group ( p < 0.05). No significant difference in CAT activities between the groups has been found. When the results obtained in the study are considered, it is suggested that an adaptive response might be developed by dental technicians against low-level MMA exposure.

Can Impression Procedures Affect Certain Vital Functions of Edentulous Patients? A Clinical Study.

PURPOSE: The most suitable treatment conditions and timing for medically unstable patients with severe systemic diseases about to undergo invasive dental treatment are well documented in the literature; however, no medical guides or recommendations identify these conditions for noninvasive dental treatments in such patients. The aim of this clinical study was to determine the effect of impression procedures on arterial oxygen saturation (AOS) and pulse rates (PRs) of edentulous subjects. MATERIALS AND METHODS: A total of 28 Caucasian edentulous participants (15 females, 13 males) were included in the study. Pulse oximetry recordings (150 seconds) were performed for each participant at three stages; recording at rest (CON), during mandibular impressions (MANIs), and maxillary impressions (MAXIs). The mean values of PR, AOS, and event scores (ESs) indicating desaturation were obtained from the records. The comparisons of mean PR and AOS values were performed with the Bonferroni-corrected Wilcoxon-signed ranks test. The ESs were analyzed with the McNemar Test. RESULTS: The mean AOS values of MANI and MAXI did not display significant changes when compared with CON; however, the ESs obtained in both MANI and MAXI were significantly higher than those of CON (p = 0.008, p = 0.004). In addition, mean PR values obtained in MAXI were significantly higher than CON (p = 0.009). CONCLUSIONS: According to the results of this clinical study, the impression procedures may affect the PR values and lead to desaturation events in edentulous patients; however, further studies evaluating blood gas levels, which indicate precise AOS values, are necessary to support the results of this study.

Evaluation of surface roughness and bond strength of quartz fiber posts after various pre-treatments.

PURPOSE: Debonding at the post-adhesive interface is a major problem for quartz fiber posts. The objective of this study was to evaluate surface roughness and bond strength of quartz fiber posts after various surface treatments. MATERIALS AND METHODS: Sixty-six quartz fiber posts were randomly divided into six experimental groups (n = 11) including group C, untreated (control); group SB, sandblasted; group SC, silica coated; group HF, hydrofluoric acid-etched; group N, Nd:YAG laser irradiated; group E, Er:YAG laser irradiated. Surface roughness of the posts was measured before and after pre-treatment. They were then bonded to resin cement and tensile bond strength was determined in a universal testing machine. Furthermore, two-way ANOVA and post hoc comparison tests (α = 0.05) were performed on all data. RESULTS: The highest mean force value was observed in group SB and followed by group E. Tukey's HSD test showed that there was no statistical difference between group SB and group E (p = 0.673). The highest mean roughness value was observed in group SB and a significant difference was found between group SB and all other groups (p < 0.001). This study reveals that sandblasting and Er:YAG laser irradiation provided a significant increase in bond strength between quartz fiber posts and resin cement. CONCLUSIONS: Sandblasting or Er:YAG laser-irradiation of the surface of the quartz fiber post before cementation is recommended for increasing retention.

Effect of different chemical disinfectants on color stability of acrylic denture teeth.

PURPOSE: The purpose of this study was to evaluate the effects of chemical disinfectants on the color stability of acrylic denture teeth (ADT) via spectrophotometric analysis. MATERIALS AND METHODS: A total of 120 central ADT specimens were randomly assigned to eight experimental groups and immersed in the following solutions (n = 15). Tap water/control group (CON), neutral soap (NTS), 2% sodium hypochlorite (SHC1), 5.25% sodium hypochlorite (SHC2), sodium perborate (SPB), povidone-iodine (PVI), chlorhexidine gluconate (CHG), and glutaraldehyde (GTA). Color measurements of teeth were performed by spectrophotometry after 10, 30, 48, 72, 144, and 960 immersion cycles in each tested solution. Color differences (ΔE*) were then evaluated using the Commission Internationale D'Eclairage (CIE) L*a* b* color system. Furthermore, Kruskal-Wallis, Mann-Whitney U, and Friedman comparison tests (α = 0.05) were performed on all data. RESULTS: There were significant differences in ΔE* values (p < 0.05) among the eight experimental groups. In addition, the highest ∆E* values were obtained in group SHC2, followed, respectively, by the SHC1, CHG, SPB, PVI, NTS, and CON groups. CONCLUSION: All the chemical disinfectants used in the study affected the color values of ADTs. Furthermore, ΔE* values increased along with the number of immersion cycles and total immersion time.

Adhesion between glass fiber posts and resin cement: evaluation of bond strength after various pre-treatments.

PURPOSE: To evaluate surface roughness and bond strength of glass fiber posts to a resin cement after various surface treatments. MATERIALS AND METHODS: Sixty individually formed glass fiber posts with a diameter of 1.5 mm and a length of 20 mm were used for this study. They were randomly assigned to six groups of pre-treatment (n = 10/group): Group C, untreated (control); Group SB, sandblasted; Group SC, silica coated; Group HF, hydrofluoric acid-etched; Group N, Nd:YAG laser irradiated; Group E, Er:YAG laser irradiated. Surface roughness of the posts was measured before and after pre-treatment. The posts were then bonded to resin cement and tensile bond strengths were determined in a universal testing machine. For statistical analysis, two-way ANOVA and post-hoc comparison tests (α = 0.05) were performed. RESULTS: The highest bond strength value was observed in group HF, followed by group SC. There was a statistically significant difference in bond strength between group C and groups HF, SC and E (p < 0.001, p = 0.002 and p = 0.041, respectively). Posts of group SB and group N showed the highest surface roughness. CONCLUSIONS: The findings of the present study reveal that hydrofluoric acid-etching, silica coating and Er:YAG laser irradiation provided a significant increase in bond strength between glass fiber posts and resin cement.

Effects of complete dentures on respiratory performance: spirometric evaluation.

OBJECTIVES: There is a lack of data regarding whether edentulous subjects should remove dentures during spirometric measurements or not. The purpose of this study is to determine influences of complete dentures on spirometric parameters in edentulous subjects. MATERIALS AND METHODS: A total of 46 complete denture wearers were included in this study. Respiratory functions of the subjects were evaluated by spirometric tests that were performed in four different oral conditions: without dentures (WOD), with dentures, lower denture only and upper denture only. Forced vital capacity (FVC), peak expiratory flow, forced expiratory volume in 1 s and forced expiratory flow between 25% and 75% were evaluated. The data were analyzed with Friedman, Wilcoxon and paired-samples t tests (α = 0.05). RESULTS: Significant differences were found between spirometric parameters in different oral conditions (p < 0.05). In all spirometric parameters, the most important significant differences were found between conditions WOD, FVC and with lower dentures (FVC), and WOD (forced expiratory volume in 1 s) and with upper dentures (forced expiratory volume in 1 s) (p < 0.001). CONCLUSION: It was observed that complete dentures may unfavourably affect spirometric values of edentulous subjects. However, current findings need to be confirmed with advanced respiratory function tests.

Annealing of Co-Cr dental alloy: effects on nanostructure and Rockwell hardness.

PURPOSE: The aim of the study was to evaluate the effect of annealing on the nanostructure and hardness of Co-Cr metal ceramic samples that were fabricated with a direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS: Five groups of Co-Cr dental alloy samples were manufactured in a rectangular form measuring 4 × 2 × 2 mm. Samples fabricated by a conventional casting technique (Group I) and prefabricated milling blanks (Group II) were examined as conventional technique groups. The DMLS samples were randomly divided into three groups as not annealed (Group III), annealed in argon atmosphere (Group IV), or annealed in oxygen atmosphere (Group V). The nanostructure was examined with the small-angle X-ray scattering method. The Rockwell hardness test was used to measure the hardness changes in each group, and the means and standard deviations were statistically analyzed by one-way ANOVA for comparison of continuous variables and Tukey's HSD test was used for post hoc analysis. P values of <.05 were accepted as statistically significant. RESULTS: The general nanostructures of the samples were composed of small spherical entities stacked atop one another in dendritic form. All groups also displayed different hardness values depending on the manufacturing technique. The annealing procedure and environment directly affected both the nanostructure and hardness of the Co-Cr alloy. Group III exhibited a non-homogeneous structure and increased hardness (48.16 ± 3.02 HRC) because the annealing process was incomplete and the inner stress was not relieved. Annealing in argon atmosphere of Group IV not only relieved the inner stresses but also decreased the hardness (27.40 ± 3.98 HRC). The results of fitting function presented that Group IV was the most homogeneous product as the minimum bilayer thickness was measured (7.11 Å). CONCLUSION: After the manufacturing with DMLS technique, annealing in argon atmosphere is an essential process for Co-Cr metal ceramic substructures. The dentists should be familiar with the materials that are used in clinic for prosthodontics treatments.

Radiofrequency heating and magnetic field interactions of fixed partial dentures during 3-tesla magnetic resonance imaging.

OBJECTIVE: This study evaluated the heating and magnetic field interactions of fixed partial dentures in a 3-Tesla (3T) magnetic resonance imaging (MRI) environment. STUDY DESIGN: Three substructure materials (Co-Cr, Ni-Cr, ZrO2) were used to fabricate twelve 4-retained bridges and 12 crowns. Specimens were evaluated at 3T for radiofrequency heating and magnetic field interactions. One-way analysis of variance (ANOVA) test was used to compare continuous variables of temperature change. Significance was set at P < .05. Translational attraction and torque values of specimens were also evaluated. RESULTS: None of the groups exhibited excessive heating (mean temperature change, < 1.4 °C), with maximum increase at the end of the T-1. Moreover, in all groups, only relatively minor magnetic field interactions that would not cause movement in situ were observed. CONCLUSION: The study findings indicated that patients with fixed partial dentures (single crown or bridge) fabricated from Co-Cr, Ni-Cr, and zirconia substructures may safely undergo MRI at up to 3T.

Conventional multi-slice computed tomography (CT) and cone-beam CT (CBCT) for computer-aided implant placement. Part II: reliability of mucosa-supported stereolithographic guides.

PURPOSE: Deviations of implants that were placed by conventional computed tomography (CT)- or cone beam CT (CBCT)-derived mucosa-supported stereolithographic (SLA) surgical guides were analyzed in this study. MATERIALS AND METHODS: Eleven patients were randomly scanned by a multi-slice CT (CT group) or a CBCT scanner (CBCT group). A total of 108 implants were planned on the software and placed using SLA guides. A new CT or CBCT scan was obtained and merged with the planning data to identify the deviations between the planned and placed implants. Results were analyzed by Mann-Whitney U test and multiple regressions (p < .05). RESULTS: Mean angular and linear deviations in the CT group were 3.30° (SD 0.36), and 0.75 (SD 0.32) and 0.80 mm (SD 0.35) at the implant shoulder and tip, respectively. In the CBCT group, mean angular and linear deviations were 3.47° (SD 0.37), and 0.81 (SD 0.32) and 0.87 mm (SD 0.32) at the implant shoulder and tip, respectively. No statistically significant differences were detected between the CT and CBCT groups (p = .169 and p = .551, p = .113 for angular and linear deviations, respectively). CONCLUSIONS: Implant placement via CT- or CBCT-derived mucosa-supported SLA guides yielded similar deviation values. Results should be confirmed on alternative CBCT scanners.