Evaluation of different tightening protocols on angled screw channel abutments after cyclic loading: An in vitro study.

STATEMENT OF PROBLEM: Screw loosening remains one of the most common complications associated with implant-supported restorations. The available literature is scarce regarding the most efficient method of tightening definitive abutment screws for angled screw channel (ASC) abutments. PURPOSE: The purpose of this in vitro study was to identify the optimal screw tightening protocol for ASC abutments by evaluating the influence of different protocols on reverse tightening values (RTVs). MATERIAL AND METHODS: Fifty implants were randomly assigned to 5 groups (n=10). Implants were mounted and received a cover screw and impression coping to simulate the clinical scenario. Each group was allocated to one of the following protocols: tightened once (1×), tightened twice (2×), tightened twice at a 10-minute interval (2× [10 min]), tightened, countertightened, then tightened again (TCT) and tightened, countertightened, tightened, countertightened, then tightened (TCTCT). A monolithic zirconia central incisor implant crown was fabricated by using computer-aided design and computer-aided manufacturing (CAD-CAM) and cemented onto the ASC abutment. The crown-abutment assemblies were secured onto the implants with the Gold-Tite abutment screw by using their assigned tightening protocols. Each screw was tightened to the recommended value of 20 Ncm with a calibrated digital torque measuring device. Specimens were subjected to 250 000 cycles of cyclic loading simulating 3 months of function with a universal testing machine. RTV was measured for each specimen. RESULTS: The mean RTV for all the groups ranged from 13.5 Ncm to 15.9 Ncm. The highest mean RTV was found with the (1×) protocol. However, the difference was not statistically significant among any of the groups (P>.05). CONCLUSIONS: Multiple retightening and time intervals between tightening events of these ASC abutment screws did not have a significant influence on RTV under simulated function of 3 months. The one time (1×) tightening protocol can be recommended as a suitable method for ASC abutments, thus avoiding unnecessary retightening.

Evaluating the effects of splinting implant scan bodies intraorally on the trueness of complete arch digital scans: A clinical study.

STATEMENT OF PROBLEM: A predictable protocol for accurately scanning implants in a complete edentulous arch has not been established. PURPOSE: The purpose of this clinical study was to investigate the effect of splinting implant scan bodies intraorally on the accuracy and scan time for digital scans of edentulous arches. MATERIAL AND METHODS: This single center, nonrandomized, clinical trial included a total of 19 arches. Definitive casts with scan bodies were fabricated and scanned with a laboratory scanner as the reference (control) scan. Each participant received 2 intraoral scans, the first with unsplinted scan bodies and the second with resin-splinted scan bodies. The scan time was also recorded for each scan. To compare the accuracy of the scans, the standard tessellation language (STL) files of the 2 scans were superimposed on the control scan, and positional and angular deviations were analyzed by using a 3-dimensional (3D) metrology software program. The Mann-Whitney U test was used to compare the distance and angular deviations between the splinted group and the unsplinted group with the control. The ANOVA test was conducted to examine the effect of the scan technique on trueness (distance deviation and angular deviation) and scan time (α=.05 for all tests). RESULTS: Statistically significant differences were found in the overall 3D positional and angular deviations of the unsplinted and splinted digital scans when compared with the reference scans (P<.05). No statistically significant differences in overall 3-dimensional positional deviations (P=.644) and angular deviations (P=.665) were found between the splinted and unsplinted experimental groups. A faster scan time was found with the splinted group in the maxillary arch. CONCLUSIONS: Conventional complete arch implant impressions were more accurate than digital complete arch implant scans. Splinting implant scan bodies did not significantly affect the trueness of complete arch digital scans, but splinting appeared to reduce the scan time. However, fabricating the splint was not considered in the time measurement.

Evaluation of oral and perioral irritation and sensitization potential of a whitening gel and a whitening toothpaste containing potassium monopersulfate.

PURPOSE: Two clinical trials were conducted to investigate the oral and perioral irritation and sensitization potential of a tooth whitening leave-on-gel alone and in combination with a whitening toothpaste, each containing 1.0% of the active ingredient potassium monopersulfate (MPS). METHODS: Both clinical trials were Institutional Review Board (IRB) approved, double-blind, randomized, and parallel group designed studies. For the MPS leave-on gel study, 200 qualifying and consented subjects were randomly assigned to two groups: (1) 0.1% hydrogen peroxide (H2O2) gel pen (34 subjects); and (2) 0.1% H2O2 + 1.0% MPS gel pen (166 subjects). Subjects used the assigned products according to instructions provided and returned on Days 22 and 36 for oral and perioral tissue examination (pre-challenge). At the Day 36 visit, the subject applied the assigned gel on site (challenge) and received oral and perioral tissue examinations 1 and 24 hours following the application to detect any post-challenge tissue reactions. For the MPS toothpaste/MPS gel pen study, 200 qualifying and consented subjects were randomly assigned to three groups: (1) Placebo toothpaste + placebo gel pen (66 subjects); (2) 1.0% MPS toothpaste + 1.0% MPS gel pen (67 subjects); and (3) 1.0% MPS toothpaste + placebo gel pen (67 subjects). The study design and procedures were the same as those for the MPS gel pen study described above. RESULTS: For the MPS gel pen study, 192 subjects completed the study. None of the eight dropouts was related to the product use. The demographic data were comparable between the two groups. No evidence of tissue irritation and sensitization was detected in any subjects at any visit, and the findings were comparable between the groups. The detected and self-reported tissue issues were minimal and minor, and they were comparable between the two groups. For the MPS toothpaste/MPS gel pen study, 200 subjects were enrolled with 12 dropped from the study, resulting in an overall dropout rate of 6%. Of the 12 that did not complete the study, none were due to product-related use. The demographic data were comparable among the three groups. The detected and self-reported tissue issues were minimal and minor, and they were comparable among the three groups. CLINICAL SIGNIFICANCE: Potassium monopersulfate (MPS) at the active concentration of 1.0% in the tooth whitening leave-on-gel and the toothpaste plus the gel did not cause oral/perioral irritation nor sensitization.

Evaluation of microbial air quality and aerosol distribution in a large dental clinic.

PURPOSE: To evaluate the microbial air quality during dental clinical procedures in a large clinical setting with increasing patient capacity. METHODS: This was a single-center, observational study design evaluating the microbial air quality and aerosol distribution during normal clinical sessions at 5% (sessions 1 and 2) and at > 50% (session 3) treatment capacity of dental aerosol generating procedures. Sessions 1 and 2 were evaluated on the same day with a 30-minute fallow time between the sessions. Session 3 was evaluated on a separate day. For each session, passive air-sampling technique was performed for three collection periods: baseline, treatment, and post-treatment. Blood agar plates were collected and incubated at 37°C for 48 hours. Colonies were counted using an automatic colony counter. Mean colony forming units (CFU) per plate were converted to CFU/m²/h. RESULTS: Kruskal Wallis test was performed to compare the mean CFU/m²/h between the clinic sessions. Statistically significant differences were observed between sessions 1 and 2 (P< 0.05), but not between sessions 2 and 3 (P> 0.05). Combining all clinical sessions, the mean CFU/m²/h were 977 (baseline), 873 (treatment), and 1,631 (post-treatment) for the collection periods. A decrease-to-increase CFU/m²/h trend was observed from baseline to treatment, and from treatment to post-treatment that was observed for all clinic sessions and was irrespective to treatment capacity. Higher amounts of CFU/m²/h were found near the air exhaust outlets for all three clinic sessions. Microbial aerosol distribution is most likely due to the positions and power levels of the air inlets and outlets, and to a lesser extent with patient treatment capacity. CLINICAL SIGNIFICANCE: Dental clinics should be designed and optimized to minimize the risk of airborne transmissions. The results of this study emphasize the need to evaluate dental clinic ventilation systems.

Predictors of fall-related injuries due to common consumer products among elderly adult emergency department visits in the United States during 2007-2017.

Falls are the leading cause of injuries and death among the elderly in the United States (U.S.). This study examined unintentional fall related-injuries and potential associations between various consumer products. Data was analyzed from the National Electronic Injury Surveillance System (NEISS) of hospital emergency department (ED) visits for unintentional injuries among the elderly between 2007 and 2017. Multiple logistic regression was used to examine the association between consumer products and fall-related injury ED visits. A total of 537,703 injury-related ED visits were analyzed. Two-thirds of visits were fall-related. Of those, 33% were among those 85 years and older, 62.5% occurred at home, 37.6% had head trauma, and 28.7% resulted in hospitalization. Flooring materials accounted for 29.1% of injuries. Ladders were significantly associated with fall-related injuries (adjusted odds ratio [AOR] 5.48, 95% confidence interval [CI] 4.72-6.36), followed by flooring materials (AOR 3.09, 95% CI 2.60-3.67), and porches and balconies (AOR 2.61, 95% CI 2.30-2.96). Several common consumer products are associated with fall-related injuries among the elderly. Increased awareness and education are critical.

A randomized, blinded, clinical investigation of breath odor reduction efficacy of a stabilized chlorine-dioxide containing flavored mouthwash.

PURPOSE: To evaluate the efficacy of a flavored, non-fluoridated, alcohol-free mouthwash containing 0.1% chlorine dioxide in reducing oral malodor. METHODS: This was a randomized, 8-week, single site, double blind, crossover design with a 2-week washout period between crossover phases. Fifty subjects with clinically diagnosed intrinsic oral malodor were enrolled according to inclusion/exclusion criteria and randomized to one of two groups. Washout period initiated at end of Phase I and crossover design implemented prior to Phase II. Calibration for organoleptic judges performed at baseline for both phases. RESULTS: 48 subjects completed the study. No significant differences in intensity scores at baseline were found for both groups during both phases (P> 0.05). Within group comparisons for placebo revealed no significant differences with organoleptic intensity scores for all visits during both phases (P> 0.05). During Phase I, the mean changes in organoleptic scores for the test group were significantly different from the baseline at each visit: Weeks 1 to 3 (P< 0.05). After crossover, significant differences were found for the last two visits: Weeks 7 and 8 (P< 0.05). No adverse effects to oral tissues were observed or reported. This product is safe to use for up to 3 weeks and resulted in a decrease in oral malodor. CLINICAL SIGNIFICANCE: Results suggested that twice-daily use of a 0.1% chlorine dioxide-containing flavored mouthwash, in conjunction with normal oral hygiene care, provided clinically relevant improvements in oral malodor for up to 3 weeks.

Enhancement of peripheral seal of medical face masks using a 3-dimensional-printed custom frame.

BACKGROUND: During the COVID-19 pandemic, American Society for Testing and Materials level 3 and level 2 medical face masks (MFMs) have been used for most health care workers and even for the first responders owing to a shortage of N95 respirators. However, the MFMs lack effective peripheral seal, leading to concerns about their adequacy to block aerosol exposure for proper protection. The purpose of this study was to evaluate the peripheral seal of level 3 and level 2 MFMs with a 3-dimensional (3D-) printed custom frame. METHODS: Level 3 and level 2 MFMs were tested on 10 participants with and without a 3D-printed custom frame; the efficiency of mask peripheral seal was determined by means of quantitative fit testing using a PortaCount Fit Tester based on ambient aerosol condensation nuclei counter protocol. RESULTS: The 3D-printed custom frame significantly improved the peripheral seal of both level 3 and level 2 MFMs compared with the masks alone (P < .001). In addition, both level 3 and level 2 MFMs with the 3D-printed custom frame met the quantitative fit testing standard specified for N95 respirators. PRACTICAL IMPLICATIONS: The 3D-printed custom frame over level 3 and level 2 MFMs can offer enhanced peripheral reduction of aerosols when using collapsible masks. With the shortage of N95 respirators, using the 3D-printed custom frame over a level 3 or level 2 MFM is considered a practical alternative to dental professionals.

A clinical investigation of dental evacuation systems in reducing aerosols.

BACKGROUND: The route of transmission of severe acute respiratory syndrome coronavirus 2 has challenged dentistry to improve the safety for patients and the dental team during various treatment procedures. The purpose of this study was to evaluate and compare the effectiveness of dental evacuation systems in reducing aerosols during oral prophylactic procedures in a large clinical setting. METHODS: This was a single-center, controlled clinical trial using a split-mouth design. A total of 93 student participants were recruited according to the inclusion and exclusion criteria. Aerosol samples were collected on blood agar plates that were placed around the clinic at 4 treatment periods: baseline, high-volume evacuation (HVE), combination (HVE and intraoral suction device), and posttreatment. Student operators were randomized to perform oral prophylaxis using ultrasonic scalers on 1 side of the mouth, using only HVE suction for the HVE treatment period and then with the addition of an intraoral suction device for the combination treatment period. Agar plates were collected after each period and incubated at 37 °C for 48 hours. Colony-forming unit (CFU) counts were determined using an automatic colony counter. RESULTS: The use of a combination of devices resulted in significant reductions in CFUs compared with the use of the intraoral suction device alone (P < .001). The highest amounts of CFUs were found in the operating zone and on patients during both HVE and combination treatment periods. CONCLUSIONS: Within limitations of this study, the authors found significant reductions in the amount of microbial aerosols when both HVE and an intraoral suction device were used. PRACTICAL IMPLICATIONS: The combination of HVE and intraoral suction devices significantly decreases microbial aerosols during oral prophylaxis procedures.

Computational Biomechanical Analysis of Engaging and Nonengaging Abutments for Implant Screw-Retained Fixed Dental Prostheses.

PURPOSE: To evaluate the stress distribution, using 3-dimensional finite element analysis (FEA), on different implant components of a mandibular screw-retained fixed dental prosthesis (FDP) situation when using different combinations of engaging and nonengaging abutments. MATERIAL AND METHODS: A model of artificial bone was digitally designed. Dental implants were positioned in the lower right posterior area of teeth #'s 28 (premolar - pm) and 30 (molar - m). Restorative implant components were digitally designed and placed into the implant model. Four different implant abutment situations were simulated through FEA: (1) Both engaging abutments (mE-pmE), (2) both nonengaging (mNE-pmNE), (3) molar nonengaging and premolar engaging (mNE-pmE), and (4) molar engaging and premolar nonengaging (mE-pmNE). Thirty-five (35) Ncm preload to the abutment screws and 160 N static load at 45° angle to the occlusal plane were applied in each group. RESULTS: The equivalent Von Mises stress was measured on each component. Stress distribution changed among the different configurations and ranged from 516.0 to 1304.6 MPa in the implants, and from 554.6 to 994.5 MPa with the abutments. Higher stress was found for the mNE-pmNE designs (1078.6-1106.9 MPa). Engaging and nonengaging abutments had different stress distributions on the screw (698.8-902.5 MPa). Peak stress areas were located on the upper part of the screws for the nonengaging configuration, and on the lower areas for the engaging abutments. The sum of the stress on both implants decreased in the following order: mNE-pmNE > mE-pmNE > mNE-pmE > mE-pmE. CONCLUSION: Under conditions of this study, abutment design produced different stress patterns to the implant components. The lowest and most balanced stress distribution was found for the mE-pmE configuration followed by the mNE-pmE configuration.

Influence of Tooth Preparation Design and Scan Angulations on the Accuracy of Two Intraoral Digital Scanners: An in Vitro Study Based on 3-Dimensional Comparisons.

PURPOSE: To evaluate the accuracy of two intraoral scanners (IOS) in terms of different preparation designs and scan angulation limitation due to the presence of adjacent teeth. MATERIALS AND METHODS: Eight different complete coverage (CC) and partial coverage (PC) tooth preparations were scanned by two IOS, the 3Shape TRIOS (TRI) and the 3M True Definition (TRU). All teeth preparations were scanned in the presence and absence of adjacent teeth. Four groups were established for each IOS; Group 1: PC preparations with adjacent teeth. Group 2: CC preparations with adjacent teeth. Group 3: PC preparations without adjacent teeth. Group 4: CC preparations without adjacent teeth. 3D analysis was performed to examine average absolute discrepancy (AAD) and maximum absolute discrepancy (MAD). A Two-way ANOVA was performed followed by a post-hoc Tukey's test HSD to evaluate the effect of adjacent teeth, preparation design, and the type of IOS used. RESULTS: For TRI, AAD for groups 1, 2, 3, and 4 were 20 ± 1.8 µm, 19.6 ± 2.4 µm, 15.5 ± 2.7 µm, and 12.9 ± 1.4 µm, respectively, whereas MAD for groups 1, 2, 3, and 4 were 109.7 ± 13.5 µm, 93.2 ± 28.9 µm, 85.6 ± 16.1 µm, and 66 ± 20.1 µm, respectively. For TRU IOS, AAD for groups 1, 2, 3, and 4 were 22.0 ± 3.6 µm, 17.9 ± 2 µm, 20 ± 5.9 µm, and 14.9 ± 1.7 µm, respectively, whereas the MAD for groups 1, 2, 3, and 4 were 151.4 ± 38.4 µm, 92.2 ± 17. µm, 92.6 ± 23.6 µm, and 71.4 ± 11.9 µm, respectively. Two-way ANOVA showed statistically significant differences between the AAD and MAD of TRI and TRU (p < 0.001). There were also statistically significant differences for presence or absence of adjacent teeth (p < 0.001), and preparation design (p < 0.001). CONCLUSIONS: PC preparation scans revealed lower accuracy than CC. The presence of adjacent teeth decreased the accuracy of both IOS. TRI gave higher accuracy than TRU for PC, but both IOS showed comparable accuracy for CC groups.

Effect of Crown Preparation Height on Retention of a Prefabricated Primary Posterior Zirconia Crown.

Purpose: The purpose of this study was to evaluate the retention strength of prefabricated zirconia crowns for primary teeth with various crown preparation heights. Methods: Seventy-five extracted human teeth were prepared to have remaining occluso-cervical heights (OCH) of one mm, two mm, three mm, and four mm. Prefabricated posterior zirconia crowns (EZCrown) were cemented with glass ionomer cement. All groups were thermocycled, except for the nonthermocycled control group, which had three mm OCH. Instron E3000 was used for the pullout test. One-way analysis of variance (ANOVA) with Least Significant Difference post hoc test (P<0.05) were performed. Results: The means for the one-mm, two-mm, three-mm, and four-mm thermocycled groups were 1.7±1.0 MPa, 2.9±1.4 MPa, 3.1±0.7 MPa, and 3.3.0±0.6 MPa, respectively. The mean for the nonthermocycled control three-mm group was 2.7±0.8MPa. A significant difference in retention within the four thermocycled groups was observed (one-way ANOVA, P<0.001). Conclusions: The zirconia crown retention force is closely related to occluso-cervical heights. Two millimeters OCH is crucial for prefabricated zirconia crown retention. (Pediatr Dent 2019;41(3):229-33) Received November 14, 2018 | Last Revision February 25, 2019 | Accepted March 5, 2019.

A Randomized Parallel Study to Assess the Effect of Three Tongue Cleaning Modalities on Oral Malodor.

OBJECTIVES: The objective of this study was to compare the effects of three tongue hygiene regimens on oral malodor. METHODS: This was a single-center, randomized, parallel design study with three treatment groups. Subjects were randomly assigned to perform tongue hygiene with either the Philips Sonicare TongueCare+ BreathRx regimen (STC), Listerine Cool Mint antiseptic rinse (LCM), or tongue brushing with an ADA reference manual toothbrush (MTB). Tooth brushing was standardized for all subjects during the study period, and no other oral or breath hygiene measures were allowed. Eligible subjects met the following criteria: aged 18-70 years, in good general and oral health, non-smoker, with an organoleptic score between 2.7 and 4.5 following a 12-18 hour oral hygiene abstention period. Subjects who had oral appliances or who had periodontal disease or excessive recession were not eligible. The primary endpoint analysis was to evaluate oral malodor based on an organoleptic (OL) score. Additional surrogate measures for oral malodor included quantification of oral hydrogen sulfide (H2S) level and counts of oral bacteria in secondary analyses. At Day 1, all three malodor endpoints were assessed prior to product use, immediately after use, and four and eight hours after use. Subjects were then provided with instructions on product use at home. Subjects returned to the clinic on Day 8 and the assessments for malodor were repeated for each of the three endpoints, i.e., prior to in-clinic use of the products, immediately after use, and four and eight hours after use. RESULTS: One hundred sixty-eight (168) subjects were randomized to three groups, with 56 per treatment group. Of these, 165 completed all study visits. Randomized subjects were comparable for baseline characteristics (OL score, age, race, and ethnicity). Overall, oral malodor based on the organoleptic score decreased for all treatment groups at all timepoints. For the primary endpoint, reduction of OL score eight hours following a single product use, the STC regimen reduced malodor per OL score by 46.67% (SE = 2.28%), the LCM value was 22.83% (SE = 2.29%), and MTB was 26.19% (SE = 2.29%). The pair-wise comparisons between STC and each of the treatment groups were statistically significant (p-values < 0.0001). Statistically significant differences were also observed between STC and both LCM and MTB groups in pair-wise comparisons at Day 8 (p-values < 0.0001). CONCLUSIONS: Reductions in malodor were evident following a single use of each product, and also following a seven-day repeat use period. The STC regimen, however, was statistically significantly superior to both LCM and MTB at improving malodor eight hours following the first use. Statistically significant differences in OL scores were sustained between STC and LCM, and STC and MTB at each efficacy timepoint following the seven-day home use period.

Solving the problem with stannous fluoride: Extrinsic stain.

BACKGROUND: This article highlights a stabilized stannous fluoride (SnF2) dentifrice that, in addition to being efficacious against caries, gingivitis, and dentin hypersensitivity, demonstrates high-performing stain prevention and removal efficacy. METHODS: An in vitro stain prevention model evaluated the efficacy of Colgate TotalSF containing 0.454% SnF2 and 1% zinc phosphate compared with Crest Pro-Health Whitening Power (The Procter & Gamble Company) and a nonabrasive SnF2 gel. L*, a*, and b* values were measured to assess whiteness comparing untreated and stained teeth, and with statistical analysis. A stain removal clinical study was conducted as a randomized, double-blind, 2-cell, parallel-group design using Colgate TotalSF and nonwhitening regular fluoride toothpaste. Participants were instructed to brush twice daily for 6 weeks and were examined for Lobene Composite Stain Index scores, with statistical analysis used at a significance of P < .001. RESULTS: In an in vitro stain prevention study, Colgate TotalSF performed 26% and 35% better than a competitor paste and nonabrasive SnF2 gel, respectively. In a clinical study, Colgate TotalSF use showed statistically significant extrinsic tooth stain reductions by 17.5% (3 weeks) and 27.8% (6 weeks) relative to regular fluoride toothpaste. No adverse effects were reported. CONCLUSIONS: The results indicate that the stabilized Colgate TotalSF performed statistically better than other SnF2 pastes in an in vitro study, and statistically better than a regular fluoride toothpaste in a clinical study. PRACTICAL IMPLICATIONS: Colgate TotalSF offers an SnF2-based therapeutic dentifrice with notable performance in stain prevention and removal.

An In Vitro Investigation of Accuracy and Fit of Conventional and CAD/CAM Removable Partial Denture Frameworks.

PURPOSE: To evaluate the overall accuracy and fit of conventional versus computer-aided design/computer-aided manufactured (CAD/CAM) removable partial denture (RPD) frameworks based on standard tessellation language (STL) data analysis, and to evaluate the accuracy and fit of each component of the RPD framework. MATERIALS AND METHODS: A maxillary metal framework was designed for a Kennedy class III Modification I arch. The master model was scanned and used to compare the fit and accuracy of RPD frameworks. Forty impressions (conventional and digital) of the master cast were made and divided into 4 groups based on fabrication method: group I, lost-wax technique (conventional technique), group II, CAD-printing, group III, CAD-printing from stone cast, and group IV, lost-wax technique from resin-printed model. RPD frameworks were fabricated in cobalt-chromium alloy. All frameworks were scanned, and the gap distance between the framework and scanned master model was measured at 8 locations. Color mapping was conducted using comprehensive metrology software. Data were statistically analyzed using the Kruskall-Wallis test, followed by the Bonferroni method for pairwise comparisons (α = 0.05). RESULTS: Color mapping revealed distinct discrepancies in major connectors among the groups. When compared to 3D-printed frameworks, conventional cast frameworks fabricated using dental stone or printed resin models revealed significantly better fit (p < 0.05) particularly in the major connectors and guide plates. The biggest gap (0.33 mm ± 0.20 mm) was observed with the anterior strap of the major connector with the printed frameworks (groups II and III). The method of fabrication did not affect the adaptation of the rests or reciprocation plates. CONCLUSIONS: Although both conventional and 3D-printing methods of framework fabrication revealed clinically acceptable adaptation, the conventional cast RPD groups revealed better overall fit and accuracy.

An in vitro evaluation of the maxillary occlusal plane orientation obtained with an electronic application: A preliminary investigation.

STATEMENT OF PROBLEM: In the evaluation and fabrication of dental prostheses, maxillary occlusal plane orientation in the sagittal and coronal planes may affect functional and esthetic outcomes. The accuracy of a recently developed electronic application in transferring this orientation to a semiadjustable articulator has not been evaluated. PURPOSE: The purpose of this in vitro study was to evaluate the coronal and sagittal orientation of the occlusal plane on maxillary casts mounted with an electronic application facebow system onto a corresponding semiadjustable arcon articulator. MATERIAL AND METHODS: A maxillary typodont was placed into a phantom head (control) oriented with the Frankfort horizontal plane parallel to the horizon. A digital protractor was used to measure the angle between the occlusal plane of the maxillary arch of the phantom head and the Frankfort horizontal plane along the sagittal and coronal planes. The commercial system (test group) was used to make 15 facebow records of the maxillary typodont within the phantom head. The system records were used to mount diagnostic casts of the maxillary typodont onto a semiadjustable arcon articulator. The same measurements were made on the mounted diagnostic casts and were compared with the control. Statistical differences between the occlusal plane of the control and the occlusal plane of the mounted maxillary casts were determined using the 1-sample t test (α=.05). RESULTS: The coronal orientation of the occlusal plane was significantly different (P<.001) between test group and control. No significant differences (P>.05) were found in the sagittal orientation of the occlusal plane. CONCLUSIONS: Within the limitations of this study, variations in the coronal plane orientation were observed with the system. Variations in this plane may lead to adverse evaluation and clinical outcomes.

Efficacy of stabilized chlorine dioxide-based unflavored mouthwash in reducing oral malodor: An 8-week randomized controlled study.

PURPOSE: To evaluate the efficacy of a mouthwash containing stabilized chlorine dioxide in reducing oral malodor when used as an adjunct to tooth brushing compared with the use of a placebo mouthwash. METHODS: This 8-week study in healthy subjects with clinically diagnosed intrinsic oral malodor was a 2-way crossover, double-blind, randomized, and controlled trial design, which was conducted at a single site. Subjects were randomized to receive either unflavored, non-fluoridated, and alcohol-free mouthwash containing 0.1% stabilized chlorine dioxide or a placebo mouthwash with identical bottle packaging. Both groups were provided with the same toothpaste and toothbrush. Subjects consented to the 8-week participation and were instructed to use their allocated treatment twice daily. In Phase I, quantified odor intensity [measured by an organoleptic intensity rating scale of 0-5, with 0=malodor cannot be detected and 5=very strong malodor] was independently evaluated by three calibrated judges at baseline, and after 1, 2, and 3 weeks of treatment. Following a 2-week washout period, Phase II initiated with the redistribution of test products. The subjects' organoleptic scores were assessed by the calibrated judges at baseline, and 6, 7, and 8 weeks of treatment. RESULTS: A total of 50 subjects were enrolled and randomized into the two groups. Of these, 47 subjects completed the study. The baseline organoleptic intensity scores for both groups during Phase I and Phase II were not significantly different (P= 0.224, P= 0.071, respectively). At all visits, the organoleptic scores for the placebo rinse group during both Phase I and Phase II were not significantly different. During Phase I, the mean of individual organoleptic change scores from the stabilized chlorine dioxide rinse group were significantly different from the baseline at the last two follow-up visits:Week 1 (P= 0.088), Week 2 (P= 0.001), Week 3 (P= 0.1×10-3). During Phase II, the mean of individual organoleptic change scores from the stabilized chlorine dioxide rinse group were also significantly different from the baseline at the last two follow-up visits: Week 6 (P= 0.120), Week 7 (P= 0.004), Week 8 (P= 0.002). CLINICAL SIGNIFICANCE: The results of this study suggest the daily use of a stabilized chlorine dioxide-containing unflavored mouthwash as an adjunct to brushing with fluoride toothpaste provides a clinically relevant reduction in oral malodor after 3 weeks of twice-daily use.

In vitro comparison of the maxillary occlusal plane orientation obtained with five facebow systems.

STATEMENT OF PROBLEM: The sagittal and coronal orientation of the maxillary occlusal plane plays an important role in the esthetic and functional outcome of dental prostheses. The accuracy of contemporary facebow transfer systems in transferring this orientation to semiadjustable articulators has not been quantified. PURPOSE: The purpose of this in vitro investigation was to analyze the sagittal and coronal orientation of the occlusal plane with 5 different facebow transfer systems. MATERIAL AND METHODS: A phantom head containing a maxillary typodont (control) was oriented so that the Frankfort horizontal plane was horizontal. The angle between the occlusal plane of the maxillary arch of the phantom head and the Frankfort horizontal plane was measured along the sagittal and coronal planes with a digital protractor. Fifteen facebow records using each of 5 facebow transfer systems (test groups) were made on the phantom head containing the maxillary typodont. Diagnostic casts of the maxillary typodont were mounted on semi-adjustable arcon articulators from the facebow records. The same angles measured on the control were measured on the test groups. These angles were compared with the same angle measured on the maxillary arch of the phantom head (control). All measurements were made by 2 operators. RESULTS: Significant differences in the sagittal and coronal orientation of the occlusal plane were noted. Compared with the control, the Denar system had the least significant difference in the coronal orientation of the occlusal plane, while the Pana-Mount system had the least significant difference in the sagittal orientation of the occlusal plane. An intergroup comparison of the test groups showed significant differences among the groups. The Kois system showed the greatest difference in the coronal plane orientation, while the Denar system showed the greatest difference in the sagittal plane orientation. CONCLUSIONS: None of the tested facebow systems exactly replicated the sagittal and coronal orientation of the maxillary occlusal plane. Significant differences in the sagittal and coronal orientation of the occlusal plane were observed between the test groups and the control. Intergroup comparisons revealed significant differences in the sagittal and coronal orientation of the occlusal plane.

Effect of disinfection on irreversible hydrocolloid and alternative impression materials and the resultant gypsum casts.

STATEMENT OF PROBLEM: Many new products have been introduced and marketed as alternatives to traditional irreversible hydrocolloid materials. These alternative materials have the same structural formula as addition reaction silicone, also known as vinyl polysiloxane (VPS), impression materials. Currently, there is limited in vitro and in vivo research on these products, including on the effects of chemical disinfectants on the materials. PURPOSE: The purpose of this study was to compare the effects of a spray disinfecting technique on a traditional irreversible hydrocolloid and 3 new alternative impression materials in vitro. MATERIAL AND METHODS: The tests were performed in accordance with the American National Standards Institute/American Dental Association (ANSI/ADA) Specification Nos. 18 and 19. Under standardized conditions, 100 impressions were made of a ruled test block with an irreversible hydrocolloid and 3 alternative impression materials. Nondisinfected irreversible hydrocolloid was used as the control. The impressions were examined for surface detail reproduction before and after disinfection with a chloramine-T product. Type III and Type V dental stone casts were evaluated for linear dimensional change and gypsum compatibility. Comparisons of linear dimensional change were analyzed with 2-way ANOVA of mean ranks with the Scheffé post hoc comparisons (α=.05). Data for surface detail reproduction were analyzed with the Wilcoxon Signed-Rank procedure and gypsum compatibility with the Kruskal-Wallis Rank procedure (α=.05). RESULTS: The alternative impression materials demonstrated significantly better outcomes with all 3 parameters tested. Disinfection with chloroamine-T did not have any effect on the 3 alternative impression materials. The irreversible hydrocolloid groups produced the most variability in the measurements of linear dimensional change. All of the tested materials were within the ADA's acceptable limit of 1.0% for linear dimensional change, except for the disinfected irreversible hydrocolloid impression material. CONCLUSIONS: The alternative impression materials performed best for the parameters tested. Spray disinfection had no effect on the alternative impression materials.