Pre-doctoral dental students' computer-aided design/computer-aided manufacturing-related education, knowledge, attitudes and behavior: A national survey.

OBJECTIVES: Computer-aided design/computer-aided manufacturing (CAD/CAM) technology transformed the world of restorative dentistry. The objectives were to assess pre-doctoral dental students' CAD/CAM-related education, knowledge, attitudes, and professional behavior, and to explore the relationships between the year in dental school and these constructs. METHODS: A total of 358 pre-doctoral dental students from 17 of the 68 US dental schools responded to a web-based anonymous survey. RESULTS: CAD/CAM-related classroom-based education was likely to happen in lectures (87.2%) and simulated exercises as part of a class (86.9%). Faculty were most likely to provide CAD/CAM instruction (87.9%), with staff (44.8%) and dental technicians (20.2%) being engaged as well. Preclinical education included video demonstrations (81.8%), demonstrations during a lecture (76.4%) or for smaller groups of students (69.2%), hands-on workshops (65.6%), and individual instruction (50.4%). Considering the digital workflow in clinics, 45.2% reported using intraoral scans. The more advanced the students were in their program, the more CAD/CAM knowledge (r = 0.27; p < 0.001) and knowledge about what can be fabricated with CAD/CAM technology they had (r = 0.25; p < 0.001). However, the student's satisfaction with the education about CAD/CAM did not increase over the years (r = -0.04; n.s.) and remained neutral, while their attitudes became more positive the longer they were in dental school (r = 0.13; p < 0.05). Their attitudes were quite positive, with most students considering that CAD/CAM is the future of dentistry (5 = most positive: Mean = 4.34), agreeing that they enjoyed working with CAD/CAM (Mean = 4.11) and that CAD/CAM has the potential of making them a better dentist (Mean = 4.07). CONCLUSIONS: The majority of students in the US dental schools appreciate CAD/CAM technology, consider it to be the future of dentistry, and believe it makes them better dentists. The fact that the majority is not satisfied with their classroom-based, preclinical and clinical CAD/CAM-related education should therefore be a call to action to rethink dental school curricula in this content area.

Rationale for Implant Site Preservation With Absorbable Bone Scaffolds

Minimizing alveolar ridge atrophy after tooth removal is crucial for the preservation of the alveolar ridge dimensions for future implant placement and subsequent prosthetic rehabilitation. Methods such as bone grafting have been used extensively but generally focus mainly on maintenance of bone volume and less so on bone quality. To achieve enhanced bone quality, it is important that residual bone graft material particles get replaced by new vital bone. This article describes the rationale for and a technique demonstrating implant site preservation with absorbable bone scaffolding to not only maintain alveolar bone anatomy but also improve bone quality for the long-term stability and success of implant therapy.

Lasso Guided Bone Regeneration Technique for the Management of Implant Fenestration Defects.

Implant placement in the anterior maxilla provides many unique challenges to the clinician, including esthetics and potential alveolar bone anatomic variations. The depth of the implant osteotomy is a key consideration to avoid a fenestration defect, which could necessitate subsequent treatment. Treatment options for such defects include bone augmentation with or without implantoplasty. Bone augmentation for the correction of dehiscence or fenestration defects on restored dental implants can be difficult due to the grafted site being close to the margin of the flap, thereby favoring premature bone graft and/or barrier membrane exposure. This article describes the management of an implant fenestration defect using lasso guided bone regeneration, a contemporary technique for bone augmentation and alveolar reconstruction designed to maximize predictability and tissue quality by combining fast-absorbing bone replacement materials with long-lasting barrier membranes and stabilization with internal periosteal sutures.

Surface Evaluation of Resilient CAD/CAM ceramics after Contouring and Polishing.

OBJECTIVE: This in-vitro study measured the differences in surface roughness for computer assisted design/computer assisted manufacturing (CAD/CAM) resilient ceramic and CAD/CAM composite materials. MATERIALS AND METHODS: The materials included Lava Ultimate (3 M), Cerasmart (GC America), Vita Enamic (Vita Zahnfabrik), and Brilliant Crios (Coltene). One calibrated operator polished each material with three polishing sytems: spiral polishers (Diacomp FeatherLite/Brasseler), rubbercup polishers (Enhance/DentsplyCaulk), and brush-paste (Diashine/VH Technologies). Surface roughness was assessed using a confocal laser microscope (Lext OLS4000/Olympus). RESULTS: A two-way ANOVA revealed statistically significant differences in mean surface roughness values (Sa) among materials and polishers. Tukey multiple comparisons showed that mean Sa values for Lava Ultimate, Enamic, Cerasmart and Brilliant Crios polished with brush-paste as well as Lava Ultimate and Cerasmart values polished with spiral polishers were not significantly different from each other. CONCLUSIONS: The finished surfaces were significantly smoother than milled surfaces for all materials. The brush-paste polishing technique created the lowest surface roughness values for all CAD/CAM materials and values were comparable to what was achieved by spiral polishers for Lava Ultimate and Cerasmart. Rubber polishers did not provide a clinically smooth surface for CAD/CAM resilient ceramic/composite materials. CLINICAL SIGNIFICANCE: The results of the study indicate that polishing creates smooth surfaces for CAD/CAM resilient ceramic and CAD/CAM composite restorations.

Clinical evaluation of chairside Computer Assisted Design/Computer Assisted Machining nano-ceramic restorations: Five-year status.

OBJECTIVES: This investigation was a longitudinal, randomized clinical trial to measure the clinical performance of a nano-ceramic material (Lava Ultimate/3M) for chairside Computer Assisted Design/Computer Assisted Machining (CAD/CAM) fabricated restorations. MATERIALS AND METHODS: One hundred and twenty chairside CAD/CAM onlays were restored with a CEREC system randomly assigned to 60 leucite-reinforced ceramic (IPS EmpressCAD/Ivoclar Vivadent AGBendererstrasse 2FL-9494 SchaanLiechtenstein) onlays and 60 nano-ceramic (Lava Ultimate/3M) onlays. Equal groups of onlays were cemented using a self-etch and a total etch adhesive resin cement. The onlays were recalled for a period of 5 years. RESULTS: At 1 week postoperatively, 10% of the onlays cemented with both the self-etch and total etch adhesive resin cements were reported as slightly sensitive. However, all patients were asymptomatic by the 4th week without treatment. Four leucite-reinforced onlays and one nano-ceramic onlay fractured and required replacement. CONCLUSIONS: Adhesive retention with a self-etch or total etch cementation technique resulted in a similar clinical outcome with no reported debonds. The nano-ceramic onlays had a lower incidence of fracture compared to the leucite-reinforced ceramic onlays with both having a very low risk of fracture. Nano-ceramic onlays performed equally as well as glass ceramic onlays over 5 years of clinical service. CLINICAL SIGNIFICANCE: Ceramic materials have been a mainstay for chairside CAD/CAM restorations for the past 30 years and a new category of resilient ceramics with a resin matrix has been introduced reported to offer ceramic-like durability and esthetics with resin-like efficiency in handling. There are no long-term clinical studies on the performance of these materials. This is a 5-year randomized clinical trial on the performance of nano-ceramic onlays.

Fluoride Levels in Unstimulated Whole Saliva following Clinical Application of Different 5% NaF Varnishes.

The aim of this study was to evaluate the fluoride release from differently formulated 5% NaF varnishes into unstimulated whole saliva in vivo. The fluoride concentration in unstimulated whole saliva was determined after the application of 3 different 5% NaF varnishes (5% NaF, 5% NaF + tricalcium phosphate [TCP], and 5% NaF + amorphous calcium phosphate [ACP]) or a placebo. Fifteen subjects were recruited and enrolled following Institutional Review Board approval based upon the inclusion/exclusion criteria of this study. A cross-over study design was used for the application of either one of the 5% NaF varnishes or a placebo. Unstimulated whole saliva was collected at baseline and at 1, 4, 6, 26, and 50 h following application and analyzed for supernatant ionic fluoride and whole fluoride by microdiffusion. Linear mixed-effects models (5% significance level) were used to determine the effects of varnish and time on the salivary fluoride concentration. The highest amount of fluoride in saliva was found 1 h after application of the fluoride varnishes, with no significant differences among the treatment varnishes with respect to whole fluoride but with lower levels for 5% NaF + ACP in the saliva supernatant. Salivary fluoride levels at 4, 6, and 26 h decreased at each time point and were generally significantly higher for 5% NaF and 5% NaF + TCP. After 50 h, fluoride levels in saliva for all groups were at or below baseline levels. In conclusion, the formulation of other ingredients in fluoride varnishes can affect the fluoride concentration in saliva. The reasons for this phenomenon warrant further investigation since it might affect efficacy of the treatment. This trial is registered at ClinicalTrials.gov (NCT01629290).

The antimicrobial potential of stevia in an in vitro microbial caries model.

PURPOSE: To determine the effect of stevia on caries development when incorporated into a cariogenic diet in a controlled microbial caries model. METHODS: 56 bovine tooth specimens (4 x 4 mm) were divided into four groups, each secured in a caries-forming vessel. All vessels were placed on an electric stirrer inside a 37°C incubator. The specimens were inoculated with Streptococcus mutans, and exposed for 4 days to circulating cycles of tryptic soy broth supplemented with 5% sucrose-TSBS (three x/day), and a mineral wash solution. Between TSBS cycles (three x/day), each group received one of four experimental solutions: phosphate buffer (PBS-negative control), 0.5% stevia solution, 5% stevia solution, or 5% xylitol solution. Development of caries lesions was analyzed using enamel surface hardness. Difference in Vickers Hardness between pre and post-treatment was calculated to determine caries development. Plaque was dislodged from six specimens per group, and the CFU/ml calculated. Data were analyzed using ANOVA at 95% confidence level, and individual group differences calculated using Tukey's test. RESULTS: 5% xylitol resulted in significantly less plaque at the end of the study compared to PBS and 5% stevia, but not significantly different than 0.5% stevia. 5% stevia had significantly softer lesions than the other groups, while there was no significant difference in hardness scores between 5% xylitol, 0.5% stevia and PBS.

Surface Evaluation of Polishing Techniques for New Resilient CAD/CAM Restorative Materials.

PURPOSE: The purpose of this study was to measure the surface roughness of milled chairside computer-assisted design/computer assisted machining (CAD/CAM) restorations using several contouring/polishing systems as to their effectiveness for creating a clinically acceptable surface. MATERIALS AND METHODS: One hundred onlays were milled from monolithic CAD/CAM blocks with an MCXL milling chamber (Sirona Dental) as follows: 30 resin nano-ceramic (Lava Ultimate, 3M ESPE), 30 hybrid ceramic (Enamic, Vita) and 40 leucite-reinforced ceramic (EmpressCAD, Ivoclar). A single group of EmpressCAD onlays was glazed-fired in a porcelain oven (Programat CS2, Ivoclar). Finishing and polishing systems consisted of either an abrasive-polish technique or a brush-polish technique. Roughness values were measured using a three-dimensional measuring laser microscope (OLS4000 LEXT by Olympus). RESULTS: There was a significant difference in the baseline surface roughness of the CAD/CAM materials (p ≤ 0.05), with the resin nano-ceramic (Lava Ultimate) being smoother than the hybrid ceramic (Enamic), and both being smoother than the leucite-reinforced ceramic (EmpressCAD). All polishing techniques resulted in a smoother surface compared with the baseline surface for the leucite-reinforced ceramic (p ≤ 0.05), with both techniques resulting in a significantly smoother surface than glazing in a porcelain oven (p ≤ 0.05). Both polishing techniques resulted in a smoother surface compared with the baseline surface for both the nano-ceramic and hybrid ceramic materials (p ≤ 0.05). CONCLUSIONS: It is possible to create an equally smooth surface for chairside CAD/CAM resilient materials compared with milled ceramics using several finishing and polishing techniques. In general, the polished ceramic surfaces were smoother than the glazed ceramic surfaces. CLINICAL SIGNIFICANCE: The results of the study indicate that it is possible to create an equally smooth surface for chairside CAD/CAM resilient materials compared with milled ceramics using several finishing and polishing techniques. In addition, both polishing techniques resulted in smoother ceramic surfaces when compared to glazed ceramic surfaces. The polished surface of the ceramic material was smoother than the glazed ceramic surface.

The effect of antacid on salivary pH in patients with and without dental erosion after multiple acid challenges.

PURPOSE: To evaluate the effect of antacid swish in the salivary pH values and to monitor the pH changes in subjects with and without dental erosion after multiple acid challenge tests. METHODS: 20 subjects with tooth erosion were matched in age and gender with 20 healthy controls according to specific inclusion/exclusion criteria. Baseline measures were taken of salivary pH, buffering capacity and salivary flow rate using the Saliva Check System. Subjects swished with Diet Pepsi three times at 10-minute intervals. Changes in pH were monitored using a digital pH meter at 0-, 5-, and 10- minute intervals and at every 5 minutes after the third swish until pH resumed baseline value or 45 minutes relapse. Swishing regimen was repeated on a second visit, followed by swishing with sugar-free liquid antacid (Mylanta Supreme). Recovery times were also recorded. Data was analyzed using independent t-tests, repeated measures ANOVA, and Fisher's exact test (α= 0.05). RESULTS: Baseline buffering capacity and flow rate were not significantly different between groups (P= 0.542; P= 0.2831, respectively). Baseline salivary pH values were similar between groups (P= 0.721). No significant differences in salivary pH values were found between erosion and non-erosion groups in response to multiple acid challenges (P= 0.695) or antacid neutralization (P= 0.861). Analysis of salivary pH recovery time revealed no significant differences between groups after acid challenges (P= 0.091) or after the use of antacid (P= 0.118). There was a highly significant difference in the survival curves of the two groups on Day 2, with the non-erosion group resolving significantly faster than the erosion group (P= 0.0086).

Hard and soft tissue changes after crestal and subcrestal immediate implant placement.

BACKGROUND: The purpose of this study is to assess the influence of the placement level of implants with a laser-microtextured collar design on the outcomes of crestal bone and soft tissue levels. In addition, we assessed the vertical and horizontal defect fill and identified factors that influenced clinical outcomes of immediate implant placement. METHODS: Twenty-four patients, each with a hopeless tooth (anterior or premolar region), were recruited to receive dental implants. Patients were randomly assigned to have the implant placed at the palatal crest or 1 mm subcrestally. Clinical parameters including the keratinized gingival (KG) width, KG thickness, horizontal defect depth (HDD), facial and interproximal marginal bone levels (MBLs), facial threads exposed, tissue-implant horizontal distance, gingival index (GI), and plaque index (PI) were assessed at baseline and 4 months after surgery. In addition, soft tissue profile measurements including the papilla index, papilla height (PH), and gingival level (GL) were assessed after crown placement at 6 and 12 months post-surgery. RESULTS: The overall 4-month implant success rate was 95.8% (one implant failed). A total of 20 of 24 patients completed the study. At baseline, there were no significant differences between crestal and subcrestal groups in all clinical parameters except for the facial MBL (P = 0.035). At 4 months, the subcrestal group had significantly more tissue thickness gain (keratinized tissue) than the crestal group compared to baseline. Other clinical parameters (papilla index, PH, GL, PI, and GI) showed no significant differences between groups at any time. A facial plate thickness ≤1.5 mm and HDD ≥2 mm were strongly correlated with the facial marginal bone loss. A facial plate thickness ≤2 mm and HDD ≥3 were strongly correlated with horizontal dimensional changes. CONCLUSIONS: The use of immediate implants was a predictable surgical approach (96% survival rate), and the level of placement did not influence horizontal and vertical bone and soft tissue changes. This study suggests that a thick facial plate, small gaps, and premolar sites were more favorable for successful implant clinical outcomes in immediate implant placement.

Utilization of mandibular tori for alveolar ridge augmentation and maxillary sinus lifting: a case report.

This article reports the utilization of mandibular tori as an alternative source of autogenous bone for ridge augmentation and maxillary sinus lifting to facilitate ideal implant placement. A patient presenting bilateral mandibular tori required replacement of a missing maxillary molar and a mandibular premolar. Both areas showed ridge deficiency that required bone augmentation before implant placement. Mandibular tori were used for horizontal augmentation of the mandibular alveolar ridge and vertical augmentation of the maxillary ridge by elevation of the maxillary sinus. Adequate new bone formation was noted in both areas 6 months after grafting. Bone formed in the grafted areas showed comparable clinical features to those of native bone. Implants were successfully placed and loaded, restoring esthetics and function. Within the limitations of this observation, mandibular tori can be successfully used for ridge augmentation and sinus lifting. However, further controlled studies are needed to determine the overall benefit of this source of autogenous bone.