Hydroxyethyl Cellulose Promotes the Mucin Retention of Herbal Extracts Active against Streptococcus mutans.

Streptococcus mutans is considered a major cariogenic bacterium. Most anti-cariogenic dentifrices are limited by a short exposure time. The aim of the present study was to test the hypothesis that adding a mucoadhesive agent to the formulation may increase its bioavailability and efficacy. We tested the effect of adding hydroxyethyl cellulose (HEC) to an herbal extract solution containing lavender, echinacea, sage, and mastic gum, which have been previously shown to be effective against Streptococcus mutans. Mucin-coated wells were treated with four test solutions: saline, herbal extracts, herbal extracts with HEC, and chlorhexidine. The wells were incubated with Streptococcus mutans and studied for biofilm formation (Crystal violet assay), acid production (lactate assay), acid tolerance (ATPase assay), and exopolysaccharide (EPS) production using fluorescent microscopy. The results showed that the addition of HEC to the herbal extract solution caused a significant reduction in Streptococcus mutans biofilm formation, lactic acid production, and EPS quantity (p < 0.001). These results suggest that HEC may be a beneficial added excipient to herbal extracts in an anti-cariogenic formulation.

Does Augmented Visual Feedback from Novel, Multicolored, Three-Dimensional-Printed Teeth Affect Dental Students' Acquisition of Manual Skills?

Although three-dimensional (3D) printing technology is increasingly used in dental education, its application regarding the provision of online visual augmented feedback has not been tested. Thus, this study aimed to: (1) develop two generations of multicolored 3D-printed teeth that provide visual augmented feedback for students conducting the cavity preparation process, (2) assess students' clinical performance after training on the 3D models, and (3) acquire student feedback. For the first-generation model, augmented feedback was obtained from five 3D-printed teeth models for five cavity preparation procedures. Each model comprised three layers printed in green, yellow, and red indicating whether preparation was acceptable, limited, or unacceptable, respectively. The study used a crossover design in which the experimental group trained on five multicolored models and 10 standard plastic teeth, and the control group trained on 15 standard plastic teeth. Students gave positive feedback of the methodology but complained about the printed material's hardness. Therefore, a second-generation model was developed: the model's occlusal plane was replaced with a harder printed acrylic material, and the experiment was repeated. During training, instructors provided external terminal feedback only for performance on standard plastic teeth. Manual grades for cavity preparations on standard plastic teeth were compared. No significant differences were found between the control and experimental groups in both generations' models. However, less instructor time was needed, and similar clinical results were obtained after training with both generations. Thus, multicolored 3D-printed teeth models promote self-learning during the process of acquiring manual skills and reduce student dependency on instructors.

Evaluation of heat conduction in dental implants after exposure to hot beverages.

STATEMENT OF PROBLEM: It is unknown if the consumption of hot beverages after implant placement poses a danger of overheating at the bone-implant interface. PURPOSE: The purpose of this study was to investigate the effect of simulated consumption of hot beverages on the heat transfer to different dental implant types, implant sizes, and the presence of an interim restoration. MATERIAL AND METHODS: A model that consisted of 2 plastic containers was constructed to simulate the oral cavity and endosseous region of the jaw. One-piece and 2-piece implants with abutments were placed into a block of bovine mandibular bone without any healing tissue, surrounded by water maintained at 37°C in the lower compartment. The abutments, which extended into the upper container, were covered with water heated to 60°C to simulate consumption of a hot substance and then were cooled down spontaneously to 37°C during 100 to 600 seconds. Five thermocouple electrodes with an accuracy of ±0.1°C were attached to each test specimen and to a computer with data recording and analysis software to record temperature changes. Repeated measures ANOVA (α=.05)was performed to determine the effect of each major factor. RESULTS: Heat conduction from the abutment exposed to hot liquid was significantly higher in the cervical as opposed to the apical areas of the implants. Implant type (1 piece), diameter (wider), and the absence of an interim coping had a significant effect on the maximum temperature measured and on the temperature change rate. CONCLUSIONS: Abutment exposure to hot liquids resulted in heat conduction to the cervical region of the implant, which could be biologically harmful in healing tissues. Heat conduction was mitigated by implant design and diameter, and by the presence of an interim prosthesis. Results may differ in clinical models.

One-year survival rate outcomes of innovative dental implants: a prospective clinical study.

PURPOSE: The aim of this research was to evaluate an innovative implant design for different placement and loading protocols. The unique implant is a combination of tapered and cylindrical shape, which is aimed to enhance initial stability and long-term osseointegration. MATERIALS AND METHODS: Four hundred and sixty implants were placed in 141 patients under different placement and loading protocols in similarity to those encountered in a dental office. Implants were followed and evaluated for 1 year to assert the survival rate of the newly introduced implant. RESULTS: The results showed a total of 97.4% survival rate, ranging from 92% to 98.6% depending on the different protocols. There was no statistical difference between the different protocol groups. CONCLUSION: The new implant design showed good results for 1 year of follow-up, comparable with the literature, and could be a good choice for every implant-based procedure.

Bone microstrain values of 1-piece and 2-piece implants subjected to mechanical loading.

PURPOSE: The purpose of this study was to measure and compare the strain levels in peri-implant bone as generated by 1-piece (1P) and 2-piece (2P) implant systems. MATERIALS AND METHODS: The implants (1P and 2P) were placed into bovine bone according to the manufacturer's protocol. Four linear strain gauges were placed around each implant neck and apex. Each model was loaded in static loading by a material testing machine in ascending forces ranging from 20 to 120 N. Microstrains (µ[Latin Small Letter Open E]) generated in the surrounding bone were measured by a strain gauge and recorded. RESULTS: Recorded microstrains were significantly higher for 1P implants than for 2P implants. Average recorded microstrain values were significantly lower in the neck (71.6 and 17.3 µs) compared with the apical (132 and 60 µs) regions of 1P and 2P implants, respectively (P < 0.0001). CONCLUSIONS: Within the limitations of this study, highest microstrains were generated in apical regions regardless of implant design, but the 2P implant ap-peared to provide a stress-damping effect in both the cervical and apical regions compared with the 1P implant.

A 10-year retrospective clinical evaluation of immediately loaded tapered maxillary implants.

PURPOSE: The aim of this study was to compare the effects of immediate loading (IL) and delayed loading (DL) on peri-implant crestal bone loss around maxillary implants after long-term functioning. MATERIALS AND METHODS: A retrospective chart review was conducted to assess the outcomes of 110 tapered, multithreaded implants placed for the treatment of one or more missing and/or unsalvageable teeth in the maxilla of 23 patients. Implants were assigned to either the DL or IL database according to loading time. Marginal bone changes were calculated using standardized radiographs taken at implant placement (baseline) and during annual follow-ups. RESULTS: One implant failed in the DL group. After a mean follow-up of 111 months in the DL group and 119 months in the IL group, cumulative implant survival was 99.09% (DL = 98.11%, IL = 100%). No observable bone loss was evident in 83.49% of the surviving implants. Cumulative success rates were 100% for the IL group and 98.11% for the DL group. CONCLUSIONS: Immediately loaded maxillary implants showed long-term results comparable to delayed loaded maxillary implants.

Retrospective clinical evaluation of tapered implants: 10-year follow-up of delayed and immediate placement of maxillary implants.

OBJECTIVES: To retrospectively evaluate the clinical outcome of tapered, multithreaded implants (Tapered Screw-Vent MTX; Zimmer Dental, Inc, Carlsbad, CA) with an emphasis on periimplant crestal bone status around those placed delayed and immediately in the posterior and anterior maxilla. METHODS: Chart reviews were performed on 46 patients who had been treated with 173 implants replacing one or more missing and/or unsalvageable teeth in the maxilla. Implant placement and loading was either immediate or delayed. Marginal bone changes were calculated using standardized radiographs taken at implant placement and during annual follow-up. RESULTS: After a mean follow-up of 119 to 121 months, implant survival rate was 99%, and implant success rate was 97%. No discernable bone loss was evident in 85.5% of the surviving implants. Crestal bone loss was observed in 14.5% of all surviving implants: 38.5% of implants immediately loaded and 29.9% of implants with delayed loading. Twenty-one implants exhibited 1 mm of bone loss, 3 implants lost 2 mm, and 1 implant lost 3 mm. Low-density maxillary jawbone and more extensive bone remodeling required around implants immediately placed into extraction sockets were the probable causes of observed bone loss in this study. CONCLUSIONS: Implants exhibited excellent long-term outcomes with little or no bone loss.

Dentists' knowledge and implementation of the 2007 American Heart Association guidelines for prevention of infective endocarditis.

OBJECTIVES: Our aim was to evaluate the knowledge and implementations of the 2007 American Heart Association guidelines for the prevention of infective endocarditis (IE) among practicing Israeli dentists, 12 months after their publication. STUDY DESIGN: A total of 118 dentists completed a questionnaire regarding required antibiotic prophylaxis for 10 specific cardiac patient subtypes before invasive dental treatment, prophylactic need in at-risk patients for IE in 10 dental procedures, and prophylactic regimen for nonallergic patients. RESULTS: Correct answer response for cardiac conditions was 81.3% (highest failure: mitral valve prolapse [MVP] with regurgitation). There was a consensus among the participants regarding antibiotic regimen for high-risk patients during several dental procedures, such as intraoral radiography, tooth extraction, and periodontal surgery, but a controversy for other procedures. The procedures of disagreement were endodontic treatment, tooth preparation with oral impressions, and restoration of class II caries lesion. Correct antimicrobial agent, dose, and timing were prescribed by 99%, 93.8%, and 100% of the respondents, respectively. CONCLUSIONS: Relatively high level of knowledge of the new guidelines was found among dentists, reflecting both familiarity of the practitioners with the guidelines and acceptance of guidelines. Prophylactic need is ambiguous during restorative, endodontic and prosthetic procedures. Educational resources should emphasize these guidelines, specifically the reduced risk level for MVP with regurgitation patients.