Can Dental Office Lighting Intensity Conditions Influence the Accuracy of Intraoral Scanning?

The aim of this study was to evaluate the influence of different settings of ambient light intensity inside the dental office on the accuracy (trueness and precision) of an intraoral scanner (IOS). A full crown preparation was conducted on a resin molar which was scanned using a high resolution extraoral scanner to obtain a reference model. Six light settings were chosen based on the most clinically relevant light conditions inside the workspace, and the preparation was scanned using an intraoral scanner (PlanScan, Planmeca). The obtained data was analyzed using a professional 3D quality control software (Geomagic Control X). There was no statistically relevant difference between the groups when regarding trueness, although a slight influence of the light intensity could be observed on the trueness values. Regarding precision, the best results were obtained in the 3800 lux group, with the other groups presenting close values, excepting the extreme values (400 lux and 11 000 lux) groups that proved to be the most deficient

Effects of a Hydrogel Patch on Denture‐Related Traumatic Ulcers; an Exploratory Study

PurposeThe aim of this exploratory study was to evaluate the effects of hydrogel patch wound dressing on healing time and pain level of denture‐related lesions of the oral mucosa in edentulous individuals.Materials and MethodsTwenty‐three adults with newly fabricated complete sets of dentures who subsequently developed at least two ulcerative lesions related to their complete dentures were included in the study. For each participant, the smaller lesion (control lesion) was allocated to usual care, that is, adjustment of the denture's margins, whereas the larger lesion (test lesion) was assigned to receive usual care plus application of a hydrogel patch. In the latter, a patch was applied directly on the affected area three times within the first 24 hours, followed by application of three additional patches, namely one during each of the following 3 days. Participants were monitored until complete healing of all ulcers. The primary outcome measures were changes since baseline in each lesion's greatest dimension at days 1 and 7, as well as improvement in ulcer‐related pain experienced.ResultsParticipants were on average about 70 years old, about half were women, and just over 40% had type 2 diabetes. Lesions treated with the hydrogel patch extended between 4.3 and 10.2 mm (mean 7.1 mm) in their greatest dimension, and the smaller lesions receiving usual care were initially 4 mm on average, ranging from 2.0 to 7.0 mm. The hydrogel patch lesions attained 25% to 75% reductions in their greatest lesion extent from baseline to days 1 and 7, respectively, compared to 10% and just over 50% reduction in the lesions that received usual care. Healing rates were similar in patients with and without diabetes. The participants reported significant improvement in pain level 1 day following treatment initiation for 30% of the control lesions, compared to 65% of the lesions treated with the hydrogel patch.ConclusionsThe results of this exploratory study suggest that application of hydrogel patches may represent a novel, effective treatment for accelerating the healing process and pain reduction in mucosal lesions associated with complete dentures also in people with type 2 diabetes; however, larger studies need to confirm these findings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110761/1/jopr12186.pd

Analysis of the Pulpal Blood Flow Microdynamics during Prosthetic Tooth Preparation Using Diamond Burs with Different Degrees of Wear

Pulpal modifications taking place during prosthetic tooth preparation using worn-out burs may represent a risk for the vitality of the dental pulp. The aim of this in vivo study was to evaluate whether the wear of diamond burs has an influence on the vascular microdynamics at the level of the dental pulp, during vertical preparation for zirconia crowns. The study was performed with a split-mouth design and included 32 vital permanent monoradicular teeth (20 maxillary and 12 mandibular), from six subjects, aged between 20 and 50 years. The teeth were randomly assigned to two study groups of 16 teeth each. For prosthetic preparation, new burs were used in the first group, and burs at their 5th use were used in the second group. Four consecutive determinations of the pulpal blood flow by Laser Doppler flowmetry (LDF—laser Doppler MoorLab instrument VMS-LDF2, Moor Instruments Ltd., Axminster, UK) were taken for each tooth included in the study: before the preparation (control values), immediately, at 24 h, and at 7 days after the prosthetic preparation. A four-way ANOVA statistical analysis was applied to analyze the effect of four considered factors (bur wear degree, time of measurement, tooth number, and tooth location) on the pulpal blood flow (PBF). A significant increase in pulpal blood flow compared to the baseline was recorded immediately after preparation (p p p < 0.05) in both groups, but more pronounced in the case of burs at the 5th use. The blood flow was significantly higher in upper jaw teeth, irrespective of the measurement time. In conclusion, the use of worn-out diamond burs produces lasting modifications in the pulpal blood flow of teeth that undergo prosthetic crown preparation. ISRCTN registry: ISRCTN49594720

Scanning Distance Influence on the Intraoral Scanning Accuracy&mdash;An In Vitro Study

Intraoral scanners (IOS) have reached a point where their impact in the dental office cannot be denied. The distance between the tip of the IOS and the preparation may have implications on the accuracy of the digital model. The objective of this study was to evaluate the differences in accuracy between digital impressions in the scenario of different scanning distances. Twenty consecutive scans were performed at five predetermined distances: 5 mm, 10 mm, 15 mm, 20 mm and 23 mm by a single operator. The scanning distance of 10 mm displayed the best accuracy with an overall trueness value of 23.05 &mu;m and precision value of 4.2 &mu;m. The drawn conclusion was that increased scanning distances can decrease the accuracy of a digital impression

Evaluation of the Pulp Chamber Temperature during Tooth Veneer Preparation Using Burs with Different Degrees of Wear—A Preliminary In Vitro Study

The heat produced during tooth preparation could be a source of damage for dental pulp, and many variables are involved in this process. The aim of this in vitro study was to evaluate whether the different degrees of wear of the diamond burs significantly influenced the temperature changes in the pulp chamber during tangential veneer preparation. The sample comprised 30 intact permanent monoradicular teeth, randomly assigned to three study groups of 10 teeth each, of which 5 had the pulp tissue preserved and 5 had thermoconductive paste in the pulp chamber. For prosthetic preparation, we used new burs in the first group, burs at their fifth use in the second group, and burs at their eighth use for the third group. The pulp chamber temperature was evaluated at the start, after one minute, and after three minutes of preparation, using a k-type thermocouple. The results of the three-way ANOVA and Tukey post hoc comparisons showed a highly significant effect of the time of measurement, while the pulp condition and the degree of wear of the burs had no effect. In conclusion, the different degrees of wear of conventional diamond burs do not produce statistically significant different changes in the pulp chamber temperature

The Influence of Hydrofluoric Acid Temperature and Application Technique on Ceramic Surface Texture and Shear Bond Strength of an Adhesive Cement

All-ceramic restorations are the foundation of modern esthetic dentistry. Clinical approaches for preparation, durability, aesthetics, and repair have been reformed by the idea of adhesive dentistry. The aim of the study and the objective question was to evaluate the impact of heated hydrofluoric acid pretreatment and the application technique’s influence on the surface morphology and roughness of leucite-reinforced glass–ceramic materials (IPS Empress CAD, Ivoclar Vivadent), which is fundamental for understanding the adhesive cementation process. Scanning electron microscopy was used to observe the effectiveness of the two HF (Yellow Porcelain Etch, Cerkamed) application techniques and the HF’s temperature impact on the surface topography of the ceramic. Based on surface conditioning methods, the adhesive cement (Panavia V5, Kuraray Noritake Dental Inc., Tokyo, Japan) was applied to the conditioned ceramic samples and light-cured. Shear bond strength values were correlated with the micro-retentive surface texture of the ceramic. With universal testing equipment at a 0.5 mm/min crosshead speed, SBS values between the resin cement and the ceramic material were assessed until failure. Analyzing the fractured surfaces of the specimens by digital microscopy, the failure modes were divided into three categories: adhesive, cohesive, and mixed failure. Analysis of variance (ANOVA) was used to statistically analyze the collected data. The results show that alternative treatment methods affected the material’s surface characteristics and have an influence on the shear bond strength

CAD/CAM CHAIR-SIDE MATERIAL OPTIONS FOR ANTERIOR CROWNS

Aim of the study. This article present today options for materials utilized with chair-side CAD/CAM technology. Selection of the most appropriate material for anterior crowns depends on each individual clinical situation. Materials and methods. Dental ceramics and processing technologies have been significantly improved in recent years, offering to opportunities for different type of restorations. Classification of materials for chair-side CAD/CAM technology is based on different criteria, like microstructure, characteristics, cementation protocol. When anterior region is involved, which case is presented in this article, selecting the most convenient material and following the precise protocol, can lead to smile design enhancement. Conclusions. Successful restorations of frontal teeth with CAD/CAM technology depends on good knowledge and understanding of the materials properties and clinical parameters, together with the precision of every step involved, from preparation, to scanning, designing, milling, to the final adhesive cementation

COMPARISON OF THE FRACTURE RESISTANCE OF ENDODONTICALLY TREATED TEETH RESTORED WITH DIRECT COMPOSITE RESTORATIONS VERSUS ENDOCROWNS- AN IN VITRO STUDY

Aim of the study The aim of the present study was to evaluate the compression resistance of endodontically treated teeth (ETT) restored by using two methods, direct composite restorations and indirect CAD/CAM endocrowns. Material and methods Endodontic treatment were performed on 10 extracted human teeth. After its completion, 5 teeth (Group 1) were restored with Tetric Ceram (Ivoclar Vivadent) composite direct restorations, and 5 with digitally scanned, designed, and milled TetricCAD (Ivoclar Vivadent) composite endocrowns (Group 2) adhesively cemented. Teeth were mechanically tested at compression with the help of a testing machine with an increasing force applied until samples’ fracture. The value of the force was registered for each sample, the means were calculated for each group and a statistical comparison analysis between groups was made. Results The fracture force applied on endocrowns was almost double than the one necessitated for the fracture of teeth restored with direct composite. Conclusions Endocrowns could be recommended as a solution for the restoration of ETT with significant loss of tooth structure due to their increased mechanical resistance