PubMed ID (PMID): 30302436Pages 459, Language: English
PubMed ID (PMID): 30302437Pages 460-474, Language: English
The mock-up is a diagnostic technique that allows for the intraoral try-in of a prosthetic rehabilitation. Mock-ups facilitate significant improvement in communication with patients by showing them the potential final outcome of the treatment. They also allow for a quick and easy comparison of the pre- and postoperative situations, and permit the clinician to check the functional aspects of the therapy. The purpose of this article is to describe the use of the full-mouth mock-up technique for testing all the functional and esthetic parameters of extensive rehabilitations associated with a VDO increase with completely additive wax-ups. The proposed clinical procedures describe an easy and reversible technique to manage complex prosthetic cases with a more conservative and operator-friendly approach compared with conventional prosthetic therapies, reducing time and costs. All the clinical and technical phases of this approach are described step by step.
PubMed ID (PMID): 30302438Pages 476-492, Language: English
Tooth wear is generally a physiological process; however, it can also be a pathological condition associated with attrition, abrasion, and erosion processes in which the quantity of tooth loss is atypical for the patient's age. Tooth substance loss often causes functional problems, symptoms of discomfort/pain, and esthetic impairments. Patients presenting this condition frequently need restorative treatment, combined with an increase in the vertical dimension of occlusion (VDO). A diagnostic wax-up (DWU) provides assistance in determining a new occlusal plane and VDO, and is a fundamental tool considering the backward planning involved in the execution of a complex rehabilitation. In cases of severe tooth wear, preventive measures must be taken. Yet, when a restorative intervention is needed, the use of a DWU, in conjunction with a mock-up, helps to achieve a predictable and satisfactory outcome. This article presents a case report of a young female patient with pathological tooth wear, related symptomatology, and esthetic complaints. Initially, a DWU and a diagnostic mock-up were created. After esthetic and functional corrections, a second DWU was generated and transferred to the patient's mouth by means of a therapeutic mock-up. This mock-up was used as a trial restoration for the pretreatment phase, to evaluate the new VDO/esthetics/function and to guide tooth preparation. Lithium disilicate (LS2) occlusal onlays were used to stabilize the VDO, and anterior LS2 and feldspathic veneers, combined with direct composite restorations, were executed to reach the planned minimally invasive result.
PubMed ID (PMID): 30302439Pages 494-514, Language: English
Purpose: To determine the most and least attractive smiles from a Brazilian sample and to correlate the anatomical characteristics identified in these smiles.
Materials and methods: Orthodontists, dentists, and laypeople assessed the photographs of 86 students (66 women and 20 men), aged between 19 and 30 years, using a visual analog scale (VAS). An evaluator blinded to the results measured the esthetic composition of the eight photographs with the highest and the eight with the lowest ratings for women, and the two with the highest and the two with the lowest ratings for men. The mean and standard deviations were calculated for the descriptive analysis.
Results: A total of 42 anatomical smile details were identified and described, obtaining the means of the characteristics.
Conclusions: The following characteristics were observed from the selected most attractive smiles: parallel smile arc, oval-shaped incisors with square-rounded edges, increase of the incisal embrasure and reduction of connector space in distal progression, display of maxillary incisors and minimum display of mandibular teeth, gingival margin of central incisors 0.5 mm coronal to the canines and 0.8 mm apical to the lateral incisors, posterior gingival display of 1.5 mm, less than 20% of buccal corridor and display of 12 teeth, and canines with -2 degrees of inclination. The most attractive smiles also had an absence of asymmetries, diastemas, black spaces, incisal plane inclination, and anterior gingival display.
PubMed ID (PMID): 30302440Pages 516-537, Language: English
Following the guidelines of the 'index technique' that were published in this journal in 2015, this article presents the 'digital index technique,' an updated no-prep restorative approach to the management of worn dentition. Patients with minimal, moderate, and severe hard tissue wear can be treated based on the application of minimally invasive or noninvasive adhesive composite restorations on posterior and anterior worn dentition. The technique allows for a purely additive treatment without sacrificing healthy hard tooth tissue. It follows the principles of biodentistry (maximum conservation of healthy tissue), and the reinforcing of residual dental structure. Depending on the severity of the enamel and dentin wear, the number of caries, and the size of the existing restorations, different treatment options can be applied to each tooth: direct and indirect partial restorations or full crowns. It is essential to diagnose and treat tooth surface loss in order to properly restore biomechanics, function, and esthetics by means of adhesive restorations. This article proposes that the update of the index technique through the digital workflow is a fast and conservative approach for the planning and management of a full-mouth adhesive restoration in all cases of light, moderate, and severe worn dentition. The technique is based on a 'copy-and-paste' guided approach, stamping composite resin directly onto the tooth surface by means of a transparent index created from a full-mouth digital restorative wax-up, following an initially planned increase in occlusal vertical dimension (OVD) through an esthetic and functional analysis.
PubMed ID (PMID): 30302441Pages 538-549, Language: English
Purpose: To evaluate and compare light propagation in dental tissues and dental composite restorations using a double-layer build-up technique.
Materials and methods: Natural teeth slabs and dental restoration buildups with A2D and B1E-colored nanofilled, supra-nanofilled, and microhybrid composites were randomized and equally distributed into four experimental groups (n = 10). Using a spectrophotometer, the samples were irradiated by three wavelengths of lasers: red, green, and blue. A voltmeter recorded the light output signal, and the following optical constants were calculated: absorption (A), transmittance (T), and attenuation (K). The data were analyzed using one-way analysis of variance (ANOVA), followed by post hoc Tukey's test (α = 0.05).
Results: Absorption results varied according to the laser color and different composites tested. Regardless of the laser wavelength, the supra-nanofilled composite showed greater light transmittance and lower light attenuation compared with the dental tissues, which was the opposite of the nanofilled composite. The microhybrid composite showed no difference in light transmittance or light attenuation compared with the dental tissues.
Conclusion: Within the limitations of this observational in vitro study, the microhybrid dental composite group had the most similar light propagation pattern compared with natural teeth when using the double-layer build-up technique.
PubMed ID (PMID): 30302442Pages 550-565, Language: English
Purpose: To compare the accuracy of implant impressions using computer-aided impression-making technology and a conventional approach in a standardized setting in vitro, and to verify the effect of implant angulation (40 to 45 degrees) on the accuracy of digital and conventional impression-making procedures.
Materials and methods: Four different edentulous mandibular reference models (RMs) were manufactured. Two straight (RM1); four straight (RM2); two straight and two tilted (RM3); and six straight (RM4) dental implants were placed, simulating four different clinical scenarios. The computer-aided impressions (n = 5 for each RM) were made using an intraoral scanner (IOS) (True Definition, 3M ESPE). Polyether (n = 5 for each RM) and vinyl polysiloxane (n = 5 for each RM) impression materials were utilized for the conventional approach. The collected data were analyzed in terms of trueness. The statistical analysis was performed using one-way analysis of variance (ANOVA).
Results: The overall differences of interimplant distance, identified in mean values, were statistically significant among the different impression-making groups in RM1, RM3, and RM4. The data analyses of overall interimplant angle deviations yielded statistically significant differences in all four RMs. However, the deviations obtained with both impression-making approaches did not exceed an interimplant distance threshold of 100 µm, and an interimplant angle of 0.5 degrees, which seems to be clinically acceptable.
Conclusion: Within the limits of this in vitro study, the accuracy of the computer-aided and conventional impression-making approaches for straight and tilted dental implants was comparable, and might be clinically considered for full-arch, multiple-implant restorations. However, further clinical studies are required to verify the feasibility of different IOSs (with and without scanning powder application), different implant systems, and multiple implant configurations.