The crown lengthening double guide and the digital Perio analysis.

OBJECTIVE: This article describes a surgical crown lengthening double guide, which was digitally obtained to improve diagnosis, treatment outcome, and follow-up. CLINICAL CONSIDERATIONS: The rehabilitation of anterior dental esthetics should involve interdisciplinary and facially driven planning for achieving pleasant long-term outcomes. Surgical crown lengthening is one of the most common periodontal surgery, which can be assisted by digital tools to improve surgical planning and follow-up. CONCLUSION: The double guide for surgical crown lengthening allows the proper management of hard and soft tissues for achieving a predefined goal based on biological requirements and facially driven planning. In addition, the digital quality control allows the follow-up compared with the pre-operative condition and planned treatment plan. CLINICAL SIGNIFICANCE: The use of digital tools allow the clinician to develop a facially driven planning with proper communication with the team and patient, leading to a shorter, more predictable, and less invasive surgical technique, reducing postoperative inflammation and increasing patient comfort.

Predictable 3D guided adhesive bonding of porcelain veneers using 3D printed trays.

OBJECTIVE: This clinical report describes a novel digital technique to facilitate and improve the porcelain laminate veneers adhesive bonding procedure using a customized 3D printed guide. CLINICAL CONSIDERATIONS: Porcelain veneers can be stabilized in their fully seated position with a digitally design 3D printed guide before the resin cement is polymerized. The excess cement can be carefully and predictably removed without the risk of dislodgement, rotation or misfit, allowing the clinician to light cure them under controlled pressure in the correct seating position without the risk of fracturing the ceramic material. CONCLUSIONS: Fabricating a custom 3D printed guide for veneer bonding provides significant assistance to an otherwise cumbersome and daunting clinical procedure. CLINICAL SIGNIFICANCE: Adhesive bonding of multiple ceramic veneers is a challenging and technique sensitive procedure. The use of a custom 3D printed guide presented in this article offers a practical aid to achieve a more predictable and precise outcome.

Comparison of visual analog shade matching, a digital visual method with a cross-polarized light filter, and a spectrophotometer for dental color matching.

STATEMENT OF PROBLEM: During the selection of tooth color, subjective communication with the laboratory and an incorrect color registration technique can lead to a poor color match of a restoration to adjacent teeth and oral structures. PURPOSE: The purpose of this cross-sectional study was to compare color registration and color matching in a young Chilean population with 3 different methods: visual with a shade guide, digital visual with a cross-polarized filter, and instrumental with a spectrophotometer. MATERIAL AND METHODS: A total of 60 young volunteers were selected for tooth color registration of the maxillary right central incisor by using 3 different methods. Tooth color registration was performed using the CIELab and ΔE coordinate system. RESULTS: Significant differences were detected between the coordinates recorded by the visual analog method in comparison with the other 2 methods. In contrast, no significant differences were found between the L∗ and b∗ coordinates of the spectrophotometer and the digital visual method with use of a cross-polarization filter. The ΔE obtained between the visual shade and spectrophotometer was 7.35, and the ΔE between the digital visual method with the use of a cross-polarization filter and the spectrophotometer was 6.12. CONCLUSIONS: No statistically significant differences were observed in the digital image with the cross-polarization filter and the spectrophotometer in the L∗ and b∗ coordinate of the CIELab system. In contrast, the visual analog method led to large differences with the other methods under study. The ΔE of the digital visual method with the use of cross-polarization filters and the spectrophotometer was 6.2, considered as an acceptable color mismatch (<ΔE 6.8).

Comparing the use of static versus dynamic images to evaluate a smile.

STATEMENT OF PROBLEM: Smile analysis, as part of the overall facial analysis, is an important component of diagnosis and treatment planning in the esthetic rehabilitation of a patient. Most studies that refer to smile analysis are based on static images. A more comprehensive evaluation can be made with dynamic video images that can be stopped at the most appropriate frame to ensure the best static images for analysis. PURPOSE: The purpose of this clinical study was to evaluate the posed and dynamic smiles of both sexes, considering the type of smile, prevalence of gingival display, dental display at rest, dentogingival display at posed and spontaneous smile, and lip mobility, through digital image acquisition (photographs and video clips) manipulated by using a software program. MATERIAL AND METHODS: Three photographs and 1 video clip were made for each of the 380 voluntary participants aged between 18 and 32 years by using an iPhone 6 iSight 8 MP camera, Moment lens, and artificial 5500 Kelvin light (IceLight). Digital files were evaluated by using a software program (Keynote), determining each point to be evaluated with posed and spontaneous smiles. RESULTS: With static images, 90% of women and 74% of men had gingival display, with only 35% of women and 21% of men having continuous gingival display. With dynamic analysis, these values increased to 100% of women and 95% of men having gingival display and 62% of men and 81% of women having a continuous gingival display (P<.05). The difference between dentogingival display during posed and spontaneous smiles was clear, with 68% of the participants having 2.25 mm more gingival display. Women tend to show slightly more dental display at rest, posed and spontaneous dentogingival display, as well as lip mobility, than men. CONCLUSIONS: The type of smile changes significantly when posed and spontaneous smiles are compared. Women generally show more gingiva and teeth in all the parameters evaluated than men. Dental treatments should be individually planned according to each patient's smile characteristics.

Layperson's preference of the transverse occlusal plane in asymmetric facial model.

OBJECTIVE: Facial asymmetries are common, especially deviated nose and chin. The clinician must consider these variables when establishing the smile, placement and angulation of the occlusal plane. The purpose of this article is to determine if nose and chin deviations affect the perception of laypeople towards different angulations of the occlusal plane cant. MATERIALS AND METHOD: An asymmetric facial model was created from a symmetric facial model used in a previous study. Nose and chin were deviated 3 mm to the left and eight different pictures were created, each with different degrees of occlusal plane cant in both direction. Using a visual Likert scale delivered via Websurvey within the private practice setting, 120 randomly selected laypersons evaluated each image according to their own beauty preferences. RESULTS: In an asymmetric face, nose and chin deviated 3 mm to the left, a minor occlusal plane angulation of 2° can be perceptible regardless of the direction of the cant. CONCLUSIONS: The occlusal plane should be as parallel to the interpupillary line as possible. If occlusal cant is present, less than 2° of angulation it is preferable, regardless of the direction of the nose and chin. CLINICAL SIGNIFICANCE: In the presence of an asymmetric face, the occlusal plane should be as parallel as possible to the interpupillary line. The direction of the deviation of the nose and the chin are irrelevant factors to determine the occlusal plane. An inclination of the occlusal plane can cause vertical discrepancy, which could subsequently create malocclusion. A complete dentofacial analysis can aim at assessing the angulation of the occlusal plane not only for esthetic outcomes, but for also allowing correct occlusal function.

The facial flow concept: An organic orofacial analysis-the vertical component.

Orofacial analysis has been used by dentists for many years. The process involves applying mathematical rules, geometric principles, and straight lines to create either parallel or perpendicular references based on the true horizon and/or natural head position. These reference lines guide treatment planning and smile design for restorative treatments to achieve harmony between the new smile and the face. The goal is to obtain harmony and not symmetry. Faces are asymmetrical entities and because of that cannot be analyzed using purely straight lines. In this article, a more natural, organic, and dynamic process of evaluation is presented to minimize errors and generate harmoniously balanced smiles instead of perfect, mathematical smiles.

Prevalence of tooth forms and their gender correlation.

OBJECTIVE: This study evaluated different tooth shapes from female and male genders, matching them with the firstly proposed pure basic forms, and proposed different hybrid shapes; it also evaluated the percentage of correct gender identification of lay people, dentists and dental students. MATERIALS AND METHODS: Standardized digital photos were taken from 460 people and analyzed by 3 experts regarding genders and tooth forms: pure basic forms-oval (O), triangular (T), square (S) and rectangular (R); and combined hybrid forms-oval-rectangular (OR), triangular-rectangular (TR), triangular-oval (TO), square-oval with flat lateral incisors (SOF), and square-oval with scalloped lateral incisors (SOS). Then, correct gender identification (%) was evaluated among lay people, dentists and dental students (n = 10). RESULTS: Pure forms showed less prevalence in the population studied (O:6.52%; S:3.48%; T:3.26%; R:2.39%) than hybrid ones (TO:20.87%; SOS:20.65%; OR:19.57%; SOF:16.96%;TR: 6.30%). Tooth gender selection among different evaluators was not significantly different (≈50% correct answers). CONCLUSIONS: No correspondence exists between tooth shapes and patient genders. Pre-standardized pure tooth forms appeared less than hybrid ones, while the most frequently found in the population studied were TO, SOS, and OR forms, disregarding genders. CLINICAL SIGNIFICANCE: Esthetic perception is an increasingly important criterion critical to satisfy patients. The correlation of reported tooth shapes with specific genders was not reliably observed in natural smiles. Tooth shapes should be selected according to the wishes of the patient rather than by previously believed gender specific tooth shapes. Pure basic tooth forms should be complemented with the addition of combination forms to more accurately portray forms found in nature.

Layperson's perception of axial midline angulation in asymmetric faces.

OBJECTIVE: Asymmetric facial features such as a deviated nose and chin are common and known to affect smile esthetics. When presented with these asymmetries, the clinician must consider the impact they will have on the smile design parameters-especially the placement and angulation of the dental midline, which is a common starting point for a case involving smile design. The purpose of this article is to determine if the nose and chin deviations affect the perception of dental midline angulation. MATERIALS AND METHODS: An asymmetric facial model (AFM) was created from a digital symmetric facial model, used in a previous study by digitally deviating the nose and chin to the same side. Eight different pictures of this AFM were created, each with different degrees of maxillary midline angulation (both in and against the direction of the deviated nose and chin). Using a visual Likert scaled delivered via Websurvey in the private practice setting, one hundred and ninety-six randomly selected laypersons were asked to evaluate each image according to their own notions of beauty. RESULTS: A minor axial dental midline angulation of 3.5° can be perceived independently of the direction of the cant. All pictures where the midline was canted pointing in the opposite direction of nose and chin deviations presented lower rating mean values. CONCLUSIONS: Off-center noses and chins can influence the perceived attractiveness of a smile with a canted dental midline. The degree and direction of a canted midline can influence the harmony between the smile and overall face, with canting in the same direction of the asymmetric features being rated as more attractive. CLINICAL SIGNIFICANCE: The dental midline should be as vertically straight as possible. If a midline cant is present, however, it is more favorable to have a dental midline angulation which points in the same direction as nose and chin deviations, rather than in the opposite direction.

Distribution of traumatic injuries after the installation of complete dentures in adult patients

Aim Describe the location of traumatic lesions of the oral mucosa that develop after the installation of complete dentures, as well as to quantify the number of post-operative controls that are required. A descriptive study was conducted by examining 84 patients who attended the dental center of Universidad de Los Andes, San Bernardo, during the period from July 2012 to July 2013. A sample of 120 edentulous patients was obtained. After the fabrication and installation of the complete dentures, at least 3 post-operative controls were performed and the location of oral lesions was recorded. Documentation of the association between the patient's clinical variables and the appearance of oral lesions during the first 3 controls was performed using a logistic regression. Results For maxillary dentures, 5 post-operative visits were made and 6 controls for mandible dentures. In the upper jaw the anatomical areas of higher incidence of traumatic injuries were: canine fossa (23.9%), average bridle (23.1%), and distobuccal sulcus (20.1%). In the lower jaw, the highest number of lesions were recorded on the anterior lingual flank (16.5%), anterior and posterior lingual flank (13.4%), and distobuccal sulcus (12.8%). A significant association was observed between subjects who reported consumption of cholesterol-lowering medications and the development of traumatic lesions of the oral mucosa (OR: 0.25 and 95% CI: 0.055-0.939). The installation of complete dentures does not determine that the treatment has ended. Post-operative controls are needed to assess areas of erythema and ulceration.

Objetivo Describir la ubicación y frecuencia de las lesiones traumáticas de la mucosa oral que se generan después de la instalación de las prótesis dentales completas, y cuantificar el número de controles postoperatorios necesarios. Se realizó un estudio descriptivo, examinando a 84 pacientes que asistieron al centro dental de la Universidad de Los Andes, durante el período comprendido entre de julio de 2012 y julio del de 2013. Se obtuvo una muestra de 120 pacientes edéntulos. Después de la fabricación e instalación de las dentaduras completas se realizaron por lo menos 3 controles postoperatorios y la localización de las lesiones orales fue registrada. La documentación de la asociación entre las variables clínicas de los pacientes y la aparición de lesiones orales durante los 3 primeros controles fue realizado por medio de una regresión logística. Resultados Para prótesis maxilar 5 visitas de controles postoperatorios fueron realizados y 6 para mandibulares. En el maxilar superior las zonas de mayor incidencia de lesiones traumáticas fueron: fosa canina (23,9%), flanco medio (23,1%) y distovestibular del surco (20,1%). En la mandíbula se registraron mayor frecuencia de las lesiones en el flanco lingual anterior (16,5%), anterior y posterior (13,4%) y distovestibular del surco (12,8%). Una asociación significativa se observó entre los sujetos que reportaron consumo de medicamentos reductores del colesterol y el desarrollo de las lesiones traumáticas de la mucosa oral (o: 0,25 e IC: 0,055-0,939). La instalación de las prótesis dentales completas no determina que el tratamiento haya terminado. Los controles postoperatorios son necesarios para evaluar las áreas de eritema y ulceración.

Meta-Analysis of the Influence of Bonding Parameters on the Clinical Outcome of Tooth-colored Cervical Restorations.

PURPOSE: To meta-analyze the literature on the clinical performance of Class V restorations to assess the factors that influence retention, marginal integrity, and marginal discoloration of cervical lesions restored with composite resins, glass-ionomer-cement-based materials [glass-ionomer cement (GIC) and resin-modified glass ionomers (RMGICs)], and polyacid-modified resin composites (PMRC). MATERIALS AND METHODS: The English literature was searched (MEDLINE and SCOPUS) for prospective clinical trials on cervical restorations with an observation period of at least 18 months. The studies had to report about retention, marginal discoloration, marginal integrity, and marginal caries and include a description of the operative technique (beveling of enamel, roughening of dentin, type of isolation). Eighty-one studies involving 185 experiments for 47 adhesives matched the inclusion criteria. The statistical analysis was carried out by using the following linear mixed model: log (-log (Y /100)) = ß + α log(T ) + error with ß = log(λ), where ß is a summary measure of the non-linear deterioration occurring in each experiment, including a random study effect. RESULTS: On average, 12.3% of the cervical restorations were lost, 27.9% exhibited marginal discoloration, and 34.6% exhibited deterioration of marginal integrity after 5 years. The calculation of the clinical index was 17.4% of failures after 5 years and 32.3% after 8 years. A higher variability was found for retention loss and marginal discoloration. Hardly any secondary caries lesions were detected, even in the experiments with a follow-up time longer than 8 years. Restorations placed using rubber-dam in teeth whose dentin was roughened showed a statistically significantly higher retention rate than those placed in teeth with unprepared dentin or without rubber-dam (p < 0.05). However, enamel beveling had no influence on any of the examined variables. Significant differences were found between pairs of adhesive systems and also between pairs of classes of adhesive systems. One-step self-etching had a significantly worse clinically index than two-step self-etching and three-step etch-and-rinse (p = 0.026 and p = 0.002, respectively). CONCLUSION: The clinical performance is significantly influenced by the type of adhesive system and/or the adhesive class to which the system belongs. Whether the dentin/enamel is roughened or not and whether rubberdam isolation is used or not also significantly influenced the clinical performance. Composite resin restorations placed with two-step self-etching and three-step etch-and-rinse adhesive systems should be preferred over onestep self-etching adhesive systems, GIC-based materials, and PMRCs.

Bond strength tests of dental adhesive systems and their correlation with clinical results - A meta-analysis.

OBJECTIVE: To evaluate the variability of bond strength test results of adhesive systems (AS) and to correlate the results with clinical parameters of clinical studies investigating cervical restorations. MATERIALS AND METHODS: Regarding the clinical studies, the internal database which had previously been used for a meta-analysis on cervical restorations was updated with clinical studies published between 2008 and 2012 by searching the PubMed and SCOPUS databases. PubMed and the International Association for Dental Research abstracts online were searched for laboratory studies on microtensile, macrotensile and macroshear bond strength tests. The inclusion criteria were (1) dentin, (2) testing of at least four adhesive systems, (3) same diameter of composite and (4) 24h of water storage prior to testing. The clinical outcome variables were retention loss, marginal discoloration, detectable margins, and a clinical index comprising the three parameters by weighing them. Linear mixed models which included a random study effect were calculated for both, the laboratory and the clinical studies. The variability was assessed by calculating a ratio of variances, dividing the variance among the estimated bonding effects obtained in the linear mixed models by the sum of all variance components estimated in these models. RESULTS: Thirty-two laboratory studies fulfilled the inclusion criteria comprising 183 experiments. Of those, 86 used the microtensile test evaluating 22 adhesive systems (AS). Twenty-seven used the macrotensile test with 17 AS, and 70 used the macroshear test with 24 AS. For 28 AS the results from clinical studies were available. Microtensile and macrotensile (Spearman rho=0.66, p=0.007) were moderately correlated and also microtensile and macroshear (Spearman rho=0.51, p=0.03) but not macroshear and macrotensile (Spearman rho=0.34, p=0.22). The effect of the adhesive system was significant for microtensile and macroshear (p < 0.001) but not for macrotensile. The effect of the adhesive system could explain 36% of the variability of the microtensile test, 27% of the macrotensile and 33% of the macroshear test. For the clinical trials, about 49% of the variability of retained restorations could be explained by the adhesive system. With respect to the correlation between bond strength tests and clinical parameters, only a moderate correlation between micro- and macrotensile test results and marginal discoloration was demonstrated. However, no correlation between these tests and a retention loss or marginal integrity was shown. The correlation improved when more studies were included compared to assessing only one study. SIGNIFICANCE: The high variability of bond strength test results highlights the need to establish individual acceptance levels for a given test institute. The weak correlation of bond-strength test results with clinical parameters leads to the conclusion that one should not rely solely on bond strength tests to predict the clinical performance of an adhesive system but one should conduct other laboratory tests like tests on the marginal adaptation of fillings in extracted teeth and the retention loss of restorations in non-retentive cavities after artificial aging.

Osseointegration of zirconia implants: an SEM observation of the bone-implant interface.

BACKGROUND: The successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia (zirconium dioxide, ZrO2) has the potential to become a substitute for titanium as dental implant material. The present study aimed at investigating the osseointegration of zirconia implants with modified ablative surface at an ultrastructural level. METHODS: A total of 24 zirconia implants with modified ablative surfaces and 24 titanium implants all of similar shape and surface structure were inserted into the tibia of 12 Göttinger minipigs. Block biopsies were harvested 1 week, 4 weeks or 12 weeks (four animals each) after surgery. Scanning electron microscopy (SEM) analysis was performed at the bone implant interface. RESULTS: Remarkable bone attachment was already seen after 1 week which increased further to intimate bone contact after 4 weeks, observed on both zirconia and titanium implant surfaces. After 12 weeks, osseointegration without interposition of an interfacial layer was detected. At the ultrastructural level, there was no obvious difference between the osseointegration of zirconia implants with modified ablative surfaces and titanium implants with a similar surface topography. CONCLUSION: The results of this study indicate similar osseointegration of zirconia and titanium implants at the ultrastructural level.