Understanding the Dental Profession's Stress Burden: Prevalence and Implications.

Stress among dental practitioners is highly prevalent and is an issue that demands attention. Dental practice has been linked to mental, physical, chemical, and biological hazards that often foster high stress levels, anxiety, depression, burnout, and potential suicidal ideation. This can lead to unhealthy coping mechanisms and low quality of life, increasing the risk of chronic disease, mental issues, and lower patient care quality. This article summarizes data on stress in dentistry, highlighting its high prevalence and deleterious consequences. Five primary stress dimensions in general dental practice contribute to stress and burnout: productivity, patient-derived issues, regulations, fear of litigation, and work-related aspects. Reducing stress can decrease the risk of chronic conditions and mental health issues and potentially increase dental professionals' health span and career longevity.

Artificial Intelligence and the Future of Dentistry.

"Narrow" artificial intelligence (AI), as opposed to "general" AI, keenly focuses on a single task and performs that task extremely well, such that it is capable of matching expert human performance in quality and far surpassing it in speed. Moreover, narrow AI uncomplainingly accepts tasks that people typically do not want to do, get tired of doing, or make mistakes doing. The AI that is projected to transform dentistry is narrow AI. It is anticipated that AI will bring similar efficiencies to dentistry as those seen in other healthcare areas. Factors that make the dental profession ripe for AI growth include the entrepreneurial and consumer-oriented nature of the profession, the fact that the focus of care is concentrated on a single area of the body, and the rising rate of practice consolidation. One of the effects of AI that is expected to improve patient care is increased consistency in dental diagnoses and treatment. This article provides a general overview of AI and its anticipated impact on the future of dentistry.

Corrigendum: Artificial intelligence in dentistry: current applications and future perspectives.

The following amendments are made to the published article: Quintessence Int 2020;51(3):248-257; First published 4 February 2020; doi:10.3290/j.qi.a43952 Artificial intelligence in dentistry: current applications and future perspectives Yo-wei Chen, DDS, MSc/Kyle Stanley, DDS/Wael Att, DDS, Dr Med Dent, PhD.

Laminate veneers: Preplanning and treatment using digital guided tooth preparation.

OBJECTIVE: The ability to control the reduction of tooth structure in a precise and measurable way during the preparation of ceramic veneers is a clinical challenge. The objective of this article is to introduce a new digital technology that can be used to address this challenge showing its advantages and limitations. First Fit is a digitally guided tooth preparation system that can be used to control the accurate and efficient preparation of teeth. In some cases, the system can be used to prepare the teeth for previously made restorations based on planned digital reduction. CLINICAL CONSIDERATIONS: The First Fit system uses 3D-printed guides and a specially designed handpiece for guided veneer preparation using either a one-step or a two-step approach. In the one-step approach, final restorations are produced prior to preparation of the teeth using reduction guides, and veneers are cemented on the same day as preparation. The two-step approach includes a preparation phase during which the teeth are prepared using a combination of the reduction guides and free hand techniques. Cementation is then completed at a second appointment. CONCLUSION: The First Fit system controls and guides veneer preparation with a minimally invasive approach. In some cases, it enables the production of veneers before tooth preparation, alleviating the need for provisional restorations. CLINICAL SIGNIFICANCE: The guided restorative dentistry technique described here utilizes digital CAD-CAM technology to achieve predictable and accurate results in a minimally invasive and efficient manner.

Artificial intelligence in dentistry: current applications and future perspectives.

Artificial intelligence (AI) encompasses a broad spectrum of emerging technologies that continue to influence daily life. The evolution of AI makes the analysis of big data possible, which provides reliable information and improves the decision-making process. This article introduces the principles of AI and reviews the development of AI and how it is currently being used. AI technology has influenced the health care field because of the need for accurate diagnosis and superior patient care. In order to understand the trend of AI in dentistry, electronic searching was carried out, combined with approaching individual companies to obtain the details of AI-based services. The current applications of AI in clinical dentistry were introduced and summarized. In the future, the AI-based comprehensive care system is expected to establish high-quality patient care and innovative research and development, facilitating advanced decision support tools. The authors believe that an innovative inter-professional coordination among clinicians, researchers, and engineers will be the key to AI development in the field of dentistry. Despite the potential misinterpretations and the concern of patient privacy, AI will continue to connect with dentistry from a comprehensive perspective due to the need for precise treatment procedures and instant information exchange. Moreover, such developments will enable professionals to share health-related big data and deliver insights that improve patient care through hospitals, providers, researchers, and patients.

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.

Mechanical integrity of cement- and screw-retained zirconium-lithium silicate glass-ceramic crowns to Morse taper implants.

STATEMENT OF PROBLEM: The improved esthetics of ceramic dental prostheses has increased their popularity, although their high elastic modulus and low fracture toughness and tensile strength may reduce the long-term performance of dental prostheses. PURPOSE: The purpose of this in vitro study was to assess the mechanical integrity of zirconium-lithium silicate glass-ceramic crowns cement- and screw-retained to a titanium implant-abutment after fatigue. MATERIAL AND METHODS: Forty titanium implants were placed in polyacetal to mimic bone support. Abutments were tightened to the implants to 20 Ncm by using a digital handheld torque meter. The implant abutment assemblies received a pressed maxillary premolar crown, either lithium disilicate (LD) or zirconium-lithium silicate glass-ceramic (LZS). The specimens (n=10) were subjected to fatigue at 200 N and 5 Hz for 500 000 cycles in a Ringer electrolytic solution (37°C). After fatigue, the crowns were removed to evaluate removal torque values on the implant-abutment connection. The remaining crown-implant-abutment assemblies were cross-sectioned at 90 degrees to the implant-abutment joint for inspection of cracks and the micro-gaps by scanning electron microscopy. RESULTS: Removal torque values before fatigue were recorded at 18 ±1.63 Ncm for the LD group and 18.2 ±0.81 Ncm for the LZS group. After fatigue, the removal torque values decreased significantly (12.8 ±1.6 Ncm for LD, 14.9 ±1.08 Ncm for LZS; P<.05). Micro-gaps at the implant-abutment connections were measured at 0.9 ±0.3 µm before fatigue and at 4.2 ±0.9 µm after fatigue. Cracks were detected at the crown adhesive or at the adhesive-abutment interface for both systems after fatigue. CONCLUSIONS: Cement- and screw-retained implant zirconium-lithium silicate glass-ceramic crowns revealed effective fatigue resistance on mean cyclic loading in an electrolyte solution. However, mechanical instability of the crown-adhesive-abutment interfaces and implant-abutment joints was detected after fatigue.

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.

Lip Lifting: Unveiling Dental Beauty.

The focus for the achievement of complete success in the esthetic zone has traditionally been on addressing deficiencies of intraoral hard and soft tissue. Often, these deficiencies are accompanied by esthetic concerns regarding the lips that are routinely neglected by the dental team. A predictable plastic surgery technique - the lip lift - has been used for decades to enhance lip esthetics by shortening the senile upper lip to achieve a more youthful appearance. Over the years, this technique has been refined and used in many different ways, allowing its routine incorporation into full facial esthetic planning. Through restoration of the upper lip to its optimal position, the artistry of the dentist and dental technician can truly be appreciated in the rejuvenated smile. By the introduction of this minimally invasive surgical technique to the dental community, patients stand to benefit from a comprehensive orofacial approach to anterior dental esthetic planning.

Partial-prep bonded restorations in the anterior dentition: Long-term gingival health and predictability. A case report.

Bonded porcelain restorations are a predictable and durable treatment option that can restore not only the strength and function of the teeth but also the esthetic appearance. One important issue in adhesive dentistry is the preservation of sound enamel. Following biomimetic principles, employing minimally invasive applications and adhesive technologies is of paramount importance for successful restorations. While it is widely accepted that minimally invasive restorative techniques should be favored, there is still some controversy over the noninvasive approaches. The purpose of this article is to question the complete "no-prep veneer" concept due to the possible negative effects on periodontal health caused by excessive contour and overhangs of the ceramic restoration, and to propose a new method to assess the quality and longevity of veneers with a partial-prep concept.

The non-vital discolored central incisor dilemma.

The restoration of anterior teeth is frequently a demanding mission. Patients generally have high expectations for the anterior region, which makes the emotional side of treatment especially important. When this involves discolored endodontically treated teeth, consensus can hardly ever be found as to the chosen approach. Bleaching with direct composites is undoubtedly the most conservative choice for these cases. However, this may require more maintenance (touch-up bleaching and repairs) in the long term, which is an important issue for adult patients. On the other hand, bonded porcelain veneers represent a more 'high-end' option, as they recover the original biomechanics of the intact tooth, allow an optimal masking of the substrate, remain stable, and have a reasonable biological cost when compared to full-coverage crowns. This strategy is explained in this article and documented with a clinical case. We describe treatment planning based on the biomimetic concept, taking into consideration what is possible with current materials and techniques when combined with the patient's particular needs, including the introduction of an innovative step during dentin sealing--the microsuction. The laboratory work was totally accomplished by 'teledentistry', with no direct contact between the dental technologist and the patient.

Prevalence of peri-implantitis in patients with implant-supported fixed prostheses.

OBJECTIVE: The purpose of this study was to evaluate periimplantitis prevalence in patients using implant-supported fixed prostheses that did not have any routine maintenance care. METHOD AND MATERIALS: A total of 161 implants (27 patients) were evaluated in patients using implant-supported fixed prostheses. Collected data included information related to patient general health and local factors such as characteristics of implants, time in function, type of loading, positioning, Modified Bleeding Index, bacterial plaque, bleeding on probing (BOP), marginal recession, probing depth (PD), keratinized mucosa, and radiographic bone loss (BL). Factors related to the prostheses were also evaluated. The exclusion criteria were patients that have had any follow-up visit for plaque control of the prosthesis and/or the implants. RESULTS: From a total of 161 implants, 116 (72%) presented without peri-implantitis (PD > 4 mm + BOP + BL > 2 mm) while 45 (28%) had some sign of the disease. Implants placed in the maxilla were 2.98 times more likely to develop the disease (P < .05). Moreover, patients aged ≤ 60 years old were 3.24 times more likely to develop peri-implantitis (P < .05). Another analysis with statistical relevance (P < .05) was that implants with less than 3 mm interimplant distance were three times more likely to have peri-implantitis. There was no statistical relevance considering other analyses. CONCLUSION: It can be concluded that patients aged ≤ 60 years have a greater chance of presenting periimplantitis, as well as for implants positioned in the maxilla and those placed with an interimplant distance < 3 mm.

An approach to biomimetics: the natural CAD/CAM restoration: a clinical report.

Those in the dental field have always pursued the perfect dental material for the treatment of compromised teeth. Gold, amalgam, composite resin, glass ionomer, and porcelain have been used. Tooth-like restorative materials (composite resin and porcelain) combined with an effective hard tissue bond have met the growing demand for esthetic or metal-free restorations in the past 15 to 20 years. However, none of those materials can fully mimic the unique properties of dentin (compliance and crack-stopping behavior) and enamel (wear resistance, function). The aim of this article is to report the restoration of an extensively damaged tooth with a natural restoration obtained by milling an extracted third molar tooth with a computer-aided design and computer-aided manufacturing (CAD/CAM) system. The main benefit of this novel technique is the replacement of lost tissues by actual enamel and dentin, with the potential to recover mechanical, esthetic, and biologic properties. The indication for extracting third molars and premolars because of impaction or for orthodontic reasons makes these posterior teeth readily available. The innovation of the method presented here is the optimal use of the extracted tooth substrate thanks to its positioning technique in the CAD/CAM milling chamber.

Influence of cantilever length and type of arch antagonist on bone loss in total implant-supported prostheses.

This study selected forty-two implants with full arch implantsupported fixed prostheses (with and without a cantilever) with at least five years' loading. Radiographic measurements were performed using Digimizer software (MedCalc Software, Belgium). Bone loss was measured on the distal side of the implant, from the surface of the platform to the edge of the bone crest, and the extent of the cantilever was measured from the distal surface of the last abutment to the end of the metal structure. Three groups were formed according the length of the cantilever: G1: cantilever ≤ 15 mm; G2: cantilever >15 mm; G3: no cantilever. Types of antagonists were grouped as: RP = removable complete denture; FP = fixed implant-supported prosthesis; ND = natural dentition. Data were analyzed according to the length of the cantilever and type of antagonist using Person's test to analyze normality and Student's t-test with P ≦ 0.05. No statistically significant difference was found between G1 and G2; however, increased bone loss was observed in both cantilever groups (G1 and G2) compared to G3 (P> 0.05). The antagonist showed no significant difference in bone loss ( P ≦ 0.05). Cantilevers showed increases in marginal bone loss. The type of antagonist did not influence bone loss.

A new portable vibrator for plaster pouring: effect on the marginal fit at cylinder-abutment.

OBJECTIVE: The aim of this study was to test a new portable vibrator for plaster pouring (developed for this purpose), comparing the effect of its use on the accuracy of working cast of implant-supported restorations to the conventional vibrator. MATERIAL AND METHODS: From a master cast with 2 implants, 30 transfer moldings were made randomly and divided into three groups: group I (GI): pouring performed in an outsourced dental laboratory with conventional plaster vibrator (10 casts), group II (GII): pouring performed in the laboratory of the Federal University of Santa Catarina (UFSC) with conventional plaster vibrator (10 casts) and group III (GIII): pouring performed with the portable vibrator fabricated for this study (10 casts). The position of the analogue and marginal adaptation of the infrastructure were verified by testing the single screw on the master model and on the working model. The measurement of misfit was blindly performed with a precision microscope and analyzing unit, Quadra-Check 200. The data were statistically analyzed by analysis of variance (ANOVA) and the Holm-Sidak test (α=0.05). RESULTS: Means±standard deviations were as follows: GI: 19.19±4.73 µm; GII: 21.72±5.41 µm; GIII: 13.5±2.39 µm (P<0.05), with GIII significantly lower as compared to the other groups. CONCLUSION: Within the limitations of this study, it was concluded that a greater accuracy of working cast was achieved when a portable vibrator was used for casting molds.

A new portable vibrator for plaster pouring: effect on the marginal fit at cylinder-abutment

OBJECTIVE: The aim of this study was to test a new portable vibrator for plaster pouring (developed for this purpose), comparing the effect of its use on the accuracy of working cast of implant-supported restorations to the conventional vibrator. MATERIAL AND METHODS: From a master cast with 2 implants, 30 transfer moldings were made randomly and divided into three groups: Group I (GI): pouring performed in an outsourced dental laboratory with conventional plaster vibrator (10 casts), Group II (GII): pouring performed in the laboratory of the Federal University of Santa Catarina (UFSC) with conventional plaster vibrator (10 casts) and Group III (GIII): pouring performed with the portable vibrator fabricated for this study (10 casts). The position of the analogue and marginal adaptation of the infrastructure were verified by testing the single screw on the master model and on the working model. The measurement of misfit was blindly performed with a precision microscope and analyzing unit, Quadra-Check 200. The data were statistically analyzed by analysis of variance (ANOVA) and the Holm-Sidak test (α=0.05). RESULTS: Means±standard deviations were as follows: GI: 19.19±4.73 µm; GII: 21.72±5.41 µm; GIII: 13.5±2.39 µm (P<0.05), with GIII significantly lower as compared to the other groups. CONCLUSION: Within the limitations of this study, it was concluded that a greater accuracy of working cast was achieved when a portable vibrator was used for casting molds.

Modeling of ultrathin occlusal veneers.

OBJECTIVE: The purpose of this investigation was to compare stresses within bonded porcelain and composite resin ultra-thin occlusal veneers to restore advanced erosive lesions. MATERIALS AND METHODS: A sound maxillary molar was digitized with a micro-CT scanner. The 2D image data were converted in a 3D model using an interactive medical image processing software (Mimics). Standard triangle language files (STL files) of enamel and dentin surfaces were then exported to the software 3-matic to execute design and meshing operations. Solid 3-dimensional (3-D) models acquired in a finite element software (Marc/Mentat) were subjected to nonlinear contact analysis to simulate occlusal loading at 200N and 800N. Values of maximum principal stress and ultimate tensile strength were used to calculate the risk of fracture and for validation with existing experimental data. RESULTS: There were marked differences in stress distributions both at 200N (maximum peak values of 21.59, 28.63, 31.04MPa) and 800N (96.16, 115.73, 134.90MPa) for all restorative materials (MZ100, Empress CAD and e.max CAD, respectively). High tensile stresses (measured in the central groove) were found at 800N with the ceramic occlusal veneers showing occlusal stress peaks 17-29% higher than composite resin. The estimated risk of fracture was decreased for ultrathin composite resin occlusal veneers, which correlated with the existing validation data. SIGNIFICANCE: Ultra-thin composite resin (MZ100) and lithium disilicate (e.max CAD) occlusal veneers represent a conservative alternative to traditional onlays and complete coverage crowns for the treatment of severe erosive lesions in the posterior dentition.