Incisal Edge Research Articles

Clearly fluorescent delineating ER+ breast tumor incisal edge and identifying tiny metastatic tumor foci at high resolution.

Fluorescence-image guided surgery (FGS) can intraoperatively provide real-time visualization of a tumor incisal edge and high-resolution identification of tumor foci to improve treatment outcomes. In this contribution, we report a fluorescent probe NB-TAM based on intramolecularly folded photoinduced electron transfer (PET), which displayed a prominent turn-on response in the near-infrared (NIR) window upon specific interaction with the estrogen receptor (ER). Significantly, NB-TAM could delineate a clear tumor incisal edge (tumor-to-normal tissue ratio > 5) in a 70-min time window, and was successfully used to guide the facile and precise resection of ER+ breast tumors in mice. To our surprise, NB-TAM was found to be capable of identifying very tiny lung metastatic ER+ breast tumor foci (0.4 × 0.3 mm), and this ultrahigh resolution was essential to effectively promote tumor resection precision and early diagnosis of tiny tumors. These results clearly elucidate the promising application of NB-TAM as a diagnostic agent for intraoperative fluorescence imaging of ER+ breast cancer.

In Vitro Aging and Fracture Tests on Differently Veneered Partially Stabilized Zirconia Anterior Crowns.

Objectives: To evaluate the fracture resistance of veneered incisor crowns made from highly translucent zirconia frameworks. Materials and Methods: Ninety-six all-ceramic single crowns were based on either a coping with minimum wall thickness or a cutback framework fabricated from highly translucent zirconia (5Y-PSZ). Each one-third of the specimens was finalized with different veneering ceramics using standardizations and glaze firing. Crowns were luted to cobalt-chromium dies with MDP-containing composite cement. Half of the entire sample underwent artificial aging (chewing simulation and thermocycling) before fracture load tests were conducted using a 6 mm steel sphere applied in a 90° angle to the oral aspect of the crowns with 1.3 mm distance to the incisal edge. Besides descriptive presentation of recorded forces at first damage (F1d) and fracture (Fu), Kruskal Wallis and Mann-Whitney U tests were used to analyze data at α = 0.05. Results: Directly after manufacturing, incisor crowns of all test groups showed sufficient mean fracture resistances. After artificial aging, crack formation was observed in a high percentage for fully veneered crowns of all test groups, but only for one veneering ceramics with cutback crowns. Mean test forces of unaged crowns were F1d,mean ≥ 422 N | Fu,mean ≥ 749 N (fully veneered) and F1d,mean ≥ 644 N | Fu,mean ≥ 706 N (cutback) dropped significantly to F1d,mean ≥ 131 N | Fu,mean ≥ 223 N (fully veneered) and F1d,mean ≥ 324 N | Fu,mean ≥ 524 N (cutback) . Conclusions: Within the limitations of this laboratory study, 5Y-PSZ based anterior crowns can be a viable treatment option. Framework design, choice of the veneering ceramics and artificial aging show relevant effects on the fracture resistances. Concerted veneering ceramics should be used and partially veneering of the zirconia frameworks should be favored over full veneers.

Assessment of Dental Arch Symmetry Measurements on Conventional and Digital Study Model: A Validity, Reliability, and Reproducibility Study

Abstract Aim: This study aims to assess the validity, reliability, and reproducibility of dental arch symmetry measurements between conventional study models and digital study models. Materials and Methods: The study sample comprised 50 pretreatment diagnostic conventional study models. The symmetry of the dental arch is evaluated by using the perpendicular distance from the tips of the canine and the first molar distobuccal cusps to the dental arch center line. This line is drawn from the midpoint of the right and left incisor edges to perpendicularly intersect the line connected by the tips of the right and left second molar distobuccal cusps. The distances from the midpoint of the right and left incisor edges to the tips of the right and left second molar distobuccal cusps to evaluate the symmetry of the dental arch were also measured. Results: These results revealed that in measurement on conventional study models in the upper arch, the mean value of dental arch form at maxillary right second molar was 26.55, and dental arch form at maxillary left second molar was 26.53. Measurement on three-dimensional (3D) models in the upper arch, the mean value of dental arch form at the maxillary right second molar was 26.50, and dental arch form at the maxillary left second molar was 26.50. Measurement on plaster models in the lower arch the mean value of dental arch form at the mandibular right second molar was 24.48 and dental arch form at the mandibular left second molar was 24.42. Measurement on 3D models in lower arch the mean value of dental arch form at mandibular right second molar was 24.08 and dental arch form at mandibular left second molar was 24.08. Furthermore, there was no statistically significant difference in arch symmetry measurements between the conventional study model and the 3D digital model. Conclusion: This study concludes that dental arch symmetry measurements of digital study models were as valid, reliable, and reproducible compared with conventional study models.

Clinical evaluation of three different anterior reference points on protrusive condylar guidance angle using a semi adjustable articulator and lateral cephalogram

Background: Studies had shown that different anterior reference points can mount the maxillary cast in variable position in the articulator which may affect the protrusive condylar guidance angle on setting the semi adjustable articulator. So there is a need for search of reliable anterior reference point in orienting the maxillary cast on the articulation for accurate prosthesis fabrication. Aim: The aim of this study was to determine the effect of 3 different anterior reference points Orbitale, Orbitale minus 7mm, 36mm from the incisal edge of maxillary central or lateral incisor on the protrusive condylar guidance values registered on Hanau wide vue articulator and compare it to the protrusive condylar guidance angle obtained from lateral Cephalometric tracings. Materials and methods: A total of 30 healthy human subjects were randomly selected for this study from volunteer dental students. Orbitale, Orbitale minus 7mm, 36mm from the maxillary incisal edge of the subjects were the three anterior reference points used for facebow transfer using Hanau springbow. With the help of protrusive records, articulation was done in Hanau wide vue articulator using this record and condylar inclination values were noted on right side and left side.Three sets of lateral cephalometric radiographs were taken in maximum intercuspation and protrusive position, traced manually and values tabulated for all 30 subjects. Results: Mean value of orbitale is highest and mean value of 36mm from the maxillary incisal edge is lowest. Conclusion: Orbitale can be used as a reliable anterior reference point in facebow transfer using hanau wide vue articulator.

Effect of Increasing Occlusal Vertical Dimension on Smile Parameters

Introduction: Increasing Occlusal Vertical Dimension (OVD) becomes important aspect of complex prosthodontic treatment for maintaining balance between form of oral structures and function of stomatognathic system. The purpose of this study is to determine the effect of increasing OVD on various smile parameters during posed smile. Methodology: This observational descriptive study included 30 patients, 14 male and 16 females, visiting dental department of National Academy of Medical Sciences (NAMS), Bir Hospital. Four polyvinyl siloxane bite records were fabricated on stone cast mounted on a semi-adjustable articulator increasing OVD by +1 mm, +2 mm, +3 mm and +4 mm taking incisal pin as a reference. Photographs of posed smile were taken at OVD of +0 mm, +1 mm, +2 mm, +3 mm and +4 mm using a DSLR camera mounted on a tripod. Head position was stabilized using a head positioning device of a cephalometric unit during photography. Adobe photoshop CS6 extended was used to calculate the various measurement in pixel which was converted into mm with help of conversion ratio obtained. Data were then processed and analyzed using SPSS software at the 5 % significance level. Result: One-way repeated measures ANOVA found statistically significant differences in interlabial gap height, incisal edge to lower lip distance, smile index and display zone area with increasing OVD. No statistically significant differences were found for intercommisural width and incisal edge to upper lip distance. Conclusion: Within the limitations of this study, the excessive increase of OVD may lead to excessive interlabial gap height, incisal edge to lower lip distance, and display zone area. Also, the increase of OVD may lead to reduced smile index. No change may be expected in the position of the upper lip with increase of OVD. In addition, a change in the intercommisural width of the smile should not be expected with increasing OVD.

Effect of Age, Gender and Lip Length on Anterior Teeth Display

Aim: To evaluate the exposure of maxillary and mandibular teeth during lips at resting position and study the effect of age, gender and lip length on the anterior teeth display. Study design: Cross sectional observational study. Place and duration: Prosthodontic Department, Lahore Medical and Dental College from 5th June till 5th September 2022. Methodology: Selected subjects comfortably seated in dental chair. The resting position of upper lip length was recorded from subnasale to stomion at the facial midline. With participant at rest position; visible portion of anterior teeth were measured vertically from lower border of upper lip to incisal edge of incisors (canine tips at the mid-point) in maxillary teeth using vernier caliper. For mandibular teeth readings were taken from the lower lip upper border to the incisor’s edges of lower teeth (at the mid-point of canine cusp tip). Three readings of each tooth were recorded and mean value taken. Results: The visibility of anterior teeth was more prominently seen in females as compared to males but this finding was statistically insignificant. Decrease in the exposure of maxillary teeth and increase in the exposure of mandibular teeth was significantly found(p<0.05). More female participants were found with shorter lip lengthsas compared to males (p<0.05). Lip length association with increasing age was found to be significantly increased with increasing age. It was 8.99 ± SD 1.42 in age group less than 30 years, 9.02 ± SD1.57 in age group 31-50 and 10.01±SD 1.42 in participants above 50 years of age. Conclusion: There was no significant difference in exposure of anterior teeth at rest between gender. Females have shorter lip lengths than males. The upper lip length increases with increasing age. The exposure of maxillary anterior teeth significantly decreases and mandibular teeth increases with increasing age. Keywords: Anterior teeth, aging, gender, tooth display, tooth visibility, lip length.

Evaluation of Apical Root Resorption during Alignment Phase of Fixed Orthodontic Treatment: A Prospective Study

Purpose: External apical root resorption (EARR) is a permanent shortening of the root apex, often detected through radiographic imaging, characterized by the loss of the protective outer layer.To evaluate the apical root resorption during alignment phase of fixed orthodontic treatment Method: Prospective Study was conducted in the Department of Orthodontic, Nishtar Institute of Dentistry, and Multan from 6th October 2020 to 5th April 2021. The study included a 110 patients aged between 18 and 25 years. The evaluation of External Apical Root Resorption (EARR) was conducted prior to and following the therapy. In order to carry out this assessment, a group of 110 patients underwent periapical radiographs utilizing the paralleling approach. The radiographs were taken at the beginning of the treatment and then again at the conclusion of a three-month research period. Afterwards, the length from the incisal edge to the apex of all incisors was carefully measured using a vernier caliper. The difference in root length, measured in millimeters, between the pre-treatment (T0) and post-treatment (T1) stages was measured and expressed as a percentage of the initial root length.

Fenestration and Dehiscence in Human Maxillary Alveolar Bone: An In Silico Study Using the Finite Element Method.

Fenestration and dehiscence are alveolar bone defects. Although not considered a pathology, these alveolar bone defects end up influencing dental treatment, such as surgeries, mainly periodontal, and therefore must be considered during treatment planning. However, currently, little is known about the biomechanical origin of these bone formations. The aim of the study was to use the finite element method (FEM) to test hypotheses of predictive factors for fenestrations and dehiscence in human alveolar bone. A FEM simulation of the action of functional, parafunctional, and orthodontic occlusal loads on the upper central incisor and upper canine was performed. For the simulation, a three-dimensional model of an adult human skull, fully dented and with intact bone structure, was constructed from computed tomography images. The buccal alveolar bone lamina was evaluated considering the calculation of equivalent stresses, as well as maximum principal stresses. The action of functional and parafunctional forces on the incisal edges and the orthodontic force on the buccal face of the upper central incisor and upper canine teeth generated tensions at different levels of magnitude in the buccal bone lamina, varying in regions, at all levels of strength. Changing levels of force magnitude resulted in variations in relation to the level of deformation. The computational simulation using the FEM was able to identify a difference in stress in the alveolar bone tissue in each of the applied forces. The difference in stresses obtained may suggest the formation of dehiscence or fenestration in the region studied.

Measurement of distance between maxillary central incisors and incisive papilla in dentate individuals.

Objective: To measure the distance amongst the incisive papilla’s centre and posterior border to the incisal edge of the upper central incisors in dentate individuals.Methodology: This descriptive cross-sectional study was conducted at Department of Prosthodontics at Isra Dental Col-lege, Hyderabad from May, 2020 to Feb, 2021. During study period, 200 patients aged between 20-40 years of either gender were included. Impressions and casts made. On the cast and distance measured and recorded for maxillary central incisor and incisive papilla with the help of vernier calliper.Results: Mean distance between maxillary central incisive papilla’s centre was 9.20mm while it was 12.47mm from up-per incisor to the incisive papilla’s posterior border. Distance among the maxillary central incisor to the incisive papilla’s center and posterior border were significant statically in both genders.Conclusion: While fabricating removable prosthesis, the results of current study may used as primary point for position of maxillary incisors.
 Key words: Anatomical landmarks, Central incisors & Incisive papilla. Removeable prosthesis

Age and sex related change in tooth enamel thickness of maxillary incisors measured by cone beam computed tomography

BackgroundTo measure adequate enamel thickness of maxillary incisors in planning enamel reduction for a porcelain laminate veneer restoration in relation to chronological age and sex by using cone beam computed tomography (CBCT) in an Iraqi subpopulation.MethodsFrom 81 CBCT images, 324 maxillary incisors were examined. Enamel thickness was measured at both mesial and distal regions of the tooth in three different levels: cervical, middle, and incisal (occlusal) 1/3 at a sagittal section. Measurements were made for the following tooth areas using CBCT: facial enamel thickness at 1, 3, and 5 mm from the cementoenamel junction (CEJ), palatal enamel thickness at 5 mm from the CEJ (5 mm P), facial and palatal enamel thickness at the incisal edge (IFP), mid incisal enamel thickness (IET), and the incisal edge enamel-pulp distance (IEPD). Relationships of enamel thickness with age and sex were evaluated using Independent t-test, Mann–Whitney U-test and the Pearson correlation coefficient, a simple linear regression analysis used for statistical analysis.ResultsSignificant differences (P < 0.05) were found in terms of an inverse association between enamel thickness and chronological age at all measurements above the CEJ and the regression model for the mid-incisal enamel thickness was (R2 of 0.4). In contrast, there was an increase in IFP, palatal, and IPED enamel thickness with age. Also, significant differences were found in enamel thickness between males and females, the enamel being thicker in females in relation to facial enamel thickness, enamel palatal thickness above CEJ and IET, while for IEPD, the enamel thickness was greater in males compared to females.ConclusionThe measurements for enamel thickness outcome variables in relation to chronological age revealed significant differences for each measured distance and there were statistically significant differences in enamel thickness between males and females at all measurements except at IFP. These results demonstrate that CBCT can be used for noninvasive, accurate measurements of enamel thickness in both sex.

Digital workflow to produce 3D-printed incisal facial indirect restoration with lingual rest seats to support a removable partial denture

A technique for fabricating lingual rest seats and indirect incisal restorations using a digital workflow is described. After intraoral scanning, the incisal edge position of the restoration and lingual rest seats for a subsequent removable partial denture (RPD) were designed digitally. Adaptation was evaluated with trial restorations, and definitive restorations were printed from a 3-dimensional resin (Varseo Smile Crown Plus Bego; Wilcos). The restorations were cemented with a heated composite resin (Tetric N; Ivoclar AG) polymerized for 40 seconds. The RPD was fabricated and delivered following a conventional technique. This standard, rapid, cost-effective, and straightforward approach allows a controlled and standardized process to obtain lingual rest seats and incisal restorations simultaneously, providing support for a successful Kennedy Class I RPD.

VISTA approach in conjunction with enamel matrix derivative, cortico-cancellous bone, and connective tissue graft for periodontal defect surgery: A case series.

The biggest challenge during periodontal regeneration in the anterior region is the prevention of soft-tissue recession. Minimally invasive surgeries, particularly papilla preservation techniques and soft-tissue augmentation, may significantly reduce such postoperative soft-tissue recession. This article presents the vestibular incision subperiosteal tunnel access approach for periodontal regeneration in the anterior region. A subperiosteal tunnel prepared from a single vertical vestibular incision adjacent to the defect is used for debridement, enamel matrix derivative application, defect grafting with cortico-cancellous tuberosity bone, and insertion of the connective tissue graft. Evaluation of six cases with up to 6 years of follow-up showed improvements in all clinical parameters. The probing pocket depth improved from 8.2±0.75 mm initially to 2.7±0.52 mm at follow-up, clinical attachment level improved from 8.5±0.83 mm initially to 2.7±0.52 mm at follow-up, and midfacial gingival recession of 1 mm at two sites was corrected. The papillae were stable at all sites, with an average distance of 4.8 mm from the incisal edge to the papilla tip. This technique seems to be a promising approach for achieving both esthetic and functional goals of periodontal regenerative surgery. However, experience in performing microsurgeries and harvesting tuberosity tissues may be a limitation.

TO CORRELATE THE RELATIONSHIP OF THE DISTANCE BETWEEN LINGUAL FRENAL ATTACHMENT AND MANDIBULAR INCISAL EDGE POSITION AS AN AID IN ESTABLISHING MANDIBULAR OCCLUSAL PLANE: A CROSS-SECTIONAL SURVEY

Background: The determination of vertical dimension, aesthetics, phonetics and incisal guidance, depends on the placement of anterior teeth. Fewer studies are present for mandibular anterior teeth setting. Therefore this study aims at determining the correlation of distance between lingual frenal attachment and mandibular incisal edge position in dentulous subjects as an aid in establishing mandibular occlusal plane in edentulous patients. Methodology: 318 subjects (161 males and 157 females) under the age group of 18 to 30 years, who met the requisite criteria were seleceted. A mandibular cast was obtained from irreversible hydrocolloid impression in stock trays for each subject. The distance between the incisal edge of lower central incisor and anterior attachment of the lingual frenum was measured using digital vernier caliper. Result:It was observed that the distance between anterosuperior attachment of lingual frenumand mesioincisal edge of mandibular central incisor (CI) in female subjects was 12.19, with mean standard deviation (±SD) of 1.34. and 15.91 with mean standard deviation (±SD) 1.32 in male subjects respectively. Conclusion:Thus, the anterior attachment of lingual frenum is a reliable anatomic landmark and shall aid in setting the mandibular central incisors in a more natural position.

The Effect of Preparation Design on Stress Distribution in Lithium Disilicate Laminate Veneer using 3D Finite Element Analysis.

Background: A layer of ceramic bonded to the facial surfaces of prepared teeth to create a ceramic esthetic veneer, also known as a laminate veneer. Objective: This study aimed to examine the effect of preparation design on the stress distribution in lithium disilicate veneer at different angulations of masticatory loading. Methods: The finite element approach assessed the structure stress distribution. So, Exocad dental CAD was used to obtain the models, which consist of an upper central incisor in three dimensions (3D), and prepare them with the same software for an indirect veneer. The models were imported into software (SolidWorks; Dassault Systems) to construct solid models. The external load used in this study was 100 N at 60 degrees (intercuspal) and 125 degrees (protrusive) in the palatal surface, two mm below the incisal edge. The models were restored using e-max laminate veneers with different tooth preparation designs (palatal chamfer and window preparation designs). Analysis and calculations were performed on the stress distributions and maximum stress values of the tooth structures, cement layer, and laminate veneer. Results: With a window preparation design, the maximum stress values in the tooth and laminate veneer were higher. In the palatal chamfer design, stresses were dispersed more consistently through the cement layer and laminate veneer. Higher stress was generated by protrusive movement than by intercuspal movement. Conclusion: Compared to window preparation, the palatal chamfer design for lithium disilicate laminate veneer showed a more favourable stress distribution. Regardless of the preparation design, maximum stress values were observed in the cervical and incisor areas of the tooth structure.

The Effect of Preparation Design on Stress Distribution in Lithium Disilicate Laminate Veneer using 3D Finite Element Analysis.

Background: A layer of ceramic bonded to the facial surfaces of prepared teeth to create a ceramic esthetic veneer, also known as a laminate veneer. Objective: This study aimed to examine the effect of preparation design on the stress distribution in lithium disilicate veneer at different angulations of masticatory loading. Methods: The finite element approach assessed the structure stress distribution. So, Exocad dental CAD was used to obtain the models, which consist of an upper central incisor in three dimensions (3D), and prepare them with the same software for an indirect veneer. The models were imported into software (SolidWorks; Dassault Systems) to construct solid models. The external load used in this study was 100 N at 60 degrees (intercuspal) and 125 degrees (protrusive) in the palatal surface, two mm below the incisal edge. The models were restored using e-max laminate veneers with different tooth preparation designs (palatal chamfer and window preparation designs). Analysis and calculations were performed on the stress distributions and maximum stress values of the tooth structures, cement layer, and laminate veneer. Results: With a window preparation design, the maximum stress values in the tooth and laminate veneer were higher. In the palatal chamfer design, stresses were dispersed more consistently through the cement layer and laminate veneer. Higher stress was generated by protrusive movement than by intercuspal movement. Conclusion: Compared to window preparation, the palatal chamfer design for lithium disilicate laminate veneer showed a more favourable stress distribution. Regardless of the preparation design, maximum stress values were observed in the cervical and incisor areas of the tooth structure.

Increased Occlusal Vertical Dimension and Its Influence on Lip Position at Smile in Dentulous Adults

Introduction: Increasing occlusal vertical dimension (OVD) is often indicated in complex prosthodontic rehabilitations to gain restorative space and improve the occlusal relationship and esthetics. However, any alterations made in OVD will also influence the lip position mainly during rest and smile. This study aims to determine the influence of the vertical dimension of occlusion on lip positions at a smile. Methods: 30 samples between the age group of 20 - 30 years were included in this study meeting the selection criteria. The acrylic splint of varying thicknesses of +2mm, +4mm, +6mm, +8mm was prepared on the dental stone cast of a patient that was articulated in a semi-adjustable articulator after tentative facebow transfer. Smile photograph of each individual at the occlusal vertical dimension of +0mm, +2mm, +4mm, +6mm, +8mm was taken using a DSLR camera mounted on a tripod using the prepared acrylic splints. Digital measurements were done in photographs using the Adobe Photoshop software. Results: The study's results demonstrate that increasing the OVD significantly affects the inter labial distance, incisal edge to lower lip distance, and the display zone area. However, the study found no notable alterations in the distance from the incisal edge to the upper lip or in the intercommissural width with the same increased OVD. These findings demonstrate on how changes in OVD can influence various orofacial measurements. Conclusion: Within the limitation of this study, it can be concluded that with the increase in the OVD, inter labial distance, incisal edge to lower lip distance, and display zone area are increased. But upper lip position and inter commissural width should not be expected to be changed with increased OVD.

Assessment knowledge of dental erosion, signs and symptoms, and causes among adult in Saudi Arabia: A cross-sectional survey

Abstract Introduction: Dental erosion results from the chemical effect of nonbacteria origin. The causes of dental erosion could be from the intrinsic or extrinsic origin. Dental erosion is a silent disease as symptoms and signs occur gradually. Aims: To assess the knowledge of adults in Saudi Arabia about the causes, signs, symptoms, and factors that increase the possibility of getting dental erosion. Materials and Methods: A cross-sectional study was conducted using an online-based self-administrated questionnaire. The sampling was convenient with a snowball effect. It was divided into four sections; demographic data, signs, and symptoms, causes, and factors that increase acidic effect. Results and Discussion: A total of 765 respondents completed the online survey. Looking at dental erosion signs and symptoms, 57% identified chipping of the incisal edge of the teeth, and 47.6% increased teeth translucency. Asking the participants about causes of dental erosion 59% identified soft drinks and citrus fruit, followed by 44% putting lemon near the teeth for a long time. Eighty-three percent of the participants recorded visiting the dentist when noticing signs or symptoms of dental erosion. The responses highlighted dental students had higher level of knowledge compared to other. Conclusion: Increasing public awareness of dental erosion is important, as only a third of all participants were able to identify three or more dental erosion signs and symptoms, and 10% identified 5 out of 8 dental erosion causes. Participants with dental backgrounds showed the highest percentage of identifying dental erosion causes and, signs and symptoms, however, it is still low. Therefore, improving dental erosion learning outcomes should be improved in our colleges.

ASSESSMENT OF ESTHETIC SMILE COMPONENTS BY DENTAL STUDENTS

Background: The present information indicates that most students utilized the technology-based system well, but they missed some practical activities. Assessment of students’ satisfaction with the e-learning activities and asking for feedback can help institutions to improve the know-how about e-learning practices. Hopefully, the sudden pandemic-related shift through modes of education will not be considered an unfavorable impact on education but an evolving experience to pave a comprehensive way to technology-based educational activities.Material and methods: The study was performed on 580 dental students. Among the eight components of the balanced smile, six factors (the smile arc, smile line, dark buccal corridors, gingival margin and incisal edge asymmetries, tooth axis, and dental midline inclinations) apart from those related to dental and gingival ones, were examined on photographs. Manipulations were made on the photo of a female patient with the ideal smile.Results: Statistically significant differences were observed between the preclinical and clinical groups and, in binary comparisons, between curricular years at pre-clinical and clinical levels (P &lt; 0.05).Conclusions: Our findings confirm the reports from previous investigations considering the impact of dental education on dental students’ perception of dentofacial esthetics.

Comparative analysis of the biomechanical behavior of the maxillary central incisors restored with glass fiber post and cast metal post and core submitted to orthodontic forces: A study with finite elements

Different types of intraradicular restorations and their insertion have an impact on teeth biomechanics. This study aimed to analyze the biomechanical behavior of maxillary central incisors restored with glass fiber post (GFP) and cast metal post and core (CMP) subjected to buccolingual and mesiodistal orthodontic forces using the finite element method. Two models of the maxillary central incisor with periodontal ligament, cortical bone, and trabecular bone were made. One of the models included intraradicular restoration with GFP, whereas, in the other, the incisor was restored with CMP. After creating the tridimensional mesh of finite elements, applying 2 orthodontic forces were simulated: 65 g of buccolingual force and 70 g of mesiodistal force. The forces were applied parallel to the palatal plane in the region of the bracket slot, located 4 mm to the incisal edge. The maximum stresses generated in the GFP-restored root were 3.642 × 10-1 MPa and 4.755 × 10-1 MPa from the buccolingual and mesiodistal forces, respectively. Likewise, the stresses in the CMP restored root were 2.777 × 10-1MPa and 3.826 × 10-1MPa. The radicular area with higher stress on both models was located in the cervical third: on the buccal surface when the buccolingual force was applied and on the mesial surface when the mesiodistal force was applied. The highest stress levels were found on the CMP structure. The incisor restored with cast metal post revealed lower stress values transferred to the root than the one restored with GFP. The stresses on the structure of the GFP were lower and more homogeneous than the ones found on the cast metal post. The difference among the stress values in the materials is within a safe margin for using both materials in relation to orthodontic forces.

Shade selection for natural tooth color replication on porcelain laminate veneers

The final color of dental ceramics depends on different factors such as light source, substrate, and selected material (thickness, contour, and texture). Objective: To report a clinical case in which a predictable protocol is used to optimize the final color of porcelain laminate veneers. Case report: A male patient attended the dental clinic dissatisfied with the composite resin restorations made on his upper anterior teeth. After anamnesis and clinical examination, it was suggested that the resin restorations be replaced by laminated porcelain veneers. A diagnostic wax-up was performed. The mock[1]up was also used to evaluate the aesthetic length for replicating the details of the incisal edge and the shape and size of the embrasures. The shade was selected before composite resin removal to avoid dehydration of the dental substrate. A photograph was taken to guide the selection of colors in different thirds. After removing the restorations, another photograph was taken to evaluate the color of the substrate. The impression was taken with 000 retractor wire and addition silicone. The laminates were made with pressed ceramic and feldspathic porcelain veneers were subsequently applied by layering the layers of dentin, incisal edge and enamel based on the waxing diagnosis. After approval by the patient, a conventional cementation technique was performed. The occlusal adjustment was made with rubber polishing cups and the anterior and lateral guides were checked. Conclusion: The protocol recommended for successful selection of the color of a porcelain laminate relies on the combination of knowledge of concepts, resources such as shade guides, spectrophotometers, and photographs, and porcelain application and characterization techniques performed by the technician and luting techniques by the dentist.