Anterior Restorations Research Articles

The ability of mouthguards to protect veneered teeth: A 3D finite element analysis.

Professional and amateur athletes might have veneer restorations. The aim of this study was to investigate the protective effect of mouthguards on veneered anterior restorations. A nonlinear dynamic analysis was performed to simulate conditions during an impact with or without a custom-made mouthguard. Using a computer-aided design (CAD) software, a slice of a human maxilla was designed containing an upper right central incisor. The model was composed of mucosa, cortical bone, trabecular bone, periodontal ligament, dentin, enamel, and pulp tissue. The enamel was prepared (feather design), restored with an indirect veneer (1.0 mm thickness), and duplicated to simulate both conditions with or without a mouthguard (4 mm thickness). Both models were subdivided into finite elements using the computer-aided engineering (CAE) software. Frictionless contacts were used, and an impact was simulated in which a rigid sphere hit the model at 1m s-1 . Fixation was defined at the base of the bone. The elastic modulus of the veneer was assessed by using five different restorative materials (resin composite, hybrid ceramic, zirconia-reinforced lithium silicate, lithium disilicate, and zirconia). Von Mises stress, minimal principal stress, and maximum principal stress (in MPa) were obtained and plotted for visual comparison. Von-Mises results showed higher stress concentrations in the veneer's cervical labial region for models without a mouthguard. Observing the quantitative results for each model, the highest compressive (709 MPa) and tensile (58 MPa) stresses occurred in the situation without a mouthguard with a zirconia veneer, while the lowest occurred in resin composite veneer with a mouthguard (8 and 5MPa). The mouthguard was able to reduce the stresses in the tooth structure and it also reduced the risk of fracture in all conditions. Mouthguards were beneficial in reducing the effects of dental trauma regardless of the restorative material used to manufacture the indirect veneer, since they act by dampening the generated stresses during the trauma event. Equal impact stresses on a mouthguard will lead to higher stresses in veneered teeth with more rigid restorative materials leading to a less protective effect.

Evaluation of direct restorations using the revised FDI criteria: results from a reliability study

ObjectivesThe purpose of this in vitro reliability study was to determine the intra- and inter-examiner agreement of the revised FDI criteria including the categories “fracture of material and retention” (F1) and “caries at restoration margin” (B1).Materials and methodsForty-nine photographs of direct tooth-coloured posterior (n = 25) and anterior (n = 24) restorations with common deficiencies were included. Ten dental experts repeated the assessment in three blinded rounds. Later, the experts re-evaluated together all photographs and agreed on a reference standard. Statistical analysis included the calculation of Cohen’s (Cκ), Fleiss’ (Fκ), and weighted Kappa (wκ), the development of a logistic regression with a backward elimination model and Bland/Altman plots.ResultsIntra- and inter-examiner reliability exhibited mostly moderate to substantial Cκ, Fκ, and wκ values for posterior restorations (e.g. Intra: F1 Cκ = 0.57, wκ = 0.74; B1 Cκ = 0.57, wκ = 0.73/Inter F1 Fκ = 0.32, wκ = 0.53; B1 Fκ = 0.41, wκ = 0.64) and anterior restorations (e.g. Intra F1 Cκ = 0.63, wκ = 0.76; B1 Cκ = 0.48, wκ = 0.68/Inter F1 Fκ = 0.42, wκ = 0.57; B1 Fκ = 0.40, wκ = 0.51). Logistic regression analyses revealed significant differences between the evaluation rounds, examiners, categories, and tooth type. Both the intra- and inter-examiner reliability increased along with the evaluation rounds. The overall agreement was higher for anterior restorations compared to posterior restorations.ConclusionsThe overall reliability of the revised FDI criteria set was found to be moderate to substantial.Clinical relevanceIf properly trained, the revised FDI criteria set are a valid tool to evaluate direct and indirect restorations in a standardized way. However, training and calibration are needed to ensure reliable application.

Color stability and surface roughness of ormocer- versus methacrylate-based single shade composite in anterior restoration

BackgroundThe blending ability of universal shade composites and their stability in the oral environment are of great concern in restoring anterior teeth. This study aims to evaluate and compare the color stability and surface roughness of two single-shade composite restorations, ormocer-based composite (OBC) and methacrylate resin-based composite (RBC), after storing them in different staining media.Materials and methodsIn this study, two universal shade composite restorative materials were tested: a nanohybrid OBC (Admira fusion X-tra, Voco) and a supra-nanofilled RBC (Omnichroma, Toukyama). In total, 60 cylindrical centralized cavities (diameter: 5 mm, depth: 2 mm) were prepared in sound extracted-human central incisors and divided into two equal groups according to the restorative material used (n = 30). According to the storage media, the teeth of each group were divided into three subgroups (n = 10): artificial saliva, black tea, and cola. The restoration color was evaluated for all teeth at baseline and after four weeks of storage. The color stability (∆E) was measured using a reflective spectrophotometer (X-Rite, model RM200QC, Neu-Isenburg, Germany). The surface roughness (Ra) was evaluated using three-dimensional optical profilometry (Wyko, Model NT 1100, Veeco, Tucson, USA). Additionally, the extracted data were analyzed using two-way analysis of variance (ANOVA), one-way ANOVA and Student’s t-test.ResultsIn the baseline evaluation, there were no statistically significant differences with respect to color matching or surface roughness results between the two studied restorative materials. However, the differences were statistically significant after storing them in different media.ConclusionUniversal composites showed satisfactory color matching with different teeth colors and accepted surface smoothness, whereas the aging procedure exerted a negative effect on their color stability and surface characteristics.

The Impact of the COVID-19 Pandemic and Vaccination on Dental Restorative Practices in the Geriatric Population

Objective: Vaccines were considered as one of the most important public health measures during the coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to quantify and compare restorative dental practices of geriatric patients during pre-pandemic, prevaccination, and post-vaccination periods. Materials and Methods: Dental records of patients aged older than 65 who presented to Bursa Oral and Dental Health Training and Research Hospital were included in the study. Restorative dental practices during the three periods: pre-pandemic period (01.01.2019−10.03.2020), pre-vaccination period (11.03.2020−13.02.2021) and post-vaccination period (14.02.2021−01.09.2021) were reviewed according to the patient’s age (young-old, middle-old and old-old), sex, tooth number (anterior and posterior), restoration type (occlusal, proximal, or cervical) and the type of restoration material (amalgam or composite). Results: Anterior restorations accounted for more than half (53%) of all restorations in the pre-COVID-19 pandemic period and 46.5% and 55.4% of restorations in the pre- and post-vaccination periods, respectively. The distribution of posterior amalgam restorations in the pre-pandemic period (31.5%) was higher than the pandemic period; in contrast, the composite restorations were higher during the pandemic pre-vaccination (73.9%) and post-vaccination (76.3%) periods (p<0.001). The males (odds ratio (OR): 1.17, 95% CI: 1.03-1.34, p=0.02) and middle-old (OR: 0.79, 95% CI: 0.64-0.96, p=0.019) were more likely to use restorative dental services as compared to females and youngold age, respectively. Conclusion: Vaccination had a noticeable effect on increased admissions of geriatric patients and restorative dental treatments compared to the pre-vaccination period. In addition, in the post-COVID-19 vaccination period, composite restorations seem to have replaced amalgam restorations.

Restoration of vertebral body height in traumatic thoracolumbar fractures: open versus minimal invasive surgery – which is better?

Background Percutaneous minimally invasive surgery (MIS) has been increasingly implemented to treat thoracolumbar (TL) fracture against a conventional open pedicle screw fixation (OPSF) with desirable radiological and clinical outcomes. Studies in the Indian context are required to determine the efficiency of MIS over OPSF. Objective To compare restoration and maintenance of vertebral body height (VBH) following MIS versus OPSF. Methods A prospective comparative study was conducted in a tertiary care hospital. Patients (n= 36) aged 18–65 years (males = 23, females = 13) with traumatic TL fractures were identified. Eighteen of them underwent OPSF and other eighteen underwent MIS. The radiological outcomes like anterior and posterior vertebral body height percentage (AVBH % and PVBH %) restoration and maintenance were evaluated. Quantitative variables were analyzed and described using mean ± standard deviation and qualitative variables were presented using frequency and percentage. Student t-test was used to analyse continuous data and Chi-square/Fisher Exact test was used to analyse categorical data. Results The mean age of the patients was 38.8 years. The majority of fractures were seen in the T12-LI segment (52.7 %). The AVBH % restoration and maintenance in OPSF was significantly higher compared to that of MIS at immediate post-operative (IPO) period (p = 0.01), 6 weeks (p = 0.02) and 12 weeks (p = 0.006) post-surgery. Long segment stabilization provided statistically significant AVBH and PVBH values for OPSF compared to MIS (p < 0.05). The presence or absence of pedicle screw at fractured vertebral level did not restore AVBH and PVBH to a statistically significant level in both the groups (p > 0.05). Superficial surgical site infection (SSSI) was seen in both the groups without any statistical significance between them (p > 0.05). Conclusion OPSF is superior over MIS in the restoration of AVBH. Restoration of PVBH was also better with OPSF although not statistically significant. OPSF with longer segment fixation had better restoration of both AVBH and PVBH. The presence or absence of pedicle screw at fractured vertebral level did not seem to have any significance in both the groups. However, the MIS approach can be a reasonable alternative to open surgery with potential advantages like better clinical and functional outcome. A selected population of patients treated with MIS will show better surgical outcomes.

Digital workflow for a direct restorative procedure using a 4D virtual articulator

The purpose of this case report was to describe a procedure for 4D virtual mounting and how to develope static and dynamic occlusion through diagnostic waxing. A 16-years-old male patient with a recent history of anterior dental trauma presented with the complaint of esthetic and function restoration. The anterior guidance within the occlusal scheme in all anterior restoration should be considered as a relevant aspect as well as esthetics. A fully digital protocol was presented using a virtual articulator through the incorporation of data from 4D optical technology. The restorative therapy was carried out in the following phases: direct digital data collection acquisition, diagnostic waxing on a virtual model, and definitive restoration. The first step was the intraoral scan of both arches before treatment. The static interocclusal record was made in maximal intercuspal position by an Intraoral scanner and the dynamic one by new measuring system “Jaw Motion Analyser Optic System” (JmA (optic System/JMA; Zebris medical, Isny Germany), which aims at a complete digital workflow for the analysis of the occlusal scheme of mutually protected articulation. The 4D concept added a missing link, brought the digital workflow, and introduced patient-specific movements with kinematic digital facebow functionality. Esthetic and function digital waxing was made (Exocad GmbH) and a waxing cast was fabricated by 3D printing in addition a silicone index was produced from it. The direct composite restoration was made intraorally. This study seems to encourage furthermore clinical trials to validate the use of this methodology.

Clinical Performance of Direct Composite Restorations in Patients with Amelogenesis Imperfecta - Anterior Restorations.

To evaluate the clinical performance of direct composite restorations using nanohybrid and nanofill composite materials in anterior teeth in patients with amelogenesis imperfecta (AI). The study included 15 patients with AI aged 14-30 years. During the study, the patients received anterior direct composite laminate veneer restorations using either a nanohybrid (Clearfil Majesty ES-2 and Clearfil Universal Bond, Kuraray Noritake) or a nanofill resin composite (Filtek Ultimate Universal Restorative and Single Bond Universal Adhesive, 3M Oral Care). The restorations were evaluated according to the modified USPHS criteria at baseline and at 1-, 2-, 3- and 4-year follow-up periods. The cumulative success rate of anterior restorations was 80.5% for nanohybrid and 92.5% for nanofill composite after 4 years. Eight restorations with nanohybrid and three restorations with nanofill resin composites failed. Ten restorations failed due to fracture; the fracture rate was 12.3%. Statistically significant differences were found between nanohybrid and nanofill composites regarding marginal discoloration and surface texture after 3 years. Furthermore, statistically significant differences were observed with respect to color match after 4 years. The use of a nanohybrid or nanofill composite for anterior direct restorations in patients with AI was observed to be satisfactory, based on the rate of ideal and clinically acceptable restorations. The primary reason for restoration failure was fracture. The failure rate of nanohybrid composite restorations was higher than with nanofill composite restorations with respect to survival and marginal adaptation criteria.

The Ability of Two Chewing Simulation Devices in Emulating the Clinical Deterioration of Anterior Composite Restorations in Severely Worn Teeth.

This study investigated the ability of two chewing simulation devices to emulate in vitro the clinical deterioration observed in anterior composite restorations in severe tooth-wear patients. Advanced tooth wear was simulated in bovine incisors, which were restored with palatal and buccal direct composite veneer restorations. The incisal edges of restorations were subjected to 960K cycles of either compressive loading (Biocycle-V2; 125 N at 2 Hz) or wear and mechanical loading (Rub and Roll; 30 N at 20 rpm). Surface degradation was rated using FDI scores to compare the chewing devices (Fisher's test, a = 0.05). Topography and deterioration of restorations was analyzed using SEM. The ability to emulate the deterioration was investigated by comparing the surface degradation observed in vitro with the clinical degradation observed in restorations placed in severe tooth-wear patients after 3.5 years. Distinct degradation patterns were observed between the simulation devices: Biocycle-V2 generated deterioration that was not comparable to the clinical situation, including contact damage, minor wear, and localized roughening. The degradation caused by Rub and Roll was more similar to the in vivo situation, including wear facets, chipping, delamination, staining, and marginal ditching. The FDI scores were different between the chewing devices for surface/marginal staining, material/retention, and marginal adaptation (p = 0.003). SEM analysis showed microcracking at the interface between composite layers at the incisal edges. The Rub and Roll chewing device was able to emulate the clinical deterioration observed in anterior restorations in severe tooth-wear patients and thus may be used as an oral-cavity simulation method, contributing to translational research.

Aesthetic and functional rehabilitation in a patient with anterior skeletal open bite using lithium dissilicate glass-reinforced ceramic: a case report

The aim of this clinical report is to present the replacement of unsatisfactory metal-ceramic crowns of elements 12, 11, 21 and 22, by lithium disilicate glass-reinforced ceramic crowns in a patient with skeletal anterior open bite. A patient sought care at the Dental Hospital at the School of Dentistry of UFU, complaining of odor between the metal-ceramic crowns of the antero-superior teeth. After clinical and radiographic examination, invasion of the biological space was noticed, surgery was indicated in order to restore the biological space. After healing, the pre-existing cast metal posts were masked using an opaque composite resin and the teeth were reprepared for full all-ceramic crowns. Impressions were taken in two steps, using PVS associated to retraction cords. The ceramic copings were obtained in lithium disilicate ceramic, and the veneering was performed by stratification. After testing the ceramics crowns in relation to, fit, function and aesthetic results, cementation was completed using modified absolute isolation, followed by prophylaxis of preparations with pumice and saline, surface treatment of the ceramic restorations and luting using self-adhesive resin cement. Finally, an occlusal splint was produced to control the effects of bruxism and orofacial pain symptoms. The anterior open skeletal bite was a challenging factor for the rehabilitation of this patient; however, one must consider the entire process that the patient would undergo if choosing for orthognathic surgery, and the patient should be aware of the case limitations. In addition, the use of lithium disilicate glass-reinforced ceramics proved the versatility of this material for anterior aesthetic restorations.

Effect of Ageing, Staining and Polishing on the Colour Stability of a Single, a Group Shade and Nano Fill Dental Composite: An In-vitro Study

Introduction: With the increase in aesthetic requirements, more people are requesting tooth coloured fillings. An anterior restoration is deemed unacceptable if its color changes significantly. Aim: To assess the colour stability of a single shade, a group shade and a nano fill dental resin composite which comes in multiple shades. Materials and Methods: This in-vitro study was conducted in the month of August 2021 at the Advanced Technology Dental Research Laboratory at the King Abdul Aziz University, Jeddah,Western region, Saudi Arabia. Three composites were tested; a single shade (Omnichroma), a group shade (Optishade light (OL) and Optishade Medium (OM)) and a conventional nano fill (Z350) 40 cylindrical discs (10 mm in diameter and 2 mm in depth) were fabricated in total. Each material and shade to be tested had 10 samples per group (n=10). The materials were aged in a thermocycler for 5000 cycles then stained with either green tea or coffee for six days. Upon completion of the staining protocol, they were then polished with soflex diamond polishing system. Colour measurements were taken at each stage, calculated and compared. Mixed model repeated Analysis Of Variance (ANOVA) was performed to determine significance of the color change (ΔE00) between materials and treatments and Bonferroni test was used for multiple comparison between groups. Results: The effect of ageing varied according to individual material; Z350 had lower ΔE00 when compared to other materials. After staining with tea, it was found that Z350 and Omnichroma exhibited a significant change (p<0.05) in ΔE00 when compared to OL. Polishing improved the ΔE00 in all the materials. All green tea-stained materials with the exception of omnichroma returned to a clinically acceptable E00 after polishing. After polishing coffee stained samples, OL and OM remained above the clinically acceptable threshold while Z350 and omnichroma were returned to a clinically acceptable level. Conclusion: All the materials showed a change in ΔE00 after ageing, with OM and Z350 being the only materials to exhibit a clinically acceptable change. While polishing decreased ΔE00 in all the materials, it did not return them all to a clinically acceptable level. Thus, polishing helps improve the appearance of stained restorations but may not be enough to completely remove stains, even in newly introduced direct aesthetic dental materials.

P6 - Deterioration of composite restorations in tooth wear patients: translational approach

This study investigated the clinical deterioration of anterior resin composite restorations placed in tooth wear patients after 36 months and later compared the ability of two chewing simulation devices in emulating in vitro the clinical deterioration observed in those restorations. For the clinical observation, 270 anterior maxillary resin composite restorations in 47 patients were evaluated after 36 months of clinical service by using intraoral photographs and 3D scans to rate modified FDI scores and investigate the presence of degradation features. Multivariable logistic regression models were used to analyze the clinical data (p<0.05). For the in vitro approach, tooth wear was simulated in bovine incisors, which were restored with materials and techniques similar to those in the clinical observation. Incisal edges of the restorations were subjected to 960,000 cycles of either compressive loading (Biocycle-V2; 125 N; 2 Hz) or wear and mechanical loading (Rub&Roll; 30 N; 20 rpm). Surface degradation was rated using the modified FDI scores to compare the chewing devices (Fisher’s test, ?=0.05). In the clinical observation, early degradation signs were present at 1 month: irregularities (41.5%) and ditching (7.4%) were observed at the surface and adhesive interfaces. The frequency of irregularities decreased in the 36-month follow up (37%), but ditching (12.2%) and fractures (10.7%) were more common. After 36 months, the most frequent esthetic deterioration was noticeable for staining (44%) and loss of luster (31%). For functional deterioration, in the 3D scans, wear (25%), marginal adaptation (24%), and surface irregularities (19%) were the most frequent forms. The simulation devices produced distinct degradation patterns: Biocycle-V2 generated deterioration not comparable to the clinical situation, including contact damage, minor wear, and localized roughening. The degradation caused by Rub&Roll was more similar to the in vivo situation, including wear facets, chipping, delamination, staining, and marginal ditching. The FDI scores differed between the chewing devices for staining, material/retention, and marginal adaptation (p?0.003). The clinical observation revealed a continuous deterioration process in tooth wear patients with a progression of the deterioration until 36 months. The laboratory simulation of the deterioration showed that the Rub&Roll chewing device could emulate the clinical deterioration observed in anterior restorations in tooth wear patients and could be used as a mouth simulation method, contributing to translational research.

Evaluation of temporomandibular joint dysfunction by a mandibular tracing system: A case report

Objective: The purpose of this case report was to present a digital mandibular tracing technique that is used to evaluate a patient with temporomandibular joint dysfunction (TMD). Clinical features: A 65-year-old Caucasian female patient presented with chronic jaw pain in her temporomandibular joint (TMJ) area. The patient describes a dental history of orthodontic and prosthodontic treatment. Orally patient exhibits super erupted teeth, multiply fractured restorations, facial gingival recession, and rotated teeth. The patient also had an uneven occlusal plane and non-working side contact at maxillary first and mandibular second molars. Evaluation and outcome: A digital mandibular tracing technique, cone beam computed tomography, and full-arch optical impressions were used to evaluate the patient’s condition. The left condyle was slightly flat compared with the right one on the anterior surface. Limited protrusion and lateral movements and asymmetric border movements were detected. Apparently, an incomplete orthodontic treatment at the patient’s early age, iatrogenic mandibular anterior restorations, and hit and slight effect are considered causes of temporomandibular joint problems. The recommended treatment plan sequence for this patient is an occlusal adjustment, replacement of defective restorations, and fabrication of an occlusal guard for one of the arches. Conclusion: A digital mandibular tracing system can help the dentist to diagnose and analyze the causes of TMD patients specifically and individually. It also provides quick resolution and management for patients with TMD.

Evaluation of Temporomandibular Joint Dysfunction by a Mandibular Tracing System: A Case Report

Objective. The purpose of this case report was to present a digital mandibular tracing technique that is used to evaluate a patient with temporomandibular joint dysfunction (TMD). Clinicalfeatures.A65-year-oldCaucasianfemalepatientpresentedwithchronicjawpaininhertemporomandibularjoint(TMJ)area.Thepatientdescribesadentalhistoryoforthodonticandprosthodontictreatment.Orallypatient exhibitssupereruptedteeth,multiplyfracturedrestorations,facialgingivalrecession,androtatedteeth.Thepatient also had an uneven occlusal plane and non-working side contact at maxillary first and mandibular second molars. Evaluation and outcome. A digital mandibular tracing technique, cone beam computed tomography, and full-arch optical impressions were used to evaluate the patient’s condition. The left condyle was slightly flat compared with the right one on the anterior surface. Limited protrusion and lateral movements and asymmetric border movements were detected. Apparently, an incomplete orthodontic treatment at the patient’s early age, iatrogenic mandibular anterior restorations, and hit and slight effect are considered causes of temporomandibular joint problems. The recommended treatment plan sequence for this patient is an occlusal adjustment, replacement of defective restorations, and fabrication of an occlusal guard for one of the arches. Conclusion. A digital mandibular tracing system can help the dentist to diagnose and analyze the causes of TMD patients specifically and individually. It also provides quick resolution and management for patients with TMD.

Fatigue resistance of anterior monolithic crowns produced from CAD-CAM materials: An in vitro study

Statement of problemLithium disilicate and 5 mol% yttria partially stabilized zirconia (5Y-PSZ) are commonly used for anterior restorations. However, studies comparing the durability of 5Y-PSZ and lithium disilicates are sparse. PurposeThe purpose of this in vitro study was to investigate the fracture load of anterior monolithic crowns made of 2 lithium disilicates and a 5Y-PSZ under dynamic loading. Material and methodsTitanium abutments of the maxillary incisors were prepared (N=48, 8 for each group). Monolithic anterior crowns were made from the lithium disilicates (e.max CAD, Rosetta SM) and 5Y-PSZ (Katana UTML). After cementation, the specimens were stored in water for 24 hours and then thermocycled 10 000 times. Dynamic loading (70 N, 200 000 cycles, 1 Hz) was applied to half the specimens. The fracture load was measured by using a universal testing machine. The fracture patterns were analyzed and fractography applied. Two-way ANOVA and the Fisher exact test were used for statistical analysis (α=.05). ResultsThe material and dynamic loading affected the fracture load of the anterior monolithic crowns (P<.05). However, there was no interaction between the material and the dynamic loading (P=.079). Both lithium disilicates had higher fracture loads than 5Y-PSZ (P<.05). The fracture load of each specimen was reduced after dynamic loading (P<.05). Lithium disilicate showed marginal and bulk fractures, and 5Y-PSZ presented catastrophic fractures (P<.001). Conclusions5Y-PSZ materials with large grains and low flexural strength may be less resistant to fractures under dynamic loading than lithium disilicates.

Bilayered ceramic anterior restorations with reinforcement of the incisal edge by using lithium disilicate: A multicenter retrospective survival analysis with a maximum of 6-year follow-up

Statement of problemThe esthetics of anterior lithium disilicate restorations can be enhanced if the buccal aspect is layered with a feldspathic ceramic. However, whether fractures and chipping of this layer are a prevalent complication is unclear. PurposeThe purpose of this retrospective study was to evaluate the incidence of incisal fracture of a specially designed lithium disilicate reinforcement of the incisal edge for indirect anterior bilayered restorations on both teeth and implants. Material and methodsA total of 924 anterior bilayered pressed lithium disilicate restorations in 324 patients and made in one dental laboratory were delivered by 4 restorative dentists. The restorations had the palatal side of the incisal edge in monolithic lithium disilicate and the facial side in feldspathic porcelain. The restorations were evaluated for survival and the occurrence of fracture or chipping. Survival analyses were performed by using the Kaplan-Meier and log rank (Mantel-Cox) tests (α=.05). ResultsOf the 924 restorations, 798 (236 complete crowns, 562 partial restorations) were placed on teeth and 126 on implants. The mean observation time was 38 months (3 to 72 months). The survival rate was 96.5%, with 14 failures occurring. The failures were fracture after dental trauma (n=5), ceramic fracture (n=1), debonding (n=6), poor shade match (n=1), and tooth loss (n=2). Restorations in patients with parafunctional habits and endodontically treated teeth showed a significant decrease in survival rate (P=.018). No significant differences were found between the survival of restorations on teeth and implants and between complete crowns and partial restorations (P=.021). No chipping was observed on any restorations in the study. ConclusionsModified anterior bilayered ceramic restorations showed good survival rates, and no chipping was observed up to 6 years of follow-up. Parafunctional habits and endodontic treatment had a negative effect on the survival rate of restorations. The support of tooth or implant and the restoration type had no effect on the survival.

Efficacy and tooth sensitivity of at-home bleaching in patients with esthetic restorations: a randomized clinical trial.

This study aims to evaluate the color change and tooth sensitivity (TS) caused by at-home bleaching in patients with sound and with restored teeth. Forty patients were selected according to the inclusion and exclusion criteria and divided into two groups: So (patients with six caries-free maxillary anterior teeth) and Re (patients with at least one restoration in the six maxillary anterior teeth). Both groups were bleached with 10% carbamide peroxide (CP) at-home bleaching. The color change (CIELab [ΔE*ab], CIEDE00 [ΔE00], and whiteness index [∆WID]) were assessed using a spectrophotometer at baseline, 2weeks, and 1 and 3months after bleaching. Patients recorded their TS using a numeric rating scale (0-4). Data of color change were submitted to Student's T-test. The absolute risk and intensity of TS were compared using Fisher's and the Mann-Whitney tests, respectively (α = 0.05). Higher ΔE*ab, ΔE00, and ∆WID values were observed for So in relation to Re after all recall rate (p < 0.0001). No significant differences were observed regarding of bleaching-induced TS (p > 0.9). At-home dental bleaching with 10% CP generated the same pattern of TS in patients with or without restorations. However, in patients with restored teeth, it produced a lower color change after 2weeks of bleaching. After 2weeks of at-home bleaching, a lower whitening effect was observed in patients with anterior restorations when compared with patients with sound teeth. ClinicalTrials.gov identifier RBR-52j6gmg.

Clinical performance of direct composite resin restorations in a full mouth rehabilitation for patients with severe tooth wear: 5.5-year results.

ObjectivesTo evaluate the 5.5-year performance of direct resin composite restorations, prescribed for patients with severe tooth wear, requiring full-mouth rehabilitation. MethodsA convenience sample of 34 patients were recruited to a prospective trial between December 2010 and June 2013. The participants were provided 1269 full-mouth direct resin composite restorations (Clearfil AP-X) by 5 experienced operators, using the DSO-technique. Treatment resulted in an increase in the vertical dimension of occlusion (VDO). Failure was assessed at three levels. Frequencies of failure were analysed using Kaplan Meier survival curves and the effects of the relevant variables calculated with a multifactorial Cox regression (p < 0.05). ResultsAnnual failure rates (for all levels of failure, ‘Level 3- ‘) of ≤ 2.2% and ≤ 2.9% were respectively reported for the anterior and posterior restorations with a mean observation time of 62.4 months. The completion of an anterior restoration with the need for further appointments resulted in significantly more Level 2- & 3- failures. An evaluation of the performance of the premolar and posterior maxillary restorations showed significantly lowered risks of certain types of failures, compared to the molar and posterior mandibular restorations. ConclusionsAt 5.5 years, 2.3% of the overall restorations displayed catastrophic, (Level 1) failures. Molar restorations, posterior mandibular restorations and the anterior restorations requiring two further sessions for completion, were associated with significantly higher risks for failure. Clinical significanceDirect resin composite can offer an acceptable medium-term option for the treatment of severe, generalized tooth wear; molar restorations may require higher maintenance.

Does build angle have an influence on surface roughness of anterior 3D-printed restorations? An in-vitro study.

To evaluate the effect of build direction on the surface roughness (Ra) of stereolithography (SLA) printed full-coverage anterior dental restorations before and after surface polishing. A total of 45 full-coverage dental restorations were 3D printed using the SLA additive manufacturing technique. Five groups were defined based on the build angles: 90, 120, 135, 150, and 180 degrees. The Ra was measured with the contact profilometer to evaluate the arithmetic average of the absolute Ra value on the labial surface before and after polishing procedures. Data were analyzed using two-way ANOVA, and statistical significance was set at α = .05. The highest Ra was recorded in specimens printed with the 90-degree build angle, whereas the lowest values were recorded in specimens printed with the 180-degree build angle (P = .000). In all groups, the Ra values measured after polishing were significantly lower than prepolished values (P = .000), with no difference among the different build angles. Build angle significantly influenced the Ra of the SLA-printed full-coverage restorations. Polishing minimized the effect of build angle on the Ra. The 180-degree build angle is recommended when SLA printing an anterior restoration, as it provides the lowest Ra values and also requires a minimal support area and minimal number of support structures.

Surface evaluations of a nanocomposite after different finishing and polishing systems for anterior and posterior restorations.

This study aims to evaluate the effects of different finishing and polishing (F/P) systems on gloss and surface morphology of a new nanocomposite. Thirty discs of Filtek Universal Restorative material (3 M, ESPE) were prepared and divided into six groups (n = 5). Group A and B followed F/P protocols for anterior restorations, whereas Group C and D for posterior ones. Group E represented the control (covered by Mylar strip) and Group F represented the nanocomposite placement by means of clinical hand instruments; Groups E and F did not undergo F/P procedures. Among the polished groups, Group B showed the highest values (68.54 ± 7.54 GU), followed by Group A and D (46.87 ± 5.52 GU; 53.76 ± 2.65 GU). Finally, Group C (37.38 ± 4.93 GU) displayed the lowest results. Overall, Group E showed the highest gloss values (93.45 ± 8.27 GU), while Group F presented the lowest ones (1.74 ± 0.64 GU). Surface analysis revealed that Group A, C, and D displayed a smooth surface. Group B showed the lowest irregularities. Group E exhibited the most uniform superficial morphology. On the other hand, Group F displayed the most irregular one. In conclusion, using the tested material, only two protocols achieved appropriate gloss values. Then, clinicians might use the protocols of Group B and Group D, for anterior and posterior restorations, respectively.

The effect of pre-treatment levels of tooth wear and the applied increase in the vertical dimension of occlusion (VDO) on the survival of direct resin composite restorations.

ObjectivesTo investigate the effects of the level of pre-treatment tooth wear and increasing the VDO on the performance of direct resin composite restorations for the rehabilitation of pathological tooth wear. MethodsFull-mouth (pre-treatment) grading was performed on digital greyscale scan records for 34 participants (35.3 ± 8.4 years) with signs of moderate-to-severe generalised tooth wear, using the Tooth Wear Evaluation System and the Basic Erosive Wear Examination. Each participant received full-mouth direct resin composite restorations, with increased VDO. The post-treatment increase in the VDO was determined. Recalls were planned after 1 month, and after 1, 3, and 5 years. Three ‘levels’ of restoration failure were described. The effects of the variables on the frequencies of restoration failure were calculated with a multivariable Cox regression, (p < 0.05). Results1269 restorations were placed with a mean observation period of 62.4 months. Increasing the VDO by 1 mm significantly reduced the risks of all levels of anterior restoration failure (HR ≤ 0.62, p ≤ 0.025). A higher anterior BEWE surface score was associated with increased risks of Level 2- & 3- failures, (HR ≥ 1.29, p ≤ 0.019). Premolar restorations showed lower risks of Level 2- & 3- failure, compared to the molar restorations, (HR ≤ 0.5, p ≤ 0.005). ConclusionLevels of pre-treatment wear and the applied change in the VDO significantly affected failure risk. Clinical relevanceDirect resin composite restorations for the rehabilitation of wear should be made as voluminous as possible, respecting the presenting biological, functional, and esthetic constraints.