Silane and acid etch cross contamination of dentin and composite reduced µ-tensile bond strength.

Objectives: To investigate whether acid etch contamination of silane-treated composite influenced repair bond strength and whether silane contamination on dentin influenced composite bond strength to dentin. Materials and methods: Forty composite blocks stored in water for 4 weeks were divided into four groups. Specimens in groups 1-3 were coated with Bis-Silane and contaminated with acid etch + water spray (group 1) or water spray (group 2). Group 3 was not contaminated. Group 4 was untreated. The occlusal third of 60 third molars was cut off, ground flat, and divided into three groups. After etching, the surfaces in groups A and B were contaminated with Bis-silane. The contaminated surfaces in group A were re-etched.Each composite repair group and composite-dentin group was divided into two subgroups receiving Adper Scotchbond 1 XT or Clearfil SE Bond 2 adhesives followed by a composite build up. After ageing for 3 months, specimens were sectioned into 1.1 mm × 1.1 mm rods for tensile testing and strength calculated at fracture. The fracture was examined using microscope. Results: Bis-Silane surface treatment increased the repair bond strength. Contamination with acid reduced the strength of the repair bond. Similar results were obtained for both adhesives. Tooth surface contamination with silane reduced the bond strength between dentin and composite. Additional acid etching or water spray on silane contaminated dentin did not influence the weakened bond strength. Most fractures were adhesive type. Conclusions: Silane contamination on etched dentin and acid etch contamination on silanized composite surfaces significantly reduced tensile bond strength.

Quantification of Color Variation of Various Esthetic Restorative Materials in Pediatric Dentistry.

Aim of study: The goal of this paper is to find an association between the staining capacity of dental restorations used in pediatric patients and food items and to develop an optimum model to predict the most informative factor that causes the highest amount of color change through machine learning algorithms. Background: Color changes in restorative materials occur as a result of intrinsic and extrinsic factors, such as the type of restorative material, food items used, polished status of the material, and time interval. Materials and methods: This was an "in vitro study" conducted at Aligarh Muslim University, Aligarh, Uttar Pradesh, India. The study included 200 specimens, that is, 40 in each group A (orange juice), group B (Amul Kool Café), group C (Pepsi), group D (Amul Kesar Milk), and group E (artificial saliva). The materials were glass ionomer cement (GIC), resin-modified glass ionomer cement (RMGIC), microhybrid composite resin, and nanohybrid composite resin. These were further divided into polished and unpolished groups. The optimum modeling of the prediction of color change in materials by different effective factors was done by machine learning decision tree. We applied two algorithms: Chi-square automatic interaction detector (CHAID) and classification and regression tree (CART). In prediction modeling in the decision tree by CHAID and CART, color change is taken as the dependent variable, and group (type of restorative material), food items, time interval, and polished status are taken as independent variables. Results: The various beverages caused significant color variation due to different pigmentation agents. The agent that caused the highest color change was Kool Café. The Kesar Milk had the lowest pigmentation capacity. The greatest color variation was found on Glasionomer FX-II submerged in Pepsi and the least on Ivoclar Te-Econom Plus in Kesar Milk. The mean absolute error for the training dataset in the CART model and CHAID model is 0.379 and 0.332, and for the testing data set, it is 0.398 and 0.333, respectively. Therefore, the prediction of color change by the CHAID model is optimum, and we found that the restorative materials have a maximum predictor importance of 0.86 (86%), time interval 0.07 (7%), food items 0.04 (4%), and polished status has the least importance, that is, 0.03 (3%). Conclusion: The staining capacity of restorative material highly depends on the material itself, the initial time interval, and least on the food items used. Clinical significance: The clinical performance of dental restorations could be affected by various beverages consumed by children. This study thus provides important clinical insights into esthetic dentistry by offering valuable information on long-term color stability and the effect of polishing on common esthetic restorative materials used in pediatric dentistry. How to cite this article: Varshney P, Khan SY, Jindal MK, et al. Quantification of Color Variation of Various Esthetic Restorative Materials in Pediatric Dentistry. Int J Clin Pediatr Dent 2024;17(7):754-765.

Repair of fractured metal-ceramic restoration using CAD/CAM technologies. Case report.

Fractures in esthetic ceramic veneering are one of the potential failure modes during prosthetic treatment. Depending on the type of chipping fracture, there are three possible outcomes: replacement, restoration repair, or polishing of the fractured area. Computer-aided design and manufacturing (CAD/CAM) technologies provide new methods to the maintenance and repair of fixed metal-ceramic restorations. Here, we report the case of a 68-year-old patient who came to the dentist with comcerns about his appearance due to spontaneous gingival bleeding and a fracture in the ceramic veneering of a metal-ceramic restoration. The patient reported occurrences of bruxism. The proposed treatment plan included consultation with a cardiologist, periodontal treatment, polishing of the chipped areas, repair of the fractured zone with an exposed metal core, and fabrication of a mouth guard. Once the ceramic veneering on the palatal and buccal sides of the retainers had been completely removed, a digital impression was obtained and sent to the dental lab so that milled zirconium veneer could be manufactured. The veneering was cemented the next day using the standard prosthetic field preparation process and resin-modified glass ionomer cement. In conclusion, fixed metal-ceramic restorations that have fractured can be successfully repaired using CAD/CAM methods and materials.

"Evaluation of Silver Diamine Fluoride Modified Atraumatic Restorative Treatment (SMART) on hypomineralized first permanent molar"- a randomized controlled clinical study.

BACKGROUND: Restoring first permanent molars affected with molar incisor hypomineralization (MIH) is challenging. Focusing on improving the quality of life for children affected by MIH, at least until the complete eruption of first permanent molars to receive full coverage, to decrease the hypersensitivity and to be able to perform proper oral hygiene measures, the purpose of this study was to compare silver modified atraumatic restorative technique (SMART) versus the conventional restoration and fluoride varnish application on moderate to severe hypomineralized molars. The comparison considered the restoration survival, hypersensitivity, and digital surface area changes after one year follow up. METHODS: Twenty-eight children were selected (20 girls and 8 boys) with at least 2 MIH molars with the same defect severity. The study comprised 2 groups; MOD group (moderate hypomineralized molar severity) and SEV group (Severe hypomineralized molar severity) (n = 28 tooth). Each group was further subdivided into 2 subgroups according to the technique of restoration: SMART subgroup and CONV subgroup (high viscosity glass ionomer restoration and fluoride varnish application) (each = 14 tooth). Evaluation was done in terms of the restoration survival (6 months and 12 months), hypersensitivity at 1 weak, 6 months and 12 months and occlusal surface area changes at 12 months). Professional Fluoride varnish application and home prophylaxis using MI paste were the protocol for each child patient. RESULTS: There was no significant difference between the 4 subgroups, regarding tooth restoration integrity at 6-months vs. 12-months. However, a statistically significant difference in tooth restoration integrity between the 4 subgroups at 12-months (P = .049). Also, the hypersensitivity score, there was a statistically significant difference between the 4-time intervals (P < .001) and a statistically significant difference in surface area changes between the 4 subgroups. CONCLUSIONS: Selective removal of carious tissue and SMART restoration, combined with dental home and professional preventive measures every 3 months maintained the integrity of restorations in severely and moderately affected permanent molars up to 1 year. TRIAL REGISTRATION: The study protocol was retrospectively registered on Clinical Trials (NCT05931822-05/ 07/2023).

Impact of refrigeration of different Resin composite restorative materials on the marginal adaptation in class II restorations.

BACKGROUND: The pre-polymerization temperature of resin composite restorative materials could influence their adaptation to cavity details. As a current debate is existing about the refrigeration of resin composite restorative materials, this study was designed to assess the effect of refrigeration of 3 types of resin composite restorative materials with different matrix systems on their marginal adaptation in Class II restorations. METHODS: Forty-two sound maxillary molars, each with two separated Class II cavities, were used in this study. The teeth were assigned into 3 main groups (n = 14) according to the restorative /adhesive system used; an Ormocer-based composite (Admira Fusion/Futurabond M+, Voco GmbH, Cuxhaven, Germany), a methacrylate modified Ormocer-based (Ceram.X SphereTEC One/Prime&Bond Universal, Dentsply Sirona GmbH Konstanz, Germany), and a methacrylate-based (Tetric N-Ceram/Tetric N-Bond Universal, Ivoclar Vivadent AG, Schaan, Liechtenstein). Each group was then divided into 2 subgroups (n = 14) according to the gingival margin location; 1 mm above and 1 mm below the cemento-enamel junction (C.E.J). Each subgroup was further divided into 2 categories (n = 7) according to the storage temperature; stored at room temperature or stored in refrigerator at 4°- 5° C. Epoxy resin replicas were observed under scanning electron microscope (SEM) to examine the marginal gaps. A gab scoring system was used to assess the marginal adaptation of each restoration by giving scores on the basis of measurements of the maximum marginal gaps. The data obtained were statistically analyzed using the Chi-square test at a significance level of p < 0.05. RESULTS: None of the tested groups exhibited 100% gap-free margins irrespective of margin location or storage temperature. For both storage temperatures, no statistically significant difference was observed among all tested groups either with margins located above or below C.E.J (p > 0.05). As well, there was no statistically significant difference when comparing both marginal locations for each material (p > 0.05). Regarding the effect of storage temperature, statistically significant difference was only observed between the room-temperature stored groups with margins located above C.E.J and their corresponding groups stored in refrigerator (p < 0.05). CONCLUSION: The refrigeration of resin composite restorative materials prior to the restorative procedures revealed a deleterious effect on marginal adaptation of the restorations with margins located in enamel regardless the type of material used.

Evaluation of alveolar bone loss among diabetic patients with class II amalgam restorations.

The relationship between Class II amalgam restorations and alveolar bone loss among diabetic and non-diabetic patients is evaluated at the Faculty of Dentistry, Najran University, KSA. Hence, we compared type 2 diabetic (n = 32) and non-diabetic patients (n=32) using clinical assessments and imaging techniques. Parameters such as bone loss rate, extent, age, and periodontal condition (plaque index and Gingival Index) were analyzed. Analysis of data shows that diabetic patients on average have higher bone loss.

Analysis of 8.5 mm Long Dental Implants Provided with Splinted or Solitary Implant Restorations: A 15-Year Prospective Study.

Background/Objectives: The long-term effects of implant properties, such as implant length, platform switch, and crown splinting, on peri-implant health require more investigation. Therefore, the aim was to assess the long-term peri-implant health and patient satisfaction in a patient cohort, obtained from two prospective randomized controlled trials, who received 8.5 mm long dental implants, with either splinted or solitary suprastructures and with or without a platform switch, over a period of 15 years. Methods: One hundred and twenty-two patients received either one or two 8.5 mm long dental implants (223 dental implants) with and without platform switch, restored with either a solitary (n = 89) or a splinted (n = 134) restoration in the posterior region. Clinical and radiographical parameters and patient satisfaction were prospectively recorded at 1 month, and 1, 5, and 15 years after the placement of the restoration. Patient satisfaction was recorded with a self-administered questionnaire using a 5-point scale and a visual analog scale (0-10). Results: Eighty-one patients with one hundred and fifty-four implants were assessed after a 15-year follow-up. The clinical parameters were low and comparable between the implant types (OsseoTite XP Certain, OsseoTite XP Certain Prevail, NanoTite XP Certain, NanoTite XP Certain Prevail, PalmBeach Gardens, FL, USA) over time. The implants that incorporated a platform switch showed significantly less bone loss than the implants without a platform switch (-0.37 mm, 95% CI -0.69 to -0.05 mm, p = 0.024 and ß = -0.47, 95% CI -0.80 to -0.14, p = 0.006). The implants with splinted restorations experienced more bone loss over time compared to the implants with solitary restorations (0.39 mm, 95% CI 0.15-0.63, p = 0.002). Patient satisfaction was high after 15 years. Conclusions: All the tested dental implants with 8.5 mm length provide satisfactory 15-year results with regard to the clinical and radiographical parameters as well as patient satisfaction. The platform-matched implants were associated with more bone loss compared to the platform-switched implants, and the implants with splinted crowns portrayed more bone loss than the solitary implant crowns.

Influence of the Composition of Provisional Luting Materials on the Bond Strength of Temporary Single-Tooth Crowns on Titanium Abutments.

In addition to zinc oxide-based cements, resin-based materials are also available for temporary cementation. The aim of this in vitro study was to determine the influence of the different material compositions on temporary bonds. In nine test series (n = 30), temporary bis-acrylate single-tooth crowns were bonded onto prefabricated titanium abutments with nine different temporary luting materials. After simulating an initial (24 h, distilled water, 37 °C), a short-term (7 days, distilled water, 37 °C) and a long-term provisional restoration period (12h, distilled water, 37 °C; thermocycling: 5000 cycles) in subgroups (n = 10), the bond strength was examined using a combined tensile-shear test. Statistical analysis was performed by univariate analysis of variance or a non-parametric Kruskal-Wallis test, followed by post hoc tests. Of the three resin-based materials, two showed significantly higher bond strength values compared to all other materials (p < 0.001), regardless of the storage procedure. The resin-based materials were followed by eugenol-free and eugenol-containing zinc oxide materials. Significant intragroup differences were observed between the composite-based materials after all storage periods. This was only observed for some of the zinc oxide-based materials. The results show that under in vitro conditions, not only the composition of the temporary luting materials but also the different storage conditions have a significant influence on temporary bonds.

Anterior Endocrowns as An Alternative to Core Crown restorations: A Systematic Review.

Restoring extensively damaged endodontically treated teeth presents a challenging task due to the state of biomechanical deterioration affecting long-term prognosis. Therefore, the study aims to assess and compare the biomechanical performance of endocrowns and post core-crown restorations in anterior endodontically treated teeth with severe coronal structure loss. Following PRISMA guidelines, a systematic search was conducted using PubMed, Scopus, Web of Science, and Google Scholar for articles published from January 2014 to March 2024. Two independent reviewers screened and selected studies based on the predefined inclusion and exclusion criteria. The included studies were analyzed using the QUIN tool for risk of bias assessment in in-vitro studies. Additionally, the biomechanical outcomes were collected for qualitative comparative analysis. Twelve studies were included in this systematic review. In most studies, Endocrowns demonstrated comparable fatigue resistance under load to failure to post core-crown restorations. Endocrowns without ferrule exhibited a higher rate of debonding but had significantly more repairable failures. Conversely, post core-crown restorations demonstrated higher fracture resistance with the presence of ferrule, but were associated with more catastrophic failure patterns. Additionally, endocrowns generated lower stress levels in both the restorative material and the luting material compared to post core-crown restorations. Among the tested materials, lithium disilicate ceramics provided the best biomechanical properties. Overall, the studies included provided sufficient information for most evaluation criteria of the QUIN risk of bias assessment tool. Endocrowns are a viable and conservative approach for restoring endodontically treated anterior teeth, offering comparable biomechanical performance to traditional post core-crown restorations and less catastrophic failures. The findings of this systematic review suggest that endocrown restorations, especially with lithium disilicate ceramics and proper ferrule design, can improve fracture resistance and longevity of rehabilitated teeth, enhancing patient outcomes for severely damaged anterior endodontically treated teeth.

Multifactorial Contributors to the Longevity of Dental Restorations: An Integrated Review of Related Factors.

PURPOSE: This integrated review aims to identify and analyze the multifactorial contributors to the longevity of direct restorations, focusing on tooth-, patient-, and dentist-related factors. MATERIALS AND METHODS: A search of the literature was performed using an electronic database, PubMed/Medline, Web of Science, and Scopus, on papers published between 1980 and 2024. The titles and abstracts of papers that evaluated aspects categorized into tooth-related, patient-related, and dentist-related factors influencing restoration failure were selected and screened. Full-text assessments were conducted, and the extracted data were compiled, summarized, and synthesized. The reference lists of the collected papers were also screened, and relevant citations were included in this review. Data were gathered from clinical and laboratorial studies, systematic reviews, and meta-analyses to provide a comprehensive understanding of restoration longevity. RESULTS: Among the tooth-related factors, multiple-surface restorations, deep margins, tooth location, and tooth vitality significantly impact restoration survival. Patient-related factors such as medical conditions, risk predictors of caries, age, sex, parafunctional habits, smoking, periodontal health, number of restorations, and socioeconomic status all play crucial roles. Regarding dentist-related factors, the decision-making process, age, experience, and dentist manual dexterity are vital aspects. Furthermore, the technique used, including isolation methods for moisture control, as well as the type of dental practice (large group vs. small practice), notably influenced the restoration survival. CONCLUSIONS: The longevity of dental restorations is influenced by a complex interplay of tooth-related, patient-related, and dentist-related factors. Strategies to improve restoration outcomes should consider all these multifactorial contributors. Continuing professional education, diligent patient guidance on the factors that influence restoration survival, careful material selection and restorative technique, and tailored individual treatment are crucial factors to reduce failure rates and improve the lifespan of restorations.

Comparative Strength Study of Indirect Permanent Restorations: 3D-Printed, Milled, and Conventional Dental Composites.

Background/Objectives: Limited research has been performed to assess the strength of resin-bonded 3D-printed restorations. Based on that, this study investigates the impact of different manufacturing methods on the fracture load of indirect composite restorations (ICRs) following an aging process. Methods: Three manufacturing techniques-conventional (CRC), milled (MRC), and printed (PRC)-were evaluated using 60 specimens, each with a diameter of 10 mm and a thickness of 1.0 mm. Sandblasting with Al2O3 particles was employed to optimize the bonding process, significantly influencing surface roughness parameters (Ra, Rz, RSm). All specimens were bonded to the dentin analog using composite resin cement and subjected to either 10,000 thermocycles (TC) or storage (ST) at 37 °C in distilled water. Fracture load assessments were performed using a universal testing machine. A finite element analysis was conducted to assess stress distribution. Results: Two-way ANOVA results indicated that the manufacturing method significantly affected mean fracture load values (p < 0.001), with PRC showing the highest mean fracture load (4185 ± 914 N), followed by MRC (2495 ± 941 N) and CRC (599 ± 292 N). The aging protocol did not have a significant impact on fracture load. Conclusions: This study revealed that 3D-printed resin composite exhibited comparable strength to milled resin composite when adhesively cemented, suggesting it is a promising option for indirect composite restorations based on its mechanical performance. However, further research is needed to evaluate its bond strength and optimal surface treatment methods to prevent early debonding.

Effect of different preparation designs and material types on fracture resistance of minimally invasive posterior indirect adhesive restorations.

PURPOSE: To evaluate the impact of various preparation designs and the material type on fracture resistance of minimally invasive posterior indirect adhesive restorations after aging using a digital standardization method. MATERIALS AND METHODS: One-hundred sixty human maxillary premolars free from caries were assigned into 16 groups (n = 10): bevel design on enamel substrate with mesial box only (VEM), butt joint design on enamel substrate with mesial box only (BEM), bevel design on enamel substrate with mesial and distal box (VED), butt joint design on enamel substrate with mesial and distal box (BED), bevel design on dentin substrate with mesial box only (VDM), butt joint design on dentin substrate with mesial box only (BDM), bevel design on dentin substrate with mesial and distal box (VDD), and butt joint design on dentin substrate with mesial and distal box (BDD). Each group was restored with pressable lithium disilicate (LS2) or disperse-filled polymer composite (DPC) materials. Adhesive resin cement was used to bond the restorations. The specimens were aged for 10,000 thermal cycles (5°C and 55°C), then 240,000 chewing cycles. Each specimen was subjected to compressive axial load until failure. A two-way analysis of variance (ANOVA) test followed by a post hoc Tukey test was used to analyze the data (α = 0.05). RESULTS: The two-way ANOVA test revealed a significant difference among designs (p < 0.001) and materials (p < 0.001) with no interaction effect (p = 0.07) between the variables. The Post hoc Tukey test revealed that the VEM group exhibited the highest mean fracture resistance value, while the BDM group had the lowest. The LS2 groups showed the highest mean fracture resistance values. The DPC groups showed a restorable fracture pattern compared to the LS2 groups. CONCLUSIONS: Bevel and butt joint designs with mesial or distal boxes are recommended for conservative posterior indirect adhesive restorations in premolar areas. Enamel substrate improved load distribution and fracture resistance. DPCs have restorable failure patterns, while pressed LS2 may harm underlying structures.

Use of Computer Digital Techniques and Modern Materials in Dental Technology in Restoration: A Caries-Damaged Smile in a Teenage Patient.

Prosthodontic treatment of developmental age patients presents a significant challenge to the dentist. The growth and development of the stomatognathic system must be considered in treatment planning. Temporary prosthetic restorations must be regularly inspected and recemented, and final prosthetic restoration should not be delivered until the growth of the body is complete. In addition, due to the complex nature of morphological and functional disorders during the developmental period, simultaneous prosthetic and orthodontic treatment may be required. The case presented in this article is a 16-year-old boy with severe tooth destruction caused by untreated caries disease and poor oral hygiene. The patient required conservative, endodontic, and surgical treatment to restore the occlusion and aesthetics to allow the proper development of the masticatory organ. This article also presents the treatment case of a young patient with damaged crowns in the upper arch, which were restored with standard root-crown posts and cores and temporary 3D-printed composite crowns.

Evaluating the Impact of Prosthetic Material Choices on the Clinical Outcomes of Implant-Supported Restorations.

Background: By resolving the difficulties associated with missing teeth, implant-supported restorations have emerged as a key component of contemporary dentistry. The choice of prosthetic materials is crucial in establishing the durability and clinical efficacy of these restorations. Methods: A prospective design was used at a tertiary care hospital with 150 patients receiving implant-supported restorations. Depending on which of the three prosthetic materials were utilized for their prosthesis-ceramic, metal, or polymer-the patients were randomized into one of three groups. Clinical assessments were carried out at baseline and at regular intervals for a minimum follow-up period of [insert time]. These evaluations included implant stability, peri-implant health, restorative integrity, patient satisfaction, and maintenance needs. Results: When compared to metal and polymer alternatives, ceramic restorations showed superior implant stability (75.2 ± 3.6 N cm), peri-implant health (1.8 ± 0.4), and restoration integrity (92%). Ceramic restorations had the greatest patient satisfaction ratings (8.5 ± 1.2), but there was no statistically significant difference between the material groups. Restorations made of polymers showed the greatest maintenance requirements (2.0 ± 0.9). Conclusion: The choice of prosthetic material has a major impact on how well implant-supported restorations function clinically. Ceramic restorations performed better in terms of restoration quality, peri-implant health, and implant stability, demonstrating their appropriateness for producing positive long-term outcomes.

Crafting Confidence: A Comprehensive Case Study of Full-Mouth Reconstruction Utilizing Implant-Supported Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) Zirconia Restorations.

A 67-year-old male patient reported to the department with a chief complaint of tooth mobility. The patient presented with a medical history of diabetes for which he was on medication, and he also reported a history of chronic periodontitis. After a thorough assessment of the patient, a proper treatment plan was designed, which included full-mouth rehabilitation, prior to which the patient was advised full-mouth extraction. Six implants were inserted into the mandibular and maxillary arches as part of the treatment. After the implant was placed, zirconia was the preferred choice for the restoration because of its superior aesthetic results. Polyvinyl siloxane impression material was used to make implant impressions after an eight-week healing period. The case report provides the technique for the current approach to full-mouth rehabilitation with all six concepts of implant placement. In these situations, it is crucial to plan and insert implants correctly and adhere to the entire treatment plan. Restorations were performed using the latest computer-aided design/computer-aided manufacturing (CAD/CAM) technologies for a more aesthetically pleasing result. The case study highlights the significance of meticulous preparation and implementation for the accomplishment of successful full-mouth rehabilitation.

Direct Composite Restorations on Permanent Teeth in the Anterior and Posterior Region - An Evidence-Based Clinical Practice Guideline - Part 1: Indications for Composite Restorations.

PURPOSE: This German S3 clinical practice guideline offers evidence-based recommendations for the use of composite materials in direct restorations of permanent teeth. Outcomes considered were the survival rates and restoration quality and process quality of the manufacturing process. Part 1 of this two-part presentation deals with the indication classes. MATERIALS AND METHODS: A systematic literature search was conducted by two methodologists using MEDLINE and the Cochrane Library via the OVID platform, including studies up to December 2021. Six PICO questions were developed to guide the search. Recommendations were formulated by a panel of dental professionals from 20 national societies and organizations based on the collected evidence. RESULTS: Composite materials are a viable option for the direct restoration of cavity Classes I-V and may also be used for restorations with cusp replacement, and tooth shape corrections. In the posterior region, direct composite restorations should be preferred over indirect composite inlays. For Class V restorations, composite materials can be used if adequate contamination control and adhesive technique are ensured. CONCLUSION: The guideline is the first to provide comprehensive evidence on the use of direct composite materials. However, further long-term clinical studies with comparators such as (modified) glass-ionomer cements are necessary. Regular updates will detail the future scope and limitations of direct composite restorations.

Influence of impression method and shoulder design on the marginal adaptation of CAD/CAM nanoceramic resin onlay restorations.

Objective: This in-vitro study investigates the influence of two different impression techniques and two shoulder designs on the marginal adaptation of computer-aided design/computer-aided manufacturing restorations. Methods: Forty mandibular first premolars were cast into dental arch models for this in vitro study. Fragile cusps and concavities on the mesial-buccal-occlusal surfaces were treated, with 2 mm of the occlusal surface removed. Teeth were categorised into two groups based on shoulder preparation. Digital scanning using a 3Shape 3D scanner identified them further for allocation into conventional and digital impression subgroups. The restorations were created from nanoceramic resin blocks using prescribed guidelines. Microscopic evaluation assessed the restoration's marginal adaptation, with data analysed using SPSS 27.0. The level of significance was set at p ≤ 0.05. Results: Digital intraoral scanning consistently demonstrated smaller marginal gaps than the traditional impression method, regardless of shoulder preparation, with the differences being statistically significant (p < 0.05). Furthermore, shoulder preparation significantly reduced the marginal gaps in both the digital and traditional impression groups (p < 0.05). Conclusions: The onlay preparation design with a shoulder led to restorations with improved marginal adaptation compared with the design with no shoulder. Direct digital impression techniques produced restorations within a better marginal discrepancy than traditional impressions.

Fracture resistance and fractographic analysis of pressable glass-ceramics with different partial coverage designs for maxillary premolars.

BACKGROUND: Partial coverage concepts have met the main goal of conservative dentistry. Vonlays, which combine features of veneers and onlays, are a recent alternative to full coverage designs and overlay partial coverage restorations. This in vitro study was conducted to compare the fracture resistance of the newly introduced pressable zirconia-reinforced lithium silicate with pressable lithium disilicate ceramic and to determine the optimal preparation design for partial coverage on upper premolars. METHODS: Fifty-two duplicated epoxy resin dies were prepared following vonlay and overlay preparation guidelines. For each preparation (n = 26), the specimens were divided into two subgroups to be restored with lithium disilicate (IPS e.max Press) or zirconia-reinforced lithium silicate (Vita Ambria) (n = 13 each). Ceramic vonlays and overlays were bonded using dual cure resin cement, subjected to thermomechanical fatigue, and the load to fracture was tested by using a universal testing machine. The specimens were fractographically analyzed via scanning electron microscopy (SEM). The normality of the fracture resistance data was checked using the Shapiro‒Wilk test and Q‒Q plots, and two-way ANOVA was used to assess the effect of the type of preparation and ceramic material on the fracture resistance. RESULTS: The group of overlays restored with zirconia-reinforced lithium silicate showed the highest mean fracture load (1218.69 N), while the group of vonlays restored with lithium disilicate had the lowest mean fracture resistance (967.15 N). The effect of preparation design and material type on fracture resistance was significant for both factors, p = 0.003 and p < 0.0001, respectively. Different features of the fracture surfaces, such as arrest lines, hackles, and directions of crack propagation, were observed. CONCLUSIONS: Zirconia-reinforced lithium silicate exhibited greater resistance to fracture compared to lithium disilicate, making it a potential substitute for partial coverage restorations. Additionally, the overlay showed superior fracture resistance when compared to the vonlay preparation design.

Double Monolithic Protocol: The Solution to Fluorescence Limitations.

OBJECTIVE: The present paper aims to demonstrate the incorporation of the double monolithic protocol (DMP) into a chairside digital workflow to reproduce the fluorescence properties of natural teeth with chairside monolithic restorations when exposed to different light sources. CLINICAL CONSIDERATIONS: A female patient reporting dissatisfaction with her upper anterior teeth was rehabilitated using seven veneers and a three-element bridge. The DMP was applied to the bridge, which consisted of a primary lithium disilicate framework to which leucite-reinforced glass ceramic veneers were cemented. The fluorescence of the different substrates and ceramic restorations was evaluated throughout the rehabilitation process, under 365 and 405 nm light. CONCLUSIONS: The DMP allows chairside procedures to be optimized by achieving predictable, mechanically resistant, and esthetic restorations. CLINICAL SIGNIFICANCE: The DMP is a new chairside solution for developing ceramic restorations with optimal esthetics and combined mechanical properties, eliminating the need for sintering or glazing procedures.

Knowledge and Practice of Endocrown Restorations Among Dental Students and Dentists in Sirte, Libya.

Background Restoring endodontically treated teeth has long posed a challenge for clinicians. The endocrown (EC) is an innovative and conservative restoration designed for teeth with severely damaged coronal structures. ECs offer performance that is equivalent to or even exceeds that of traditional post-core-crown treatments. Purpose This web-based cross-sectional survey aimed to evaluate the level of knowledge and practical experience regarding ECs as post-endodontic prostheses among dental students and practitioners in Libya. Methods A 22-item structured questionnaire was created using Google Forms and distributed to final-year students, interns, faculty at the College of Dentistry at Sirte University, and practicing dentists in Libya. The sample comprised 290 participants. The questionnaire was divided into three sections: the first assessed demographic variables such as gender, education level, country of graduation, and workplace; the second evaluated knowledge of ECs through 11 questions; and the third focused on EC practice, also comprising 11 questions. Statistical analysis was conducted using IBM SPSS Statistics for Windows, Version 21.0 (Released 2012; IBM Corp., Armonk, NY, USA). Results A total of 50.7% of participants indicated that EC restorations are suitable for molar teeth, 41.4% noted that a butt joint finish line is used for EC preparation, and 66.9% preferred all-ceramic materials for ECs. Nearly 72.8% reported that computer-aided design/computer-aided manufacturing technology is employed for EC fabrication. Additionally, 61.7% agreed that EC designs offer higher fracture resistance compared to conventional crowns. Despite this, 64.5% of participants had not cemented an EC in their clinic in recent years. Significant differences in knowledge and practice regarding ECs were observed across various factors, including gender, education level, country of graduation, and workplace. Conclusion Most participants demonstrated an acceptable level of knowledge and practical experience with EC restorations. Therefore, incorporating ECs as a major topic in the postgraduate prosthodontics curriculum is recommended.