Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2021 dental literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to coverage of this broad topical area. Specific subject areas addressed, in order of the appearance in this report, include COVID-19 and the dental profession (new); prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence daily dental treatment decisions with an emphasis on future trends in dentistry. With the tremendous volume of dentistry and related literature being published daily, this review cannot possibly be comprehensive. Rather, its purpose is to update interested readers and provide important resource material for those interested in pursuing greater details on their own. It remains our intent to assist colleagues in negotiating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the patients and dental problems they encounter.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2020 professional literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to this work to cover this broad topic. Specific subject areas addressed include prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders (TMDs); sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence day-to-day dental treatment decisions with a keen eye on future trends in the profession. With the tremendous volume of dentistry and related literature being published today, this review cannot possibly be comprehensive. The purpose is to update interested readers and provide important resource material for those interested in pursuing greater detail. It remains our intent to assist colleagues in navigating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the dental patients they encounter.

Fracture rate of 188695 lithium disilicate and zirconia ceramic restorations after up to 7.5 years of clinical service: A dental laboratory survey.

STATEMENT OF PROBLEM: The use of ceramic materials has increased significantly because of high esthetic demands, low costs, and ease of fabrication. Long-term, clinically based evidence is scarce, and laboratory studies have limited relevance in determining clinical durability. PURPOSE: The purpose of this dental laboratory survey was to evaluate the fracture rate of layered and monolithic lithium disilicate and zirconia single crowns and fixed partial dentures after up to 7.5 years of clinical service. MATERIAL AND METHODS: Two commercial dental laboratories with a database system that was able to track the number of remakes because of fracture only were identified. Lithium disilicate restorations (monolithic and layered) were categorized according to restoration type (single crown, fixed partial denture, veneer, and onlay). Zirconia restorations (monolithic and layered) were categorized according to type (single crown, fixed partial denture) and then into anterior or posterior restoration. Restoration remakes due to poor fit, shade, or marginal integrity were excluded from the evaluation. Data were analyzed, and statistical significance was evaluated with chi-square tests (α=.05). RESULTS: A total of 188 695 (51 751 lithium disilicate and 136 944 zirconia) restorations were included in the analysis, with an overall fracture rate of 1.35%. Lithium disilicate monolithic single crowns had a fracture rate of 0.96%, which was significantly lower than that of layered single crowns at 1.26% (P<.05). When the different types of lithium disilicate restorations were compared, fixed partial denture (monolithic and layered) fracture rates were significantly higher than those of single crowns (P<.001). Monolithic zirconia single crowns (0.54%) fractured at a lower rate than layered zirconia single crowns (2.83%) and monolithic fixed partial dentures (1.83%) (P<.001), while layered single crowns (2.83%) had a higher fracture rate than that of layered fixed partial dentures (1.93%) (P<.001). Monolithic anterior and posterior zirconia restorations fractured at a lower rate than layered anterior and posterior zirconia restorations (P<.05). Posterior monolithic zirconia restorations fractured at a lower rate than anterior restorations, while posterior layered zirconia restorations fractured at a higher rate than anterior zirconia restorations (P<.05). CONCLUSIONS: Within the 7.5-year period, restorations fabricated with lithium disilicate and zirconia restorations had relatively low fracture rates. Monolithic restorations fractured at a lower rate than layered restorations.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

This comprehensive review of the 2019 restorative dental literature is offered to inform busy dentists regarding remarkable publications and noteworthy progress made in the profession. Developed by the Scientific Investigation Committee of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to 1 of 8 sections of the report: (1) prosthodontics; (2) periodontics, alveolar bone, and peri-implant tissues; (3) implant dentistry; (4) dental materials and therapeutics; (5) occlusion and temporomandibular disorders; (6) sleep-related breathing disorders; (7) oral medicine and oral and maxillofacial surgery; and (8) dental caries and cariology. The report targets important information likely to influence day-to-day dental treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source material when greater detail is desired. As the profession moves toward evidence-based clinical decision-making, an incredible volume of potentially valuable dental literature continues to increase. It is the intention of this review and its authors to provide assistance in negotiating the extensive dental literature published in 2019. It is our hope that readers find this work useful in the clinical management of dental patients.

Five-year success rate of resin-bonded fixed partial dentures: A systematic review.

OBJECTIVES: To assess and compare the 5-year success rate of resin-bonded fixed partial dentures (RBFPDs) fabricated from different materials. METHODS: An electronic search on 3 databases from January 1965 to March of 2017 was done for human randomized clinical trials (RCTs), and prospective and retrospective cohort studies. The key words used in the search were: Bridge OR bridges OR fixed partial OR fixed dental AND resin bonded OR Maryland OR ceramic bonded. Quality assessment was done using the Newcastle-Ottawa scale. Success was defined as the RBFPDs remaining in situ and not having experienced debonding, biological failures, or mechanical failures at the examination visit. RESULTS: Meta analyses of the included studies showed an estimated 5-year success rate of 88.18% for the metal framework RBFPDs and 84.41% for the nonmetal framework RBFPDs. The estimated 5-year success rate for each nonmetal material category was 92.07% for zirconia, 94.26% for In-Ceram alumina, and 84.83% for fiber-reinforced composite. The failure rate was not statistically significant among the single, double, and multiple retainers RBFPDs (P > .05). Technical complications were the main reason for failures. CONCLUSION: The 5-year clinical performance of RBFPDs is similar to the performance of conventional fixed partial dentures (FPDs) and implant-supported crowns. CLINICAL SIGNIFICANCE: Clinicians should consider using RBFPDs more often because their clinical performance is similar to the performance of conventional FPDs and implant-supported crowns.

Effect of time on tooth dehydration and rehydration.

OBJECTIVE: To estimate the time required for teeth to dehydrate and rehydrate and its relation to the accuracy of tooth shade selection. MATERIALS AND METHODS: Thirty-two participants were recruited, and color measurements were conducted using a spectrophotometer placed with a custom jig. After isolation, baseline measurements were made at 1, 2, 3, 5, 7, 10, and 15 min intervals to determine dehydration time. After mouth rinsing, measurements were made to determine rehydration time. CIEDE2000 values were obtained for color change between the baseline recordings and all intervals and compared to the 50:50% perceptibility and acceptability thresholds. Analysis of variance (anova) and Tukey test was used for multiple comparisons. RESULT: The tooth color changes were beyond the ΔE00 perceptibility threshold (0.8) within the first minute of dehydration (P > 0.0001). After the first minute, 87% of the teeth were beyond the ΔE00 perceptibility threshold (0.8), and 72% of the teeth were beyond the ΔE00 acceptability threshold (1.8). After 15 min of rehydration, 90% of the teeth were beyond the perceptibility threshold, and 65% were beyond the acceptability threshold. CONCLUSIONS: Shade selection procedures should be carried out within the first minute and before teeth dehydrate by means of isolation. Teeth do not rehydrate within 15 min after rehydration. CLINICAL SIGNIFICANCE: Teeth dehydration has a negative impact on shade selection, which can affect the final esthetic outcome. Shade selection should be performed at the beginning of any restorative procedure.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

This comprehensive review of the 2018 dental literature is provided to inform busy dentists about progress in the profession. Developed by the Committee on Scientific Investigation of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to one of the 8 sections of the report including (1) prosthodontics; (2) periodontics, alveolar bone, and peri-implant tissues; (3) implant dentistry; (4) dental materials and therapeutics; (5) occlusion and temporomandibular disorders; (6) sleep-related breathing disorders; (7) oral medicine and oral and maxillofacial surgery; and (8) dental caries and cariology. The report targets important information that will likely influence day-to-day treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source materials if greater detail is desired. As the profession continues its march toward evidence-based clinical decision-making, an already voluminous library of potentially valuable dental literature continues to grow. It is the intention of this review and its authors to provide assistance in navigating the extensive dental literature published in 2018. It is our hope that readers find this work useful in the clinical management of patients moving forward.

Physical Properties, Film Thickness, and Bond Strengths of Resin-Modified Glass Ionomer Cements According to Their Delivery Method.

PURPOSE: To determine the effect of changing the dispensing or mixing method of resin-modified glass ionomer (RMGI) cements on their water sorption, solubility, film thickness, and shear bond strength. MATERIALS AND METHODS: Disc-shaped specimens of RMGI cements (RelyX: Luting [handmix], Luting Plus [clicker-handmix], Luting Plus [automix], GC: Fuji PLUS [capsule-automix], FujiCEM 2 [automix], [n = 10]) were prepared according to ISO standard 4049 for water sorption and solubility tests. Furthermore, the percentage of mass change, percentage of solubility, and percentage of water absorbed was also determined. Film thickness was measured according to ISO standard 9917-2; the mean of 5 measurements for each cement was calculated. Shear bond strength for each cement was determined according to ISO standard 29022 before and after thermocycling at 20,000 cycles, temperatures 5 to 55°C with a 15-second dwell time (n = 10/subgroup). Two- and one-way ANOVA were used to analyze data for statistical significance (p < 0.05). RESULTS: Water sorptions of the RMGI cements were in close range (214-250 µg/mm3 ) with no statistical differences between counterparts (p > 0.05). RelyX Luting Plus (clicker-handmix) displayed lower solubility than its handmix and automix counterparts (p < 0.05). Film thickness of RelyX cements was significantly different (p < 0.05). RelyX Luting Plus (automix) had the lowest film thickness (19 µm) compared to its handmix (48 µm) and clicker-handmix (117 µm) counterparts (p < 0.05). GC Fuji PLUS (capsule-automix, 22 µm) was significantly lower than the automix version (GC FujiCEM 2, 127 µm) (p < 0.05). Shear bond strength of RelyX Luting Plus (automix) was significantly lower than its handmix and clicker-handmix versions (p < 0.05). GC Fuji PLUS (capsule-automix) was significantly higher than GC FujiCEM 2 (automix) (p < 0.05). The binary interaction of the two independent variables (dispensing/mixing method and thermocycling) was significant for the shear bond strengths of the GC cements only (p < 0.05). CONCLUSIONS: Change in the dispensing/mixing method of RMGI cement from the same brand may have an effect on its physical properties, in addition to its film thickness and shear bond strength. Newer, easier, and faster cement delivery systems are not necessarily better. Clinical outcomes of these differences are yet to be confirmed.

Effect of composite type and placement technique on cuspal strain.

OBJECTIVE: To compare the cuspal strain in Class II restorations made with bulk-fill and conventional composite resins. MATERIALS AND METHODS: Fifty extracted maxillary premolars were mounted into phenolic rings and divided into five groups (n = 10). Specimens received standardized MOD preparations. A two-step self-etch adhesive was applied and the preparations were restored using a custom matrix as follows: Filtek Supreme Ultra in eight 2-mm increments (FSUI); Filtek Supreme Ultra in bulk (FSUB); SonicFill in bulk (SF); SureFil SDR flow in bulk, covered with a 2-mm occlusal layer of Filtek Supreme Ultra (SDR/FSU); Tetric EvoCeram Bulk Fill in bulk (TEBF). Strain gages bonded to the buccal and lingual cusps recorded cuspal strain during restorations. End strain values were determined and data were subjected to Kruskal-Wallis testing, followed by one-way ANOVA and Tukey´s post hoc test. RESULTS: Combined strain values and standard deviations (in µÉ›) were: FSUI: 723 ± 102.8, FSUB: 929.2 ± 571.9, SF: 519.1 ± 80.2, SDR-FSU: 497.4 ± 67.6 and TEBF: 604.5 ± 127.1. A significant difference was found between group FSUI and groups SF, SDR-FSU, and TEBF. Group FSUB showed significantly higher mean strain and greater standard deviation than all other groups due to cuspal fractures, and was thus excluded from the statistical analysis. CONCLUSIONS: The tested bulk-fill composite resins exerted less strain onto tooth structure than the incrementally placed conventional composite resin, although the magnitude of generated strain was product-dependent. Bulk-filling with conventional composite resins is contraindicated. CLINICAL SIGNIFICANCE: Bulk-fill composite resins exerted less strain onto adjacent tooth structure than a traditional composite, even when that composite is was placed incrementally. Bulk-filling with traditional composite resins is unpredictable and contraindicated.

Mechanical properties of resin-based cements with different dispensing and mixing methods.

STATEMENT OF PROBLEM: Resin-based cements are frequently used in clinical practice. To reduce time and technique sensitivity, manufacturers have introduced the same brand of cement with different dispensing methods. The effect of this change on properties of the cement is unknown. PURPOSE: The purpose of this in vitro study was to evaluate the mechanical properties of resin-based cements with different dispensing systems. MATERIAL AND METHODS: Specimens of resin-based cements (n=14) PANAVIA SA Cement Plus Handmix, PANAVIA SA Cement Plus Automix, RelyX Unicem Handmix, RelyX Unicem 2 Automix, G-CEM Capsule Automix, G-CEM LinkAce Automix, Variolink II Handmix, and Variolink Esthetic Automix were prepared for each mechanical test. They were examined after thermocycling (n=7/subgroup) for 20000 cycles as to fracture toughness (FT) (ISO standard 6872; single-edge V-notched beam method), compressive strength (CS) (ISO 9917-1), and diametral tensile strength (DTS). The specimens were mounted and loaded at a crosshead rate of 1 mm/min (0.5 mm/min for FT) with a universal testing machine until failure occurred. The 2-and 1-way ANOVA followed by the Tukey HSD post hoc test were used to analyze data for statistical significance (α=05). RESULTS: Thermocycling had a significant effect in reducing the FT property of all resin-based cements except RelyX Unicem 2 and G-CEM LinkAce (P<.05). Variolink II and G-CEM LinkAce showed better FT properties than their automixed counterparts (P<.05). The overall CS of all automixed resin-based cements was better than that of their hand-mixed counterpart, except for Variolink II. PANAVIA SA Automixed and G-CEM LinkAce had higher DTS than their hand-mixed counterparts (P<.05). CONCLUSIONS: Changing the dispensing method alters the mechanical properties of resin-based cements. The clinical significance of these results is yet to be determined.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry.

PROBLEM: There are countless numbers of scientific studies published in countless scientific journals on subjects related to restorative dentistry. PURPOSE: The purpose of this article is to review pertinent scientific studies published in 2017 on topics of interest to restorative dentists. METHODS AND MATERIALS: The authors, considered to be experts in their disciplines searched the scientific literature in 7 different areas (prosthodontics, periodontics, dental materials, occlusion and temporomandibular disorders, sleep-disordered breathing, oral medicine and oral and maxillofacial surgery and dental caries). Pertinent articles were either identified and referenced or reviewed. RESULTS: A total of 437 articles in 7 disciplines were identified or reviewed. CONCLUSIONS: An impressive amount of scientific literature related to restorative dentistry was published in 2017. The evidence presented in this article can assist dentists in the practice of contemporary evidence-based dentistry.

Fracture of layered zirconia restorations at 5 years: A dental laboratory survey.

STATEMENT OF PROBLEM: The use of ceramic restorations has significantly increased in recent years because of their esthetic properties and the high cost of noble metals. However, given the lack of long-term clinical trials and the limitations of in vitro studies, the durability of ceramic restorations is still questionable. PURPOSE: The purpose of this retrospective study was to determine the fracture rate of layered zirconia restorations at up to 5 years of clinical performance by using a dental laboratory survey model. MATERIAL AND METHODS: Data up to 5 years were collected from 2 commercial dental laboratories. Layered zirconia restorations returned to the laboratory for remaking because of failure (fracture) were identified and included. Restorations were categorized as anterior or posterior. Each category was further divided into complete coverage single crowns (SCs) and multiple unit fixed dental prostheses (FDPs). Fracture rates were compared and analyzed using the chi-square test (α=.05). RESULTS: A total of 31594 restoration records were reviewed and included 13419 anterior restorations (10134 SCs and 3285 FDPs) and 18175 posterior restorations (12810 SCs and 5365 FDPs). The overall fracture rate up to 5 years for all restorations (anterior and posterior) was 3.31%. The fracture rates for anterior restorations were less than for posterior restorations. The fracture rates for anterior SCs were approximately half those of the posterior SC fracture rate, and the combined fracture rate (anterior and posterior) was 3.25%. For FDPs, anterior FDPs fractured at a rate similar to that of posterior FDPs. The combined fracture rate (anterior and posterior FDPs) was 3.47%. CONCLUSIONS: Layered zirconia restorations displayed relatively low fracture rates in the relatively short term of 5 years.

Annual review of selected scientific literature: Report of the committee on scientific investigation of the American Academy of Restorative Dentistry.

This review was conducted to assist the busy dentist in keeping abreast of the latest scientific information regarding the clinical practice of dentistry. Each of the authors, who are considered experts in their disciplines, was asked to peruse the scientific literature in their discipline published in 2016 and review the articles for important information that may affect treatment decisions. Comments on experimental methodology, statistical evaluation, and the overall validity of conclusions are included with many of the reviews. The reviews are not meant to stand alone but are intended to inform the interested reader about what has been discovered in the past year. The readers are then invited to go to the source, if they want more detail.

Effect of Finishing and Polishing on the Surface Roughness of Four Ceramic Materials after Occlusal Adjustment.

PROBLEM: Intraoral occlusal adjustment of ceramic restorations can create a significant increase in surface roughness that can produce wear of the opposing dentition. PURPOSE: To compare the surface roughness of glazed and polished monolithic ceramics with the surface roughness produced by different intraoral polishing systems on adjusted monolithic ceramics. MATERIALS AND METHODS: Milled ceramic discs (10 mm diameter × 2 mm thickness) were manufactured and distributed according to the following groups (n = 10): BruxZir (glazed and polished), Zenostar (glazed and polished), IPS Empress CAD, and IPS e.max CAD. Surface roughness, expressed as arithmetic average height (Ra ), was measured using atomic force microscope and profilometer before and after adjustment and polishing with the following intraoral polishing systems: BruxZir and Dialite ZR (for BruxZir), Zenostar and Dialite ZR (for Zenostar), and OptraFine and Dialite LD for IPS Empress CAD and IPS e.max CAD. Mean and standard error for each material and polishing system were calculated. T-test, one-way ANOVA, and Bonferroni post hoc tests were used to analyze data. RESULTS: BruxZir zirconia presented smoother surfaces with Dialite ZR system compared to BruxZir system, Zenostar zirconia shown smoother surfaces with Zenostar system compared to Dialite ZR system and IPS Empress CAD and IPS e.max CAD presented smoother surfaces with OptraFine system in comparison to Dialite LD system. CONCLUSION: All materials presented smoother surfaces at baseline than after adjustment and polishing. CLINICAL SIGNIFICANCE: This paper reveals the results of an in vitro study that provides information to clinicians regarding which intraoral polishing system will produce a smoother surface after the adjustment and polishing of IPS Empress CAD, IPS e.max CAD, BruxZir and Zenostar ceramic materials. (J Esthet Restor Dent 28:382-396, 2016).

Fracture rate of monolithic zirconia restorations up to 5 years: A dental laboratory survey.

STATEMENT OF PROBLEM: The demand for ceramic restorations has increased over the past years because of their esthetic properties and the high cost of noble metals. However, the lack of long-term clinical studies and the difficulty of interpreting in vitro studies have placed the durability of ceramic restorations in doubt. PURPOSE: The purpose of this study was to determine the failure rate of monolithic zirconia restorations due to fracture up to 5 years of clinical performance. MATERIAL AND METHODS: Data were collected over 5 years from 2 commercial dental laboratories. Restorations that were returned to the laboratory for remake because of catastrophic failure (fracture) were identified and included. Restorations were categorized as anterior or posterior. Each category was further divided into complete-coverage single crowns (SCs) and multiple-unit fixed dental prostheses (FDPs). Fracture rates were compared and analyzed using a chi-square test (α=.05). RESULTS: A total of 39827 restoration records were reviewed and included 3731 anterior restorations (1952 SC; 1799 FDP) and 36096 posterior restorations (29808 SC; 6288 FDP). The overall fracture rate of up to 5 years for all restorations (anterior and posterior) was 1.09%. Fracture rates were 2.06% for all anterior restorations and 0.99% for all posterior restorations. Fracture rates were 0.97% for anterior SCs and 0.69% for posterior SCs, and the combined fracture rate (anterior and posterior) was 0.71%. For FDPs, 3.26% restorations fractured anteriorly and 2.42% fractured posteriorly, and the combined fracture rate (anterior and posterior) was 2.60%. CONCLUSION: Within the relative short-term evaluation of 5 years, restorations fabricated from monolithic zirconia material displayed relatively low fracture rates. Anterior restorations fractured at a slightly higher rate than posterior restorations, and FDPs fractured at a rate double that of SCs.

Annual review of selected scientific literature: Report of the committee on scientific investigation of the American Academy of Restorative Dentistry.

STATEMENT OF PROBLEM: It is clear the contemporary dentist is confronted with a blizzard of information regarding materials and techniques from journal articles, advertisements, newsletters, the internet, and continuing education events. While some of that information is sound and helpful, much of it is misleading at best. PURPOSE: This review identifies and discusses the most important scientific findings regarding outcomes of dental treatment to assist the practitioner in making evidence-based choices. This review was conducted to assist the busy dentist in keeping abreast of the latest scientific information regarding the clinical practice of dentistry. MATERIAL AND METHODS: Each of the authors, who are considered experts in their disciplines, was asked to peruse the scientific literature published in 2015 in their discipline and review the articles for important information that may have an impact on treatment decisions. Comments on experimental methodology, statistical evaluation, and overall validity of the conclusions are included in many of the reviews. RESULTS: The reviews are not meant to stand alone but are intended to inform the interested reader about what has been discovered in the past year. The readers are then invited to go to the source if they wish more detail. CONCLUSIONS: Analysis of the scientific literature published in 2015 is divided into 7 sections, dental materials, periodontics, prosthodontics, occlusion and temporomandibular disorders, sleep-disordered breathing, cariology, and implant dentistry.

pH and Erosive Potential of Commonly Used Oral Moisturizers.

PURPOSE: To measure the pH values of commonly used oral moisturizers and to evaluate their erosive potential using a gravimetric analysis. MATERIALS AND METHODS: A pH analysis was performed for seven commercially available oral moisturizers using a calibrated pH meter. The pH recording was repeated three times, from three different bottles each of the same product. The gravimetric analysis was performed by submerging human dentin blocks in 5 ml of each of the moisturizers for a total of 2 weeks, with gravimetric measurements made at baseline, 24 hours, 48 hours, 96 hours, 1 week, and 15 days. Tap water was used as positive control and citric acid as the negative control. The erosive potential was descriptively analyzed, and a Spearman correlation coefficient was used to assess the relationship between the erosive potential and the pH values. RESULTS: The average pH values are as follows: Oasis, 6.3, Bioténe Moisturizing Mouth Spray, 6.1, CTx2 Spray, 9.1, Mouth Kote, 3.0, Thayer's, 6.3, Bioténe Oral Balance, 6.6, Rain, 7.1, tap water 6.99, and citric acid 1.33. The results (% of tooth structure lost) of the gravimetric analysis were as follows: Mouth Kote, 9.6%, Bioténe Moisturizing Mouth Spray, 4.6%, Oasis, 3.2%, Thayer's, 2.0%, Bioténe Oral Balance, 0.0%, Rain, 0.0%, CTx2 Spray, 0.0%, tap water 0.0%, and citric acid 18.8%. There was a significant negative correlation between the pH values and the erosive potential (r(s) = -0.73; P ≤ 0.0001). CONCLUSIONS: There is large variation in the composition and pH values of commonly used oral moisturizers, and there is a strong correlation between pH values and erosive potential of commonly used oral moisturizers. CLINICAL SIGNIFICANCE: Patients with dry mouth are at increased risk for erosion and root caries. Oral moisturizing agents are often prescribed for patients with hyposalivation to be used as needed for symptomatic relief. This study shows that there is large variation in the pH values and erosive potential of commonly used oral moisturizing agents.

Effect of Finishing Techniques on the Marginal Integrity of Resin-Based Composite and Resin-Modified Glass Ionomer Restoration.

UNLABELLED: The purpose of this study was to evaluate the marginal integrity of resin-based composite (RBC and resin-modified glass ionomer cement (RMGIC) restorations as a function of finishing technique and location of the tooth. Forty extracted third molars were assigned to four groups (N = 10) according to finishing instruments (aluminum oxide discs, fluted carbides, fine diamonds, and coarse diamond). Each specimen received standardized Class V preparations on the facial and lingual surfaces with occlusal margins on enamel and gingival margins on dentin. Each preparation was randomly assigned to be restored with either RBC or RMGIC. Specimens were finished with standardized pressure at approximately 0.16 N and evaluated at a magnification of 600× using an environmental scanning electron microscope. Occlusal and gingival margins were analyzed using an imaging software, and means for all measured gaps were calculated. Data were analyzed with a factorial analysis of variance. All possible two-way interactions were included, and the level of significance was set at 0.05. There were no statistically significant differences among the four types of finishing instruments used in the study. RBC-restored specimens exhibited significantly smaller mean marginal gaps (1.70-7.56 µm) than RMGI-restored specimens (5.24-14.24 µm) in enamel and dentin margins, respectively. There was a statistically significant difference between enamel and dentin with regard to marginal gap formation. Under the conditions of this study, marginal gap formation was not affected by finishing technique. RBC margins exhibited significantly less marginal gap than RMGI margins, whereas enamel margins resulted in significantly less marginal gap than did dentin margins. CLINICAL SIGNIFICANCE: Multiple factors can affect the marginal integrity and the longevity of direct restorations. From these, the finishing and polishing techniques are critical steps that are under the clinician's control, and proper finishing and polishing techniques should be applied for avoiding introduction of stress to the margin of the restoration. It seems that instrumentation do not play a significant role, as much as the restorative material and the substrate to bond.

Survival rate of lithium disilicate restorations at 4 years: A retrospective study.

STATEMENT OF PROBLEM: Ceramic restorations are frequently being placed due to the esthetic demand and the cost of noble metals that has increased considerably. One major disadvantage of ceramic restoration is failure of the material due to fracture by crack propagation. In vitro studies are of little clinical significance and in vivo studies are too short to support clinical success. PURPOSE: The purpose of this retrospective study was to evaluate the failure rate of lithium disilicate restorations (monolithic and layered) at 4 years. MATERIAL AND METHODS: Data were collected over 45 months from 2 commercial laboratories. Restorations were categorized into monolithic restorations and layered restorations. Each category was further classified into complete coverage single crowns, fixed dental prostheses, e.max veneers, and inlay/onlay restorations. Failure rates were compared and analyzed using Chi-square (α=.05). RESULTS: A total of 21,340 restorations were evaluated in this study and included 15,802 monolithic restorations and 5538 layered restorations. The failure rate for single crown monolithic restorations was 0.91% and was 1.83% for single crown layered restorations. For fixed dental prostheses, 4.55% of monolithic restorations failed. For e.max veneers, 1.3% of monolithic veneers fractured and 1.53% of layered veneers fractured. Of the inlay/onlay restorations group, 1.01% of monolithic restorations fractured. CONCLUSION: In the short term (45 months), restorations fabricated with the lithium disilicate material (IPS e.max) had relatively low fracture rates. Layered single crowns fractured at approximately 2 times the rate of monolithic crowns.