Clinical evaluation of cemented and adhesively resin-bonded monolithic and partially layered zirconia and lithium disilicate crowns.

Purpose: Zirconia and lithium disilicate crowns are very popular dental restorations. The cement type and layering technique used can profoundly affect the clinical performance of these crowns.This retrospective study is designed to investigate the success rate of cemented and adhesively bonded monolithic and partially layered zirconia and lithium disilicate crowns placed in faculty practice settings. Materials and Methods: Patients who had received zirconia or lithium disilicate crowns at the faculty practice were invited for clinical examination. The examiner used the modified United States Public Health Service (MUSPHS) evaluation criteria to evaluate the crowns. The crowns were either glass ionomer cemented zirconia (GIC-Zr), resin-bonded zirconia (Adh-Zr), or resin-bonded lithium disilicate (Adh-LD). The crowns were also divided into monolithic and layered groups. Inferential analysis was used to examine the differences through bivariate analysis using t-testing and one-way ANOVA. Results: Thirty-five patients, with a combined total of 218 single crowns, agreed to participate in the study. No statistically significant differences in the quality outcome variables considered were found between the groups, except for marginal adaptation, where Adh-Zr achieved significantly higher scores compared to GIC-Zr and Adh-LD. Layered zirconia and lithium disilicate crowns have significantly higher quality outcomes in terms of anatomic form, marginal adaptation, and color match compared to monolithic zirconia and lithium disilicate crowns. Conclusions: Conventionally cemented zirconia and adhesively bonded zirconia and lithium disilicate crowns are reliable treatment options with high short-term success rates. Clinical studies with longer follow-up times are needed to investigate their long-term success rates.

Tooth-cusp preservation with lithium disilicate onlay restorations: A fatigue resistance study.

OBJECTIVES: This study examined the in vitro fatigue resistance of maxillary premolars with 2 mm or 3 mm preserved cusp thicknesses restored with lithium disilicate onlays. MATERIALS AND METHODS: Premolars(N = 48) were divided into six groups. Onlays for groups 1 to 4 preserved a 3 mm functional (G1), 2 mm functional (G2), 3 mm nonfunctional (G3), or 2 mm nonfunctional (G4) buccal-lingual cusp width. Onlays for group 5 (G5, control) replaced both cusps. Group 6 (G6) samples were identical to G1 with added retentive boxes. Lithium disilicate onlays were exposed to thermocycling (10 000 cycles, 5°C-55°C, 30s/cycle) and mechanical loading (1.2 million cycles at 1.4 Hz and 70 N). All samples were examined for onlay debonding or cusp or onlay fracture. RESULTS: Failure rates were 75%(G1), 0.0%(G2), 12.5%(G3), 0.0%(G4), 0.0%(G5), and 0.0%(G6). The difference in percent failure between the groups preserving the functional cusps (37.5%) and the groups preserving the nonfunctional cusps (6.3%) was statistically significant (P = .04; 95%CI:2.11-55.66). No cusp or restoration fractures were observed; all failures were due to debonding of the restoration. CONCLUSION: Teeth with thin remaining cusps that were restored with bonded lithium disilicate onlay restorations were not prone to fracture. Retentive preparation features that physically eliminated lateral displacement prevented onlay debonding even though the ceramic-enamel margin was directly at the occlusal contact. CLINICAL SIGNIFICANCE: The use of adhesively retained lithium disilicate ceramic onlays may be a viable alternative to full coverage restorations and may challenge traditionally accepted principals related to preparation resistance and retention form of ceramic partial coverage restorations.

Predictability of dental students' performance in clinical courses based on their performance in pre-clinical and academic courses.

OBJECTIVES: Some dental schools depend on the students' academic performance for admission purposes. This research aimed at investigating the correlations between dental students' performance in specific academic courses and their pre-clinical and clinical counterparts and the correlations between students' performance in the pre-clinical practical courses and the clinical courses. METHODS: Academic and practical pre-clinical and clinical grades were retrieved for 811 students who graduated from the School of Dentistry, the University of Jordan, between 2016 and 2018. Ten courses (five academic and five practical) were selected. Pearson's rho test was used to calculate the correlations between the courses. RESULTS: Statistically significant weak-to-moderate positive correlations were found between each academic course and its pre-clinical or clinical counterparts and between pre-clinical and clinical courses. A statistically significant positive moderate correlation (p < .001) was found between students' performance in fourth and fifth year restorative clinics. CONCLUSION: The results of this study suggest that the academic performance could partially predict the practical performance in both the pre-clinical and clinical courses and that the clinical performance could partially be predicted from the pre-clinical practical performance. Moreover, students who can successfully perform the required clinical procedures in fourth year will successfully perform the required clinical procedures in fifth year. However, other confounding factors should be taken into consideration such as manual dexterity and artistic skills even though their intellectual abilities are average.

Contemporary diagnosis and management of dental erosion.

OBJECTIVE: This article is aimed at providing an overview of the topic of erosive tooth wear (ETW), highlighting the clinical signs, diagnosis, and management of dental erosion. OVERVIEW: With the increased prevalence of ETW, it is important that oral health professionals are able to recognize the early signs. Early clinical signs of dental erosion are characterized by loss of enamel texture, a silky glossy appearance, and sometimes a dulling of the surface gloss, referred to as the "whipped clay effect, cupping, and restorations 'standing proud'." The progression of ETW should be monitored by means of diagnostic models or clinical photographs. ETW can be as a result of acid attack of extrinsic or intrinsic origin. CONCLUSION: There is an increase of ETW that is being recognized by the profession. The first step in diagnosing and management is to recognize as early as possible that the process is occurring. At that point a determination of whether the primary etiology is either intrinsic or extrinsic should be made. If these findings are confirmed, appropriate prevention, and management strategies can be adopted followed by appropriate restorative therapy. CLINICAL SIGNIFICANCE: The prevalence of ETW continues to increase. It is therefore important that oral health care providers have a better understanding of the etiology, pathophysiology, and management of this condition. This review aims to provide the guidelines for diagnosis and management of dental erosion.

Clinical performance of a modified Resin-Bonded fixed partial denture (Carolina bridge): A retrospective study.

OBJECTIVES: This research aims to retrospectively evaluate the clinical performance of Carolina bridge (CB) placed at a dental school. MATERIALS AND METHODS: Data were collected from the electronic patient record system. A follow-up letter was sent to the subjects' mailing address explaining the research purpose along with a questionnaire to assess their satisfaction with the treatment. A phone interview was performed to assess patient satisfaction, function, and choice of permanent restoration. Finally, a clinical exam was conducted for patients that agreed to come for a follow-up and still had their CBs. RESULTS: Twenty-three patients with 26 resin-bonded CBs met the inclusion criteria. All patients who did the phone interview reported to be very satisfied with the treatment. Most chose to keep the CB as definitive treatment and not to move forward with implant therapy. According to the number of rebonding needed to maintain the CB, the types of survival were analyzed as 42.3% complete survival (no rebonding needed), 26.9% functional survival (rebonded once), 23.1% survival with multiple rebondings, 7.6% failure. CONCLUSION: The performance of CBs revealed highly acceptable performance with high-patient satisfaction. CLINICAL SIGNIFICANCE: Carolina ridge is an esthetic and conservative interim treatment option that can be utilized in favorable clinical situations.

Management of amelogenesis imperfecta in an adult patient: a short review and clinical report.

Objective This clinical report aims to share with general practitioners a conservative approach to treat patients with amelogenesis imperfecta (AI).Clinical considerations In relatively young patients, a conservative treatment approach is essential in order to maintain the vitality of the teeth and provide successful outcomes. In this clinical report, the diagnoses and treatment plan of an 18-year-old male patient diagnosed with AI is discussed. Composite rehabilitation followed by orthodontic treatment was considered the most conservative treatment approach for this patient.Conclusion Bonding to well-mineralised enamel can be a predictable and successful treatment approach for young patients diagnosed with AI.

Effect of Phosphorylated Chitosan on Dentin Erosion: An in vitro Study.

The aim of this study was to evaluate the antierosive effect of phosphorylated chitosan in dentin. Bovine dentin specimens were randomly distributed into the following groups: (1) no treatment (NoTx/negative control), (2) phosphate-buffered saline solution (PBS), (3) AmF/NaF/SnCl2 (positive control), (4) 0.5% chitosan solution (Chi), (5) 0.5% neutral phosphorylated (NP)-Chi, and (6) 0.5% alkaline phosphorylated (AP)-Chi. The specimens were submitted to de-remineralization treatment cycles for 5 days: 0.5% citric acid (2 min), remineralizing solution (30 min), and surface treatment according to assigned groups (2 min, 6×/day). The loss of dentin surface was measured by profilometry. Hardness and modulus of elasticity were measured using a nanoindenter equipped with a Berkovich diamond tip. The dentin surface was analyzed by scanning electron microscopy (SEM). The largest loss of dentin was observed in the No Tx and PBS groups (approx. 25 µm). The group treated with AmF/NaF/SnCl2 showed less loss of dentin (67% reduction vs. NoTx and PBS), followed by the groups treated with NP-Chi and AP-Chi (33% reduction), and Chi (18% reduction). Nanohardness and modulus of elasticity were similar in the NoTx and PBS groups, with a small increase in stiffness in all other groups. SEM revealed that the experimental solution of AP-Chi had a favorable effect on maintaining the integrity of collagen fibrils. AmF/NaF/SnCl2 showed a preserved mineralized collagen surface. Further studies are warranted to explore this nontoxic phosphorylated chitosan polymer as an effective agent in the prevention and treatment of dental erosion.