The International journal of prosthodontics最新文献

Purpose: To evaluate the circumferential bone level and morphologic changes in the posterior mandibular ridge of mandibular overdenture wearers submitted to conventional and immediate loading through CBCT at 1 and 3 years.

Materials and methods: In total, 20 participants who received two narrow-diameter implants (NDIs; Facility-Equator, Neodent; 2.9 × 10 mm) were randomly allocated to the conventional loading (CL; n = 10) or immediate loading (IL; n = 10) group. CBCT scans were performed in each group to analyze the vertical bone level (VBL) and horizontal bone level (HBL) around the implants, analyzed together with the posterior bone remodeling of the mandible measured at distances of 5, 10, 15, and 20 mm from the mental foramen (L1 to L4, respectively). Differences between groups were verified using Student t test at a significance level of 5%.

Results: The IL group showed a significantly higher HBL in the first year (P = .028) and a significantly higher VBL in the third year (P = .032), with an HBL of -0.22 mm and VBL of -0.59 mm, respectively. After the third year, the percentage of cortical and medullary height indicated that the IL group presented a significantly higher percentage of cortical bone height (40.1 ± 9.3 mm) compared to the CL group (31.8 ± 5.8 mm) at position L1 (P = .05). No difference was found for posterior ridge remodeling (P > .05).

Conclusions: The IL group showed slightly higher HBL and VBL values and locally displayed more replacement of medullary bone by cortical bone. However, circumferential bone levels in the IL group were still clinically acceptable, and the posterior resorption rate remained stable after 3 years of function, irrespective of the loading type.

Purpose: To evaluate the tensile strength of five different thicknesses of two resin cements placed between two titanium surfaces, before and after aging.

Materials and methods: One hundred grade-5 titanium models were used, each composed of two surfaces simulating a semiprecision attachment for overdenture and its housing in the framework. Samples were cemented using two different resin cements (SoloCem and OT-Cem). Five groups representing five different cement thicknesses (from 50 to 250 μm) were created by varying the housing diameter. Half of the samples underwent a tensile strength test 24 hours after luting, while the other half underwent a tensile strength after 30,000 thermic cycles from 5°C to 55°C. Shapiro-Wilk and ANOVA with post-hoc tests were performed to relate the tensile strength to the variables: cement type, thermal aging, and cement thickness (P < .05).

Results: Statistical differences were found between the cements both at T0 and T1; the mean values of tensile strength of SoloCem were three times higher than those of OT-Cem. The thermic cycles determined a reduction of the tensile force values for both cements; statistical evidence was found only for the SoloCem, except for the 100 μm thickness group. Significant differences were also found between the cement thicknesses of both cements, with 50 μm and 100 μm expressing the best tensile strength. Most of the fractures were of cohesive nature.

Conclusions: SoloCem showed a higher tensile strength than OT-Cem but was more stressed by aging. For each group, the cement thickness influenced the tensile strength values with an inverse relationship.

Purpose: To analyze the association of temporomandibular disorders (TMDs) and somatic symptoms with the psychologic variables of personality, coping, and distress in young adults. Physical and psychologic correlates were also explored, along with the risk factors for TMDs/somatization.

Materials and methods: Participants were enlisted from a local university, and the presence of TMDs and somatic symptoms was determined with the Short-form Fonseca Anamnestic Index and Patient Health Questionnaire-15. The psychologic variables of personality, coping, and distress were assessed with the Big-Five Personality Inventory-10; brief-COPE Inventory; and Depression, Anxiety, Stress Scales-21, respectively. Statistical evaluations were performed with Mann-Whitney U test, Spearman correlation, and logistic regression analyses (α = .05).

Results: Among the 455 participants (mean age: 22.7 ± 1.2 years), 18.2% and 5.7% had TMDs and medium-to-high somatization, respectively. Participants with TMDs exhibited substantially higher somatization and psychologic distress scores than those with no TMDs. Significant differences in TMDs, conscientiousness, extraversion, and psychologic distress scores were observed between participants with no-to-mild and medium-to-high somatization. The association between TMD and somatization scores was weak but significant. Neuroticism and dysfunctional coping style were moderately correlated to general distress, depression, anxiety, and stress (rs = 0.44 to 0.62).

Conclusions: Findings suggest that anxiety is the main risk factor for the presence of TMDs and medium-tohigh somatization in nonclinical young adults, while conscientiousness is a protective factor for somatization.

Purpose: To evaluate the effect of toothbrushing on the surface roughness (Sa), roughness profile (Rv), gloss units (GU), and surface morphology of three glazed ceramics.

Materials and methods: Specimens (n = 7) were made from the following different CAD/CAM materials and evaluated: lithium disilicate-based glass ceramic (EM); zirconia-reinforced lithium silicate glass ceramic (CE); and 6 mol% yttria partially-stabilized zirconia (IN). IPS e.max CAD (EM) and InCoris (IN) specimens were sintered, and all groups were prepolished and glazed according to the manufacturer's recommendations using IPS Ivocolor Glaze Paste (Ivoclar Vivadent) or Universal Overglaze High Flu (Dentsply/Sirona). Sa, Rv, GU, and morphology were analyzed before and after brushing at 30,000, 120,000, and 180,000 cycles. The data of Sa and GU were analyzed with ANOVA two-way and post hoc Tukey tests (α = .05). Rv was analyzed with Kruskal-Wallis and Student-Newman- Keuls tests. Surface morphology was analyzed qualitatively.

Results: Sa decreased significantly after 180,000 toothbrushing cycles for all materials tested. CE showed higher Rv than EM and IN, and IN showed the highest GU after 180,000 toothbrushing cycles, which promoted a polishing effect for all materials.

Conclusions: Long-term toothbrushing did not jeopardize the glazed surface of all tested materials compared to lack of brushing.

Purpose: To investigate the medium-term survival of Dalbo-Rotex retention elements, identify potential risk factors for complication or loss, and consider economic factors.

Materials and methods: Patients treated with Dalbo-Rotex retention elements in a university setting were retrospectively identified and examined. Clinical data comprised assessments of the dental, periodontal, endodontic, and prosthetic situation, including radiographic analysis. Patient satisfaction was quantified with visual analog scale questionnaires. Five-year Kaplan-Meier plots for relative survival and success rates were calculated.

Results: The 45 included patients had a total of 76 Dalbo-Rotex retention elements. Of these, 12 Dalbo-Rotex elements failed and complications occurred in 42.1% of elements, equating to a survival rate of 84.2% and a success rate of 47.4% after a mean observation period of 49.2 ± 52.4 months (range: 6 to 219 months). The 5-year cumulative survival and success rates were 62.4% (95% CI: 44.0% to 88.4%) and 35.6% (95% CI: 23.8% to 53.2%), respectively. Patients' self-assessment of prosthesis retention was rated at 82 (IQR 40 to 92.2) with low pain perception at 4.5 (IQR 0 to 30). Probing pocket depth levels were significantly reduced in patients adhering to a regular recall interval compared with those with longer intervals.

Conclusions: Chairside Dalbo-Rotex retention elements are a straightforward chairside method for prosthesis retention that achieve good survival over medium-term follow-ups with high patient satisfaction. This technique is therefore a viable alternative to cast post copings and can be particularly valuable for patients with limited financial resources.

Purpose: To evaluate the clinical and patient-reported outcomes of a minimally invasive suturing technique for esthetic crown lengthening surgery (ECLS).

Materials and methods: A total of 15 patients who underwent ECLS were treated using the described suturing technique. Clinical parameters, including plaque index (PI), gingival index (GI), bleeding index (BI), papilla index score (PIS), early wound healing index (EHI), visual analog scale (VAS), pink esthetic score (PES), and white esthetic score (WES), were recorded at baseline, immediately postsurgery, and during follow-up visits spanning 5 days to 24 months. Two-sample t test was performed to evaluate statistical significance (α = .05).

Results: All patients (100%) reported a high level of satisfaction, with stable high postoperative VAS scores. From baseline to 5 days postoperative, there was no statistically significant increase in PI, although there was a slight deterioration observed in GI (0.13 ± 0.23, P < .05) and BI (0.49 ± 0.55, P < .05). Early wound healing (EHI 1) was achieved by all patients at 5 days postsurgery. Additionally, 3 patients exhibited changes in PIS within the initial 3 months following surgery, after which all patients attained an optimal degree of papilla fill (degree III).

Conclusions: The application of the minimally invasive esthetic suturing technique in ECLS demonstrates favorable outcomes in terms of patient satisfaction and long-term stability. However, the assertion of its superiority over conventional suturing methods for ECLS necessitates substantiation through rigorous investigation via well-designed randomized controlled clinical trials.

Purpose: To evaluate the facial esthetics of complete denture treatment using a 3D analysis of the lower third of the face before and after treatment by comparing and correlating measurements.

Materials and methods: A total of 31 edentulous patients were enrolled, and 3D images were captured before (T1) and after (T2) complete denture delivery. Twelve landmarks were established in the face. Linear, angular, surface, and perimeter measurements were evaluated and compared with paired t test. The delta (Δ) values (T2-T1) were assessed using Spearman correlation to verify the associations between all measurements according to the facial parameters (α = .05).

Results: Statistical differences were identified in the lower third of the face in the linear measurement Sn-Gn (P = .006), the angular measure Tright-Pg-Tleft (P = .004), and at the surface of the lower third of the face (P = .001). All measurements were statistically different in the labial protrusion area: the nasolabial angle (Prn-Sn-Ls), the surface, and the perimeter (P = .001). In the lip evaluation, statistical differences were observed in the linear (Ls-Li), surface, and perimeter measurements (P = .001).

Conclusions: The facial esthetic proportions of the linear and perimeter measurements increased and the angles of sealed lips and nasolabial and lower facial convexity decreased after complete denture delivery. The present study showed a clinically important correlation between linear and angular measurements that should help restore facial esthetics, providing metrics that can aid the clinician in facial composition.

Purpose: To investigate the influence of milling parameters on the durability and fracture force of resinbased composite crowns during in vitro aging simulation.

Materials and methods: Identical molar crowns (n = 8 per group) were milled from resin-based composite crowns (Grandio, VOCO Dental) with different processing speeds (soft, normal, fast) or levels of detail (very high, high, low) from 98-mm disks. One group was milled wet to investigate the influence of cooling. The influence of polishing was tested in two groups. All crowns were adhesively bonded on standardized resin-based composite molars. Aging was performed with thermal cycling and mechanical loading (2 × 3,000 × 5°C/55°C, 2 minutes, H20 dist., 1.2 × 106 force at 50 N). Fracture forces were determined (v = 1 mm/minute, Z010, Zwick Roell).

Results: For statistical analysis, Pearson correlation, one-way ANOVA, and Bonferroni post hoc tests were used (α = .05). All crowns survived thermal cycling and mechanical loading (TCML) without any failures. The fracture values varied between 1,237.3 ± 326.7 N and 3,308.6 ± 655.8 N. Significant (P < .001) differences between the individual manufacturing approaches were detected. Failure was categorized as a fracture of the crown and partial loosening of the crown. No different failure pattern was observed between the tested systems.

Conclusions: A medium level of detail seems to be ideal to achieve the highest fracture forces. No relationship existed between machine speed and fracture force. Fracture force was not affected by wet grinding. In individual cases, polishing reduced crown fracture values due to reduced wall thickness.

The aim of this short communication is to present a technique to rehabilitate severely discolored teeth with computer-aided designed and computer-aided manufactured (CAD-CAM) zirconia crowns. After confirming the absence of periapical lesions and sufficient crown structure, any caries or fractured restorations can be removed and replaced by an interim composite restoration. A shoulder subgingival preparation is performed and scanned with an intraoral scanner to design a CAD-CAM zirconia crown using a monolithic zirconia material. This crown is highly polished using a specific polishing kit, but not glazed. This technique is suggested to be useful in cases of dark discolored teeth due to staining endodontic materials such as resorcinol-formaldehyde resin.