Clinical and Experimental Dental Research最新文献

Objective: This study aimed to compare the force degradation of intermaxillary elastics (IE) in vitro and in vivo while stretching the IE to a precise diameter.

Materials and methods: IE 3/16″ medium Dentaurum from five different batches of packaging were analyzed. The in vivo study involved 10 volunteers, of which 100 IE were examined. To achieve three times the original diameter of the elastic, the distance between the upper canine and the lower dental arch was measured. Buttons were then placed in the mouth accordingly, and IE and passive aligners were inserted for five sessions of 48 h each. To investigate in vitro, 100 IE were placed in an incubator set at 37°C in a humid environment and stretched three times their diameter. The force of the elastics was measured in both investigations using a force meter at 0, 2, 8, 24, and 48 h.

Results: In all patients except one, the three times diameter distance extended from the upper canine to the lower second premolar. The force degradation in vivo at 2, 8, 24, and 48 h was 20.58%, 26.78%, 34.81%, and 38.56% and in vitro was 16.38%, 22.83%, 28.32%, and 30.78%.

Conclusions: The amount of stretching of IE varies for each patient when using standard insertion points. The force of IE decreases exponentially, the force degradation in vivo being higher. The clinician must consider the force decrease when advising the patient of the time interval to change the elastics.

Objectives: Temporomandibular disorder (TMD) encompasses various clinical issues affecting the temporomandibular joint, masticatory muscles, and surrounding structures. Common symptoms include pain, joint and muscle tenderness, and limited jaw movement. Diverse treatment options have been utilized to manage TMD. However, evidence of the combined modality treatment approach is scarce. This pilot trial aimed to evaluate the effectiveness of combining stabilization splint therapy (SST) with low-level laser therapy (LLLT) in managing TMD.

Material and methods: This pilot parallel randomized clinical trial included 30 patients with TMD. Patients were randomly allocated equally into three treatment groups: SST, LLLT, and combined treatment (CT). Outcomes, including pain and functional limitations, were measured at baseline, 1, 2, 3, and 4 weeks after the start of each treatment.

Results: CT was significantly more effective in reducing pain in patients with TMD compared to LLLT and SST. Although patients in the LLLT group reported significantly reduced pain, they still had higher pain scores compared to the SST group at certain time points, indicating that LLLT was not as effective as SST. Most functional limitations were improved over time, more consistently within the CT group, but without significant differences between the three groups. Patients were more satisfied with CT compared to LLLT and SST.

Conclusions: The superior results of the CT group over the SST and LLLT groups were evident in this pilot trial's outcomes. The combined modality treatment approach seems to yield the greatest improvement for TMD patients.

Objectives: To assess the effect of occlusion and implant number/position on stress distribution in Kennedy Class II implant-assisted removable partial denture (IARPD).

Materials and methods: IARPDs were designed in six models: with one implant (bone level with a platform of 4 mm and length of 10 mm) at the site of (I) canine, (II) between first and second premolars, (III) first molar, (IV) second molar, or two implants at the sites of (V) canine-first molar, and (VI) canine-second molar. A conventional RPD served as control. Loads were applied according to the group function (GF) (500N load was applied to the left canine/premolar/molar teeth in the ratio of 1:1:2) or canine guidance (CG) (125N load was to the canine tooth) occlusions. Maximum displacement and Von Mises Stress in different components were analyzed by finite element analysis (FEA).

Results: The control model showed the highest displacement followed by the IARPD with a canine implant in both occlusal schemes. In GF, the maximum and minimum jaw stress were recorded in IARPDs with canine implants (16.45 MPa) and canine-first molar implants (13.47 MPa), respectively. In CG, the maximum and minimum jaw stress was recorded in IARPD with first/second premolar implant (15.91 MPa) and canine-first molar implants (12.38 MPa), respectively. The highest stress in resin, framework, and implant(s) was noted in IARPD with canine implant in both schemes. The lowest stress in the implant(s) was recorded in IARPD with canine-second molar implants in GP and IARPD with canine-first molar implants in CG.

Conclusion: Dental implants reduced the total displacement of IARPDs, increased stress in mechanical components, and did not affect stress distribution in biological components. Insertion of two implants decreased implant stress. The GP scheme caused greater stress on mechanical components.

Background: Recently, products with antibacterial properties derived from medicinal plants have increased as an alternative to conventional drugs. Thus, this study aimed to formulate and evaluate the antibacterial activity of an experimental gel based on Grindelia tarapacana essential oil in a bacterial consortium.

Material and methods: The composition of the essential oil (EO) was determined using gas chromatography-mass spectrometry (GC-MS). The antibacterial activity of the EO against Streptococcus mutans ATCC 25175, Streptococcus sanguinis ATCC 10556, and Streptococcus salivarius ATCC 13419 was evaluated using an Agar disc diffusion and minimum inhibitory concentration methods. Five formulations of the experimental gel were prepared at 0.25%, 0.5%, 1%, 1.5%, and 2% (v/v). The antibacterial susceptibility test was evaluated using an Agar-Well diffusion assay against a bacterial consortium of S. mutans, S. sanguinis, and S. salivarius. The physical properties, pH, spreadability, gel morphology, phase separation, and drug release were evaluated. The experimental gels were compared with a chlorhexidine gel. Data were analyzed with one-way ANOVA and Kruskal-Wallis tests with a significant level of 5%.

Results: The major components of the EO were bornyl acetate, α-isomethyl-E-nerolidol, germacrene B, E-nerolidol, α-cedrene-epoxide, fokienol, and 10-epi-γ-eudesmol. All formulations were effective in inhibiting bacterial growth. The 2% concentration presented inhibition zones (18.14 ± 1.01 mm) similar to those observed for the chlorhexidine gel (p > 0.05). All formulations were stable, without signs of separation, with adequate physical properties, and no significant differences were observed regarding the drug content with the chlorhexidine gel (p > 0.05).

Conclusions: The experimental gels based on G. tarapacana EO presented good physicochemical properties and were highly effective in inhibiting the growth of a cariogenic bacterial consortium.

Background and objective: Tongue squamous cell carcinoma (TSCC) is the most prevalent oral cancer. Despite considerable advancements in treatment, the 5-year survival rate remains relatively unchanged. Langerhans cells (LCs) play an important role in antitumor immunity. Therefore, we attempt to evaluate the correlation between the LC count and disease prognosis.

Materials and methods: Histopathologic slides from 24 cases, with at least 2 years of follow-up, were selected and categorized into early-stage (12 cases) and advanced-stage (12 cases) groups. An additional 12 slides of normal tissue comprised the control group. Immunohistochemical staining with the CD1a marker was performed to analyze the density of LCs. Statistical analysis assessed the impact of CD1a immune expression on patient survival and other variables such as age, gender, stage, and histopathological grade.

Results: Comparison of CD1a+ cell counts across the three groups revealed a significant decrease in the advanced group. Furthermore, a lower count of CD1a+ cells correlated with poorer disease-free survival (DFS) (p < 0.001) and overall survival (OS) (p = 0.049). Although the CD1a+ cell count did not independently affect OS significantly (p = 0.210), it did show a significant impact on DFS as an independent variable (p = 0.002).

Conclusion: The significant correlation between CD1a expression and patients' prognosis and survival rates suggests that CD1a+ cells could serve as a crucial prognostic factor in the management and treatment of TSCC.