Contemporary Clinical Dentistry最新文献

Background: Facial aging is associated with the loss of soft tissue fullness. Perioral signs of facial aging can add years to individuals' appearances and even affect their facial expressions in smiling and nonsmiling images.

Aims: To evaluate the influence of the nasolabial fold on the visual perception of esthetics and age in the elderly, eye-tracking and a visual analog scale were used.

Material and methods: This study applied a cross-sectional study using 40 laypeople. Facial images of an elderly woman were modified to include facial expression lines such as nasolabial folds and marionette lines with no folds, intermediate, and accentuated depths folds. Eye tracking was implemented to measure the average number of fixations. Heat maps and dot maps were generated using eye-tracking software. A visual analog scale of attractiveness and age perception questionnaire were also incorporated into the study. Statistical analysis was performed using a significance of (P<0.05).

Results: The majority of visual attention was paid to the eye and mouth areas. In the images with no folds, the right eye attracted a greater degree of fixation. In the images in which nasolabial folds were accentuated, the mouth area served as an area of high fixation. No statistical difference was observed between the groups in which smiling images were viewed. Nonsmiling images demonstrated significant differences between groups for variables including time until first fixation, complete fixation time, and number of fixations on the eyes and hemifaces. Old age and diminished attractiveness were associated with attenuated nasolabial folds, especially in nonsmiling images.

Conclusion: The facial lines and expressions of elderly female individuals were assessed by laypeople using eye-tracking, showing that the deeper one's nasolabial folds, the more aged and less attractive one appears, especially in nonsmiling images. Smiling pictures were perceived to be more attractive and youthful; these perceptions should be considered in the search for improved esthetic results, whether in dental or facial esthetic treatments.

Background: Partially demineralized dentin is remineralizable when mineral ions are made available in the near vicinity. Nanoparticles (NPs) have wide applications in remineralization process. Zinc promotes remineralization and has a synergistic effect when combined with fluoride. Hence, zinc oxide and calcium fluoride NPs were considered for dentin remineralization.

Aim: The aim of this study was to evaluate the remineralizing ability of zinc oxide and calcium fluoride NPs on demineralized dentin individually and in combined form.

Settings and design: This was an in vitro study.

Materials and methods: Forty-eight dentin disks were prepared from the crowns of 12 extracted human molars and were allocated into four groups of 12 each, i.e., Group I - nano zinc oxide (nZnO), Group II - nano calcium fluoride (nCaF₂), Group III - combined group (nZnO + nCaF₂), and Group IV - artificial saliva (AS, control group). The specimens were demineralized with 37% phosphoric acid and placed in the respective remineralizing solutions for 24 h and 1 month. Calcium (Ca) and phosphorous (P) uptake was measured using energy-dispersive X-ray spectrometry, and structural changes were analyzed using scanning electron microscopy (SEM).

Statistical analysis: One-way analysis of variance, Student's t-test, and post hoc Tukey's test were used for statistical analysis.

Results: At 1-month interval, all the groups showed an increase in Ca/P ratio, with highest being the combined group (4.24), followed by nCaF₂ (3.30), nZnO (1.71), and AS (1.31) groups, and these differences were statistically significant (P = 0.000). On SEM analysis of dentinal samples at 1 month, depositions were evident in intertubular regions, wherein the highest deposits were observed in the nZnO group, followed by nZnO + nCaF₂ and nCaF₂ groups.

Conclusion: Dentin samples subjected to remineralization with aqueous solutions of nZnO and nCaF₂ showed an increase in calcium and phosphorous uptake and also dense granular depositions were evident in intertubular regions of dentin.

Background: Age estimation is integral to science of forensic odontology and plays an important role in human identification. Pulp volume estimation using cone-beam computed tomography (CBCT) to derive age can be very useful as it is noninvasive and can be applied on individuals of all ages.

Aims and objectives: The study aimed to estimate the chronological age-based pulp and tooth volume (PTV) ratios in adults from Uttar Pradesh, India, using CBCT and voxel counting dental software.

Materials and methods: Thirty-six CBCT scans were allocated into three Groups, I, II, and III (12 in each group) randomly to study the pulp volume of lateral incisor, canine, and first premolar, respectively. PTV was calculated by image segmentation method using Xelis Dental software. A correlation between chronological age with PTV was established using derived regression equations.

Statistical analysis: All the data were subjected to statistical analysis using Statistical Package for Social Sciences version 16.0.

Results: Estimated age and standard error were determined. Standard errors of estimates were 11.24 years (LI), 7.78 years (C), 9.89 years (PM) group, lowest being for canines. The estimated age was compared with the chronological age. The difference between the chronological age and the estimated age by the derived equation for the present study was statistically nonsignificant (P = 1.00).

Conclusions: The results of the study show the feasibility of calculation of PTV ratios on CBCT to estimate the age for the set population with canine as the best predictor of age for the present study population.

Background: The aim of the study was to evaluate the remineralizing potential of prepared solutions of eggshell powder (ESP) and nano-hydroxyapatite (nHA) on the surface roughness and microhardness of bleached enamel.

Materials and methods: Fifty bovine anterior teeth were selected and cleaned then bleached using a chemically activated in-office bleaching agent then the teeth were randomly allocated into five groups (n = 10) according to the tested remineralizing agents (10% ESP solution, 10% nHA solution, and MI Paste Plus) into; control, bleached, bleached + ESP solution, bleached + nHA solution, and bleached + MI Paste Plus groups. Then, the teeth were tested for surface roughness and microhardness of the bleached enamel, respectively.

Results: There was a statistically significant difference in the surface roughness and microhardness values of the tested groups. The highest surface roughness mean value was found in bleached enamel group, while the least mean value was found in the control group. The highest mean microhardness value was found in the bleached enamel + ESP solution group, while the least mean value was found in the bleached enamel group.

Conclusions: The application of the tested remineralizing agents following the bleaching procedure had improved the surface roughness and microhardness of the bleached enamel. ESP and nHA present promising and potent remineralizing agents.

Background: Temporary anchorage devices or mini-implants have gained great attraction due to its capability to provide absolute anchorage, low cost, versatility, and can be loaded immediately after placement.

Aims and objectives: The aim of this study is to use FEA analysis to assess the strain and insertion torque of mini-implants on a bone model at two distinct angulations of 45° and 90°.

Materials and methods: A computer-aided three-dimensional (3-D) model representing alveolar bone and mini-implants were developed using ANSYS software. Computed tomography scan images of the implant and the alveolar bone were taken and exported in DICOM format for 3-D image processing. The thickness of the bone model is 1 mm. Ti6Al4V orthodontic single and double threaded mini-implants (L = 7 mm, D = 1.5 mm) were inclined at 45° and 90° on to the bone surface to measure the insertion torque and strain produced.

Results: Maximum insertion torque (MIT) for single-threaded mini implant at 45° and 90° angulations are 20.001 Nmm and 19.977 Nmm, respectively. MIT for double-threaded mini-implants obtained is 19.977 Nmm at 90° and 19.991 Nmm at 45° angulation. The strain of the bone at 90° angulation for single-threaded mini-implant is 0.00893 mm and for single-threaded mini implant at 45° angulation is 0.01257 mm. The strain in double-threaded mini-implant at 90° angulation is 0.0125 mm and that of 45° angulation is 0.01773 mm.

Conclusion: For maximum stability single-threaded mini-implant with perpendicular insertion, angle is preferred.

Context: Regeneration of periodontal tissues depend on the adhesion and development of fibrin clots to the root surface. Demineralization of the root surface ensures removal of smear layer uncovering dentin tubules and collagen matrix. Root conditioning agents were introduced to remove the smear layer and enhance the adhesion of blood components.

Aims: The aim of the study was to determine the effect of erbium, chromium-doped yttrium, scandium, gallium and garnet (Er, Cr: YSGG) laser on smear layer removal (SLR) and fibrin network formation when compared to tetracycline, and ethylene-diamine-tetra-acetic acid (EDTA) for periodontal regeneration.

Settings and design: The study was conducted at Amrita school of dentistry and the study design involves in vitro comparative study.

Subjects and methods: Forty dentinal sections were prepared from freshly extracted teeth that were periodontally affected. The samples were divided into four groups: Scaling and root planing (SRP), tetracycline, EDTA, and Er, Cr: YSGG laser. The samples were assessed using a scanning electron microscope and photomicrographs were taken and analyzed for removal of smear layer, blood component adhesion (BCA), and fibrin network formation.

Statistical analysis used: Analysis of variance test and Kruskal-Wallis test with P < 0.05 considered to be statistically significant.

Results: There was a significant difference between Er, Cr: YSGG laser, tetracycline hydrochloride, and EDTA categories when compared with SRP categories. There was no significant difference between Er, Cr: YSGG laser, tetracycline, and EDTA according to SLR scoring and BCA scoring.

Conclusions: It can be concluded that Er, Cr: YSGG laser-treated samples presented complete elimination of smear layer, formation of fibrin network, and BCA along with desensitizing effect for a better reduction in dentin hypersensitivity.

Gingival recession is a commonly encountered chief complaint in a dental office, most commonly presenting as pain or sensitivity on intake of food or sometimes just seen as an esthetic concern which may present in a localized or generalized form. Such interest toward dental esthetics has encouraged clinicians to formulate newer minimally invasive surgical techniques which are short but still deliver predictable long-term benefits in restoring the patient's smile. One such method was evaluated in the present short communication where a commercially available, biodegradable, and volume-stable collagen membrane was used to manage gingival recession instead of donor grafts. The clinical parameters which were assessed after a period of 9 months demonstrated an increased width of attached gingiva and overall tissue thickness after surgical intervention. These findings along with successful mean root coverage of the upper left canine would seem to challenge the results obtained while using similar procedures and donor grafts, the age-old gold standard bio-filler. The dawn of esthetic dentistry is here with more emphasis on how physical appearance bolsters confidence and morale among younger individuals. Among the various complaints concerned with patient`s esthetic, periodontal plastic surgery is one of the more challenging procedures. The real obstacle while performing such procedures is achieving complete or partial root coverage over an avascular bed, whereas multiple variables seem to affect the overall clinical outcome.