The Effect of Average Value Mounting and Facebow Transfer on Condylar Guidance Settings in a Semi-Adjustable Articulator - A Comparative Study using Digital Lateral Cephalographs in Edentulous Patients.

BACKGROUND: While we attempt to restore occlusion in completely edentulous patients there is a consensus among clinicians to articulate the cast using average value and avoid performing facebow transfer. Various studies question the application of facebow transfer in the fabrication of removable complete denture fabrication. AIM: This study was therefore aimed to study the effect on condylar guidance with casts mounted by the facebow method, Bonwill's method, and radiographic method. METHODS: A cross-sectional study was performed using casts of edentulous patients attending the Department of Prosthodontics. After establishing a tentative jaw relationship using wax occlusal rims in the edentulous participants, the casts were mounted by Bonwill's method and the facebow transfer method to a semi-adjustable articulator. Protrusive records of the subjects were used to program the articulator to obtain the condylar guidance values. Digital lateral cephalographs were made both in centric and protrusive jaw relationships. The mandibular condyles were then traced and overlapped to obtain radiographic values. The condylar guidance values obtained by Bonwill's method, facebow method and radiographic method were compared using Wilcoxon's signed rank test and Mann-Whitney U test. The SPSS Statistics for Windows (Version 21.0. Armonk, NY, USA:IBM Corp.), and, at a probability value of 0.05, the significance of every statistical test was predetermined. RESULTS: Ten edentulous 45-70 year olds participated in the study. The mean discrepancy between radiography and facebow methods was 12.8° for the right side and 12.7° for the left (P < 0.005). The difference between radiography and Bonwill's methods was significant (P < 0.005), with a mean difference of 34.3° for the right side and 34.7° for the left side. The difference between Bonwill's method and the facebow method was significant (P < 0.005), with a mean difference of 21.5° for the right side and 22° for the left side. CONCLUSION: The condylar guidance values obtained by clinical methods (Bonwill's and Facebow) were significantly lesser (P < 0.005) compared to the values obtained by radiographic method.

Fingernail form as a post-extraction guide for selecting the maxillary central incisor tooth form in the Saudi Arabian population: A novel application of CAD software.

Background: Human teeth and nails have demonstrated similar factors genetically, embryologically, and morphologically. The fingernail form may be used as a post-extraction guide for selecting the tooth form. Aim: To evaluate the correlation between the maxillary left central incisor tooth form with the left index, middle, and ring fingernails in the Saudi Arabian population. Materials and Methods: A descriptive cross-sectional study with purposive sampling was done among 200 Saudi participants. The maxillary left central incisor and the left index, middle, and ring fingernail were scanned using an intraoral scanner. The 3D digital images were converted to 3D models. The tooth form (tooth length, tooth width, and tooth shape) and nail form (nail length, nail width, and nail shape) were measured using the CAD software. Pearson's correlation coefficient and T-test were used for statistical analysis (P < 0.05). Result: A significant correlation exists between tooth length and nail length, with a maximum correlation toward index nail length (P = 0.015). A significant correlation exists between tooth width and nail width, with a maximum correlation toward ring nail width (P = 0.002). A significant correlation exists between tooth length and nail length in females with a maximum correlation toward index nail length in females (P = 0.001). The mean percentage of similarity between tooth and nail shape (index, middle, and ring) in males and females shows a highly significant difference between them (P = 0.001). The results indicate that the tooth and nail shape are similar (70 to 90%) based on the criteria set by the software. Conclusion: A definite correlation exists between maxillary central incisor tooth form and fingernail form. The fingernail form may be used as a post-extraction guide for selecting the maxillary central incisor tooth form in the Saudi Arabian population.

A comparative study on the influence of third point of reference on condylar guidance settings in a semi-adjustable articulator with lateral cephalographs: An in-vivo study.

AIM: The study aimed to evaluate the effect on condylar guidance values with casts mounted by facebow transfer (Guichet's point as the third point of reference), Bonwill's, and radiographic method. MATERIALS AND METHODS: The dentulous subject's casts were mounted to a semi-adjustable articulator (Artex Type AR) after facebow transfer with Guichet's point as the third point of reference and also by Bonwill's method. Protrusive records made earlier were utilized to program the right and left side condylar guidance value. Two digital lateral cephalograms were made, one in centric relation, and one in protrusion and the condyles were traced and overlapped. The condylar guidance readings obtained by Bonwill's method, facebow transfer, and lateral cephalometric tracings were compared in this study using the SPSS (Version 17.0 Illinois, Chicago, USA) software. RESULTS: The condylar guidance values obtained from Bonwill's and the facebow transfer method (p < 0.001) was lesser than the radiographic method. The values obtained by casts mounted to the Bonwill's method differed significantly (p < 0.001) from the other two methods. CONCLUSION: The values obtained by facebow transfer were closer to the radiographic values whereas the values obtained by Bonwill's method mounting differed markedly.

Comparative evaluation of three gingival displacement systems: an in-vivo study.

OBJECTIVE: The study aimed to evaluate and compare gingival retraction in terms of lateral and vertical displacement with a magic foam cord, conventional retraction cord, and laser. PATIENTS AND METHODS: This in-vivo experimental study was performed on 60 patients. Three different gingival retraction systems were used to evaluate the amount of vertical and lateral displacement. The study sample units were divided into three groups of 20 units each. Tooth preparation was done for a metal-ceramic restoration with a subgingival finish line. Gingival displacement was accomplished with a magic foam cord, conventional retraction, and laser. Vertical and Lateral displacement was measured by the distance from the finish line to the free gingival margin in pre and post-displacement casts with the help of a traveling microscope. Stereomicroscopic images of the impression of ×10 resolution were scanned into an image analyzer to measure the lateral displacement. The data analyzed using one-way ANOVA and Bonferroni test were used to determine the significant difference at the p<0.05 level. RESULTS: Independent group analysis comparing the vertical and lateral displacement within each group showed a statistically significant difference (p<0.05) with mean maximum vertical and lateral displacement achieved by lasers (0.73 and 0.61) followed by magic foam (0.37 and 0.21) and least by retraction cord (0.21 and 0.13), respectively. CONCLUSIONS: Laser provided the maximum lateral and vertical displacement of the gingival margins, followed by magic foam cord, and the least with conventional retraction, which was statistically significant.

Influence of information source regarding COVID-19 knowledge among the undergraduate dental students during the early lockdown: a multi-national study.

OBJECTIVE: To assess the influence of information sources on the knowledge regarding COVID-19 among undergraduate dental students in India, Saudi Arabia, Malaysia, and Turkey. SUBJECTS AND METHODS: An online questionnaire in a Google form link was circulated among the target population via various online platforms. It consisted of 14 close-ended questions assessing these students' knowledge and source of COVID-19-related information. SPSS software version 21.0 (IBM Corp., Armonk, NY, USA) was used to compute descriptive statistics, Chi-square test, independent t-test, and ANOVA tests for comparing various variables, and a p-value<0.05 was considered statistically significant. RESULTS: The study yielded 809 responses from dental undergraduate students from India, Saudi Arabia, Malaysia, and Turkey. Dental students from Turkey reported a higher mean knowledge score of 7.91±1.34 and 7.88±0.58 for Malaysian dental students. In contrast, the lower scores were achieved by Saudi Arabia (7.36±1.22) and India (7.37±1.21) dental students, and the findings were statistically significant (p<0.05). The study population used various sources to attain information regarding COVID-19. Most respondents (63.1%) utilized information regarding COVID-19 from multiple sources rather than single sources (36.9%). CONCLUSIONS: Reliable and validated information sources resulted in higher knowledge scores. Turkey and Malaysia dental students reported a higher mean knowledge score and the lowest for Saudi Arabia and India dental students. There is increased popularity of social media platforms as information sources.

Reciprocal actions of Magnetic Resonance Imaging with dental prostheses and oral tissues - awareness among the dentists.

OBJECTIVE: MRI (Magnetic Resonance Imaging) does not use ionizing radiation and provides a comparatively better resolution. It is an important tool for the diagnosis of problems related to the head and neck area. It has various applications in dentistry, including MRI-based planning for implant placement. Previously, studies have been performed to assess its medical use, but very few studies have been conducted on its applications in dentistry. MATERIALS AND METHODS: A pre-validated online questionnaire was distributed through various messenger groups and social media. The questionnaire comprised two sections to collect demographics and assess the knowledge and awareness among dentists about the interactions between dental prostheses and materials with MRI. RESULTS: In the present study, 63.20% of respondents indicated that MRI provided a good view of the implant sites, TMJ and salivary gland tumours, but the majority believed that metallic and titanium implants do not interact or cause artefacts on MRI imaging. CONCLUSIONS: We concluded that dental undergraduates and graduates had limited knowledge of the interactions of dental materials and prostheses with MRI. Dentists should be aware of interactions of MRI with the various dental materials and prostheses and possible image distortion to ensure the safety of the patient.