Determination of Maxillary Incisal Edge Position using Canine Visibility as a Guide – An In vivo Study

Purpose: To evaluate the reliability of the visibility of the central incisor & the canine for the cervico incisal positioning of anterior maxillary teeth related to age & sex while the upper lip was in repose in dentate patients & the development of rehabilitation recommendations for edentulous individuals with regard to the location of the maxillary incisal edge Methodology: 308 subjects [152 Males & 156 Females] belonging to the age of 30 to 59 years were selected using a simple stratified random technique. There were three age and sex groups: Group I was 30 to 39 years old, Group II was 40 to 49 years old, and Group III was 50 to 59 years old. The vertical distances (in mm) between the lower border of the upper lip and the right maxillary central incisal edge and canine tip were measured and recorded using adhesive tape marked with millimetres. A single examiner recorded all the measurements and the values were tabulated and subjected to statistical analysis. Results: Men in Groups I and II had maxillary central incisor exposure ranging from +6 to -1mm, whereas males in Group III had exposure ranging from +5 to -2mm. There was an exposure range of +6 to -2 mm in females in Group I, +7 to -2 mm in Group II, and +5 to -2 mm in Group III for the central incisors. While the canine exposure in Group I and II and Group III ranged from +2 to -4mm in females, the exposure ranged from +3 to -3mm in men of all ages. In all groups, females had statistically significant (P0.05) more central incisor and canine exposure than men. Conclusions: The canine visibility was less variable in all the age groups and in both males and females in comparison to the central incisor. When restoring edentulous individuals, the average canine exposure dimension can be employed for cervico-incisal location of the anterior maxillary teeth.

Influence of the Inclination of the Incisal Edge of Planas Direct Tracks on Deciduous Dentition with Anterior Crossbite: Finite-Elements Study

Objective This study aimed to evaluate the influence of three different inclinations of the incisal edge of Planas direct tracks (PDTs) on the upper deciduous incisors (15, 30, and 45 degrees) through simulations using the finite-elements method. Materials and Methods A three-dimensional virtual model of tooth 51 was elaborated by using the Rhinoceros computer-aided design (CAD) software. A mesh was constructed by using the Patran software, and the evaluations were processed by using the ANSYS 15.0 software. The geometry of the elements used consisted of a triangular-base tetrahedron composed of 2,167,386 elements and 3,012,995 nodal points. Results Progressive alterations of proportional intensity and distribution were seen in the areas of tension on the dentoalveolar structures, with increasing inclination of the edge of the PDT. The tractive contact tensions were seen to be concentrated in the vestibular apical thirds and palatine cervical thirds, while the compressive contact tensions were in the palatine apical thirds and vestibular cervical thirds. Conclusion It was concluded that a 30-degree inclination for the PDT was most appropriate for the cases of anterior crossbite in the deciduous dentition. Nevertheless, because this was a laboratory evaluation, clinical criteria and complementary examinations for each case need to be taken into consideration in making therapeutic decisions.

Andy’s Facial Growth Indicator

Facial growth indicator line was originally developed by Dr John RC Mew. Dr Mew discloses a facial growth indicator in his textbook, Bioblock Therapy published in Great Britain by Dr Mew. The indicator line—this is defined as the distance from the tip of the nose to the incisal edge of the lowest upper central incisor. Andy’s facial growth indicator is a modification of facial growth indicator, which was originally developed by Dr Mew.

Central incisors shape and proportions prevalence in Argentinian university students: by visual assessment and a new standardized method

The aim of this study was to analyze the dimensions of the clinical crown of upper central incisors and the prevalence of tooth shapes by two different protocols. Assessment was performed on each of the 111 dental stone type V maxillae models of students of dentistry from Buenos Aires University [93 females and 18 males, mean age 23.70 (± 2.26) years] The mesial and distal-vestibular angles were defined on each right upper incisor, and the following segments were defined: AB (zenith - incisal edge), CD, EF, GH (apical, middle, and incisal thirds - vestibule - mesial and vestibule-distal angles) and their lengths were determined with a precision caliper. Then, the CD/AB, EF/AB and mean CD-EF/AB ratios were calculated. Shapes were assessed by four independent observers, three of whom evaluated digital images of the models, while the fourth had no access to the images, and determined the shapes using an algorithm developed from the dimensions of the studied segments. Rates and confidence intervals were determined, and Fleiss’ Kappa was calculated to assess the agreement among the evaluators who worked with the images and among all of them. Average incisor length was 10 mm, and widths at CD and EF were 7.35 mm (0.65) and 8.27 mm (0.58), respectively. Regarding shapes, 51.58% (47.90-55.20) of the incisors were identified as square, 18.02% (14.50-21.90) as ovoid and 30.41% (30.00-30.90) as triangular. Fleiss’ Kappa agreement was 0.71 (0.62-0.80). The application of the proposed algorithm provided a considerable level of agreement among the observers. Regarding tooth size, both the average segment length and the proportions were similar to those reported by various authors.

Maximum Mouth Opening Range in Adult Patients Presented at Dental OPD CMH, Lahore

Objective: To determine the maximum mouth opening (MMO) in Pakistani adult population and its possible correlation with sex and age. Design of the Study: It was a cross-sectional study. Study Settings: This study was carried out at Outpatient Department of Dentistry Combined Military Hospital, Lahore from January 2019 to July 2019. Material and Methods: The study involved 894 adults’ patients having 463 males and 431 females patients age in the range of twenty one year to seventy years. The patients were asked maximally open their mouth and keep it open until no further opening of mouth possible. Then with the help of calibrated fiber ruler distance was measured from incisal edge of the upper incisor teeth to the incisal edge of the lower incisor teeth. To check the correlation of mouth opening with age a Pearson correlation analysis was done and significance of the test was checked by applying the independent sample T-test will be applied taking p value of ≤0.05 as statistically significant. A written informed consent was obtained from every patient. Results of the Study: For males mean maximum opening of mouth was observed as 51.4±8.1 mm having its range 38 to 70. Mean maximum opening of mouth for females was observed as 43.1±5.9 mm having age range 37 to 55 mm. In 21 to 30 years age group the opening of mouth was 39.90 ± 5.02 mm for female’s patients and 40.26 ± 5.26 mm for male patients. In 31 to 40 years age group the opening of mouth was 39.54 ± 4.69 mm for females and for female’s patients it was 40.24 ± 4.55 for male patients. In 41 to 50 years age group MMO was 40.24 ± 5.02 mm for females and was 40.97 ± 4.79 mm for males. In age 51 to 60 years age group the equivalent values for males were 41.54 ± 5.49 and for females41.04 ± 5.63 mm. In 61 to 70 years age group the corresponding values for females and males were 40.33 ±5.55 mm and41.25 ± 6.04 respectively. Conclusion: The mean MMO for males was 51.4 ± 8.2 and for females was 43.1 ± 6.7. The opening of the mouth looks to reduce with age. The opening of mouth of females is not as much of the males in the all groups of age. Keywords: Maximum mouth opening (MMO), Age, Sex

Influence of Anterior Guidance on the Inclination of Horizontal Condylar Guidance in Dentulous Subjects - A Clinical Study

BACKGROUND One of the most widely used methods to record horizontal condylar guidance is the use of protrusive interocclusal records. Therefore, this study was done to evaluate the reliability of protrusive interocclusal record with and without the influence of anterior determinant on horizontal condylar guidance among dentulous patients. METHODS Diagnostic impressions of 21 participants were made and casts were poured. Facebow record were obtained and transferred to semi-adjustable articulator. Protrusive interocclusal records were made using Alu-wax. In group 1, protrusive interocclusal records were obtained at incisal edge to edge position (conventional method). In group 2, 3 and 4 protrusive interocclusal records were obtained at a distance of 4 mm, 6 mm and at incisal edge to edge position respectively using a customized flat anterior jig. Programming of the Hanau articulator were done for all the 4 groups. One-way ANOVA test and Pearson’s correlation tests were done to compare and correlate horizontal condylar guidance. RESULTS The mean values obtained for flat anterior jig at incisal edge to edge position, at 4 mm and 6 mm provided good Pearson correlation values for the right (R = 0.773, R = 0.779, R = 0.632) as well as the left side (R = 0.631, R = 0.601, R = 0.545) respectively, on comparison with the conventional incisal edge to edge values. This indicated a positive correlation which was statistically significant. CONCLUSIONS The horizontal condylar guidance is influenced by anterior determinant. Therefore, the reliability of protrusive records is dependent on eliminating the influence of anterior determinant. KEY WORDS Horizontal Condylar Guidance, Anterior Determinant, Protrusive Interocclusal Records

Guiding significance of intraoperative frozen section for range of judging incisal edge of Esophageal Carcinoma

Objective: To explore guiding significance of intraoperative frozen section for judging incisal edge range of esophageal carcinoma. Methods: A retrospective descriptive research design was used to collect the clinical and pathological data of 205 patients with esophageal cancer who were treated in Huaihe Hospital of Henan University from March 2012 to July 2015. Among them, 46 patients’ esophageal margins were made into intraoperative frozen sections. Results: In the 205 cases, nine cases were diagnoses with upper incisal edge cancerization, accounting for 4.39%, and five cases were diagnosed with lower incisal edge cancerization, accounting for 2.4%. There were 14 cases in total, accounting for 6.83%. four cases showed positive residual end of intraoperative frozen section. Conclusion: The cancerous focus residue of incisal edge in esophageal carcinoma is not uncommon. Intraoperative frozen section is helpful to judge the proper excision length of esophageal carcinoma. doi: https://doi.org/10.12669/pjms.37.5.3910 How to cite this:He F, Wang C, Liu W, Shi G. Guiding significance of intraoperative frozen section for range of judging incisal edge of Esophageal Carcinoma. Pak J Med Sci. 2021;37(5):---------. doi: https://doi.org/10.12669/pjms.37.5.3910 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Studying the Degree of Tooth Enamel Mineralization through Raman Spectroscopy in Various Spectral Ranges

In vitro and in vivo methods of Raman spectroscopy have been developed to assess the degree of mineralization of the enamel of different functional groups. This article presents comparative studies that were carried out using scanning Raman microspectroscopy with various sources of laser excitation with wavelengths of 532, 785, and 1064 nm. It is shown that the intensity of Raman scattering of enamel can be a measure of its thickness. The obtained dependence of the Raman scattering intensity on the distance from the incisal edge is in good agreement with the literature data, where two independent methods (computer tomography and electron microscopy) are used to determine the enamel thickness values. The proposed methods can be considered as potential quantitative methods for express diagnostics of the state of tooth enamel in vivo.

Challenges in Managing a Fractured Cement-retained Crown Located at the Aesthetic Zone: A Case Report

Implant prosthesis is a popular treatment modality but it is not complication free. This article discussed the management of a cemented, all-ceramic implant crown in the maxillary anterior region that had veneering ceramic fracture after three years in function. A screw-retained prosthesis was prescribed to avoid the show of the screw access channel on the incisal edge of the crown. This was achieved by changing the location of the screw hole using the angle screw channel that overcame the angulation issue.