Posted at 10.13.2018
Title: Relationship of the maxillary central incisor teeth form with face form and gender in a portion of the North Indian people - An AutoCAD analysis
Aim: An esthetically satisfying repair or prosthesis should not be identifiable as unnatural, but should maintain harmony with the natural tooth arrangement of an individual. This study aimed to determine whether a correlation exists between your maxillary central incisor tooth form and the cosmetic form and gender of subjects in a selected sample of the North Indian inhabitants. Materials and Methods: The study was conducted in the Team of Prosthodontics and Crown and Bridge and Implants, Manav Rachna Teeth College or university, Faridabad. Two standardized photos each (family portrait [closed mouth] and teeth in occlusion [with cheek retractor]) of 200 subjects of North Indian origin (a long time 18-25 years) their studies at Manav Rachna International School were assessed for facial form and teeth form, using the AutoCAD (Autodesk Inc. 2013, California, USA) software. Results and Conclusion: A statistically significant relationship of the maxillary central incisor tooth form with the inverted face form of the topic was found in a section of the North Indian inhabitants. However, the relationship between your maxillary central incisor teeth form and gender of an individual was found to be statistically insignificant.
Keywords: Maxillary central incisor, tooth form, face form, gender, AutoCAD
Esthetic dentistry is fast learning to be a key awareness for dentists and their patients. Although, a teeth is seen as a numerous factors relating both the pearly whites and surrounding soft tissues, the esthetic appearance of the anterior teeth plays a part in a person's self-confidence and exactly how attractive he/she is identified by others. 1 For an esthetically satisfying smile, the positioning, form and colour of the maxillary central incisors will be the most essential factors. 2
Since the maxillary central incisors play an integral role in the dental care composition, various anthropometric and biometric personal references are used in their design and selection in esthetic accordance with the facial form of the patient. 3 When only parts of the dentition need to be restored, the remaining natural dentition can serve as helpful information, providing a relatively simple and immediate procedure to create artificial pearly whites that mix with or go with the natural dentition. However, in cases where all one's teeth are absent and the complete dentition should be restored, no information can be gained from the remaining natural pearly whites, old photos, or solid models, other methods have to be applied to select and design the missing teeth. 1 These procedures are not only useful for complete dentures but also for any complex anterior recovery. 2
Esthetic dentistry attempts to produce a prosthesis that defies recognition. This is possible only once, the teeth form, tone and tooth size of the patient are in maximum harmony with their facial form, proportions and facial appearance. In 1914, Williams 4 was the first to suggest that a correlation been around between the upside down facial shape and the form of the upper central incisors. Form form had become guided in comparison with the inverted condition of the facial skin. According to the classification, the oral outlines of the upper incisors were in three forms: tapered, ovoid and square, which is still considered by prosthodontists. 5 In 1955, Frush and Fisher6 launched the idea of dentogenics or the dentogenic theory which explained that the correct tooth form should be designed or preferred in regards to to the patient's sex/gender, personality and age group (SPA factor).
The prosthodontics literature pertains generally to the non-Indian population and there is a lack of information on the selection and design of artificial anterior tooth forms in the Indian population. The data of racial norms for facial appearance might aid practitioners, because the treatment given would be in tranquility with the facial appearance for patients of different races.
Most studies, 7, 8, 9 on the main topic of artificial pearly whites design and selection, with respect to facial form and gender, have been predicated on subjective evaluation and assessments of different individuals; with insufficient standardized methods and techniques and unavailability of technical resources. Hence, their reliability has been questionable. This study tries to boost the exactness of the technique by employing a software known as AutoCAD (Autodesk Inc. 2013, California USA) - Automobile Computer Aided Design and Drafting. AutoCAD is a 2-D and 3-D, vector based, computer-aided drafting software application used in structures, construction and production to aid in the preparation of plans and other anatomist plans. 10 This high end technology has been applied to make the process of analyzing the maxillary central incisor teeth form, easier, objective plus more accurate.
The present review aims to examine whether a correlation exists between the maxillary central incisor tooth form and face form of the subject and to evaluate if any gender distinctions could be observed with regards to the form of the maxillary central incisor. The null hypothesis of the study is that there are no gender specific dissimilarities in teeth form as well as no relationship between facial form and teeth form of a person.
Materials and Methods
A total of 200 dentulous topics of North Indian origins (a long time 18-25 years) studying at Manav Rachna International University or college, with well aligned natural maxillary anterior tooth were randomly determined. The things being young adults belonging to various areas of North India shaped an appropriate representative sample.
Each subject matter was interviewed, to verify the inclusion requirements and to rule out the exclusion standards.
The exclusion conditions were: topics with anterior teeth fractures, things having maxillary anterior tooth with considerable carious lesions, themes with incisal wear of maxillary anterior teeth, topics with gingival hyperplasia in the maxillary anterior teeth, subjects who've been through orthognathic surgery, orthodontic treatment, and those with congenital or surgical facial defects, people that have microdontia or macrodontia and topics with any type of prosthetic restoration on their anterior pearly whites. A participant prepared consent form (PICF) was provided in both british and hindi dialects. The educated consent form was explained to each participant and was authorized by them prior to starting the procedure.
A standardized photographic treatment was used to obtain images of the facial skin and the maxillary central incisors. Each subject matter was made to sit upright on the seat with the occlusal plane of the maxillary tooth parallel to the floor. Two standardized photographs were taken for every single subject: family portrait (closed mouth) and the maxillary incisors (without mouth). For every photograph, standardized ranges (family portrait - 100cms, teeth- 12cms) were used (from the end of the subject's nose area to the centre of the camera zoom lens). A set focus of 1 1:1 was used for each and every subject, with theEF 100 mmf/2. 8 Macro USM zoom lens. The elevation of the Canon EOS 1100D DSLR camera mounted on a tripod (Traveller Minuscule Pro Tripod For Cannon EOS 1100D) was adjusted individually according to the position of the subject's face and teeth. A full face photograph with closed lip area was obtained, with zoom lens positioned parallel to subject face. The subject's wild hair didn't cover any area of the face and the teeth were connected [Number 1]. The standardized photographic process was followed according to the sooner method accompanied by Wolfart S et al. 2 Intraoral photographs of maxillary central incisors were obtained before zoom lens was parallel to the labial surface of the teeth. Cheek retractors were used to obtain full subjection of the maxillary central incisors. The maxillary incisors were centred in the photograph, with the midline centred and perpendicular to the incisal airplane [Number 2]. Utilizing the image editing and enhancing software (Adobe Photoshop 8. 0. 1, Adobe systems, San Jose, California), the images were adjusted so that the maxillary incisors stay centred in the image, individually, with the long axis arranged vertically. [Body 3].
The mathematical analysis of the images was done in line with the methodology suggested by Wolfart et al 2.
The outline of the upper right incisor was followed and in the next step, the median of the teeth was used the sketch. (X) was the most apical point of intersection between your median and the format. Mesial and distal tangents were designed to the outline - parallel to the median. Two perpendiculars were drawn on the median starting from the most apical (O1) & most incisal (O2) point of intersection between the format and the tangent. They define two factors of intersection (S1 and S2). The collection S1S2 was bisected (S). By taking the width of the teeth through (S) the widest stretch out across the tooth was identified (TB). Dividing the brand SX into five parts, the range TA could be produced parallel to TB on 4/5 of the space of XS. The outline sketch was flipped upside down for the analysis of the facial skin shape. The lines FB (the widest stretch over the face) and FA (a defined parallel stretch to range FB) were constructed in an analogous manner to the lines TA and TB. [Body 4]. For the analysis of the face shape, the put together sketch of the portraits was turned upside down. The facial put together form was dependant on the format of the temporal bone at the elevation of the hairline, temporal process of the zygomatic arch and the gonion. The facial quotient (FQ) was computed within an analogous manner to that of the teeth quotient (TQ) [Shape 5]. Based on the numerical values that were obtained, oral and facial forms were classified as: 
- Tapered (‰ 0. 61)
- Oval (‰Ґ0. 61 and ‰ 0. 70)
- Rectangular (‰Ґ 0. 70)
The data, for each and every subject were documented in a standardized proforma, along with the photographs of the subject before and after analysis.
The data obtained were set up systematically and transferred to Statisticals Package deal for the Social Sciences (SPSS) version 20, IBM Inc. for examination. The next statistical methods were applied: descriptive statistical tests, chi square tests, 3rd party t-tests and Spearman relationship. The level of statistical relevance was place at p-value ‰ 0. 05.
Chi-square test was used for evaluation between categorical variables. Student's 't' test was used for checking two groups with respect to continuous and normally distributed variables.
The design and selection of maxillary anterior tooth for esthetically pleasing prosthetic rehabilitation has long posed challenging in medical practice. A reliable and reproducible method is necessary for prosthetically rebuilding anterior pearly whites in terms of these size and form, that happen to be compared to the facial skin and gender of the patient.
Our first aim was to look for the maxillary incisor teeth form of each subject using the AutoCAD software. The analysis was then categorised into three varieties - ovoid, rectangular and tapering. The oval category was the most widespread tooth form among the analysis population while the square tooth form was the least prevalent. These findings were in accordance with the study by Brunetto et al 11 on a Brazilian population. However, in a report conducted by Wolfart et al 2 on the German population, even though oval group of tooth form was most prevalent, the least prevalent tooth form seen was the tapered form. These distinctions may be credited to ethnic and genetic populace variability and better software accuracy, followed in today's study.
Our second purpose of the analysis was to determine whether a relationship existed between the maxillary central incisor tooth form and the facial skin form. Since this finding is statistically significant in today's study test, therefore, the null hypothesis of the study, was rejected. This is in accordance with the results of tests by Selg 12 and Sellen et al 3 which postulated that the face form of a patient was helpful in selecting the manufactured tooth form for his or her prosthesis. Our results also established William's "law of tranquility" which suggests that a relationship exists between your inverted facial form and the form of the maxillary central incisors. 4 Some studies 5 and books reviews 3, 13 concur that even despite controversies surrounding the authenticity of William's legislations of harmony, it continues to be the easiest, the most readily useful and the most predictable method of artificial tooth selection for anterior tooth. On the other hand, the validity of William's classification has been questioned by various creators. 14, 2, 15, 16, 8, 17, 18 The positive relationship seen between tooth form and face form in this study as compared to statistically insignificant results obtained in a variety of earlier studies 2 can be attributed to the utilization of a far more practical, technically advanced and exact AutoCAD (Autodesk Inc. 2013, California USA) software which enhanced the exactness and reliability of the examination. Past studies were generally based on visual and subjective perseverance of the tooth and face varieties and hence did not provide valid results. The hereditary variability of different populations, on which previous studies have been conducted, could also have some affect on the ultimate results.
Our third objective was to determine whether a correlation existed between your tooth size and the gender of an person. This correlation was found to be statistically significant. The size of the maxillary central incisor in men was found to be bigger than that of women. That is in accordance with studies which concluded that tooth size is known to correlate with gender. 1, 19, 20, 21
Our fourth goal was to determine whether there is a correlation between the teeth form and the gender of the person. This correlation was found to be statistically insignificant. This end result was in agreement get back of Wolfart et al 2 and Berksun et al 16 who noted no significant dissimilarities in tooth form between the genders. However, Horvath et al 1 and Brunetto et al 11, reported that maxillary anterior tooth do have gender specific distinctions and that teeth styles are gender specific. Inside our research, the oval tooth form was found to be the most prevalent in both genders. This was like the results obtained by Brodbelt et al 22 and Wolfart et al 2. Hence, choosing the oval form has a better chance of corresponding the original tooth, regardless of the gender. A higher ratio of the rectangular teeth form was observed in women as compared to men. This result was also similar compared to that of Wolfart et al 4 and Brunetto et al. 11 This finding shows that opting for a square teeth form for a male patient is statistically much more likely to bring about a mismatch. Hence, the dentogenic concept that suggests that the female pearly whites should become more round and the male pearly whites should become more squarish is not reinforced by the results of this study.
Within the constraints of this research, it was discovered that in a section of the North Indian people that: