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A probability distribution of shape for the dental maxillary arch using digital images

Rijal OM, Abdullah NA, Isa ZM, Noor NM, Tawfiq OF

Annu Int Conf IEEE Eng Med Biol Soc, 2012;2012:5420-3.

PMID: 23367155 DOI: 10.1109/EMBC.2012.6347220

Selected landmarks from each of 47 maxillary dental casts were used to define a Cartesian-coordinate system from which the positions of selected teeth were determined on standardized digital images. The position of the i-th tooth was defined by a line of length (l(i)) joining the tooth to the origin, and the angle (θ(i)) of this line to the horizontal Cartesian axis. Four teeth, the central incisor, lateral incisor, canine and first molar were selected and their position were collectively used to represent the shape of the dental arch. A pilot study using clustering and principal component analysis strongly suggest the existence of 3 groups of arch shape. In this study, the homogeneity of the 3 groups was further investigated and confirmed by the Dunn and Davies-Bouldein validity indices. This is followed by an investigation of the probability distribution of these 3 groups. The main result of this study suggests 3 groups of multivariate (MV) normal distribution. The MV normal probability distribution of these groups may be used in further studies to investigate the issues of variation of arch shape, which is fundamental to the practice of prosthodontics and orthodontics.

Matched MeSH terms: Maxilla/anatomy & histology*

Fulltext Cone beam computed tomography assessment of the maxillary incisive canal and foramen: considerations of anatomical variations when placing immediate implants

Al-Amery SM, Nambiar P, Jamaludin M, John J, Ngeow WC

PLoS One, 2015;10(2):e0117251.

PMID: 25679505 DOI: 10.1371/journal.pone.0117251

The maxillary incisive canal connects the roof of the oral cavity with the floor of nasal cavity and has the incisive and nasal foramina respectively at its two opposite ends. Its close proximity with the anterior incisors affects one's ability to place immediate implants in ideal position.

Matched MeSH terms: Maxilla/anatomy & histology*

Maxillae and mandibles of male mosquitoes and female autogenous mosquitoes (Diptera: Culicidae)

Wahid I, Sunahara T, Mogi M

J Med Entomol, 2003 Mar;40(2):150-8.

PMID: 12693842

Maxillae and mandibles of males of 44 species of 12 mosquito genera and females of three autogenous genera and two partially autogenous species were examined under light microscopy and scanning electron microscopy. The maxillae and mandibles of male mosquitoes are delicate, tape-like structures with lengths characterizing genera or higher level classification units. Five patterns are recognized: (A) long maxillae and mandibles with mandibles longer than maxillae in Anopheles; (B) long maxillae and mandibles with maxillae longer than mandibles in Toxorhynchites; (C) short or intermediate lengths of maxillae with short mandibles in Aedes, Armigeres, Culex, Ochlerotatus, Orthopodomyia, and Uranotaenia; (D) short or intermediate length of maxillae with no mandibles in Mimomyia and Tripteroides; and (E) no maxillae and mandibles in Malaya and Topomyia. Maxillary and mandibular lengths of male mosquitoes show a positive correlation. Length of maxillae and mandibles of autogenous females are reduced to the same level as conspecific males. In contrast, females of partially autogenous species have complete maxillae and mandibles as in females of anautogenous species.

Matched MeSH terms: Maxilla/anatomy & histology

Fulltext Evaluation of dental arch dimensions in 12 year-old Vietnamese children - A cross-sectional study of 4565 subjects

Dung TM, Ngoc VTN, Hiep NH, Khoi TD, Xiem VV, Chu-Dinh T, et al.

Sci Rep, 2019 02 28;9(1):3101.

PMID: 30816230 DOI: 10.1038/s41598-019-39710-4

This study aimed to define the width and length of the dental arch in 12-year-old Vietnamese children, and to elucidate differences between genders and among ethnic groups. A cross-sectional study was conducted in 4565 12 years-old children from the 4 major ethnic groups in Vietnam (Kinh, Muong, Thai, and Tay), with a healthy and full set of 28 permanent teeth that had never had any orthodontic treatment and with no reconstructive materials at the measured points. The mean variables in all subjects were 36.39 mm for upper inter-canine width; 46.88 mm for upper inter-first molar width; 59.43 mm for upper inter-second molar width; 10.41 mm for upper anterior length; 32.15 mm for upper posterior length 1; 45.52 mm for upper posterior length 2; 28.31 mm for lower inter-canine width; 41.63 mm for lower inter-first molar width; 54.57 mm for lower inter-second molar width (LM2W); 7.06 mm for lower anterior length (LAL); 26.87 mm for lower posterior length 1 (LP1L); and 41.29 mm for lower posterior length 2. Significant differences in these parameters between genders were found in all ethnic groups, except for LAL in the Kinh and Thai groups, and LP1L in the Tay group. Significant ethnic differences were also found in almost all parameters except LM2W in both males and females. Taken together, the representative sizes of dental arches of 12-year-old Vietnamese children have been defined. Our data indicate that there are some variations in dental arch dimensions among ethnic groups and between genders.

Matched MeSH terms: Maxilla/anatomy & histology

Human evaluation in association to the mathematical analysis of arch forms: Two-dimensional study

Zabidin N, Mohamed AM, Zaharim A, Marizan Nor M, Rosli TI

Int Orthod, 2018 03;16(1):133-143.

PMID: 29478934 DOI: 10.1016/j.ortho.2018.01.009

OBJECTIVES: To evaluate the relationship between human evaluation of the dental-arch form, to complete a mathematical analysis via two different methods in quantifying the arch form, and to establish agreement with the fourth-order polynomial equation.

MATERIALS AND METHODS: This study included 64 sets of digitised maxilla and mandible dental casts obtained from a sample of dental arch with normal occlusion. For human evaluation, a convenient sample of orthodontic practitioners ranked the photo images of dental cast from the most tapered to the less tapered (square). In the mathematical analysis, dental arches were interpolated using the fourth-order polynomial equation with millimetric acetate paper and AutoCAD software. Finally, the relations between human evaluation and mathematical objective analyses were evaluated.

RESULTS: Human evaluations were found to be generally in agreement, but only at the extremes of tapered and square arch forms; this indicated general human error and observer bias. The two methods used to plot the arch form were comparable.

CONCLUSION: The use of fourth-order polynomial equation may be facilitative in obtaining a smooth curve, which can produce a template for individual arch that represents all potential tooth positions for the dental arch.

Matched MeSH terms: Maxilla/anatomy & histology

The application and correlation of Pont's Index to the facial framework of three main ethnic groups in Malaysia

Purmal K, Alam MK, Moganadass DD, Zakariat NN, Cheong NW

Aust Orthod J, 2013 May;29(1):34-42.

PMID: 23785936

To assess the applicability of Pont's Index in a Malaysian population by obtaining baseline measurements of dental arch shape based on premolar arch width, molar arch width and the combined width of the maxillary incisors. A secondary aim was to determine whether a correlation exists between arch widths, Pont's Index and the facial framework.

Matched MeSH terms: Maxilla/anatomy & histology*

Relationship of maxillary incisors in complete dentures to the incisive papilla

Isa ZM, Abdulhadi LM

J Oral Sci, 2012;54(2):159-63.

PMID: 22790408

We investigated the relationship of the maxillary central incisors to the incisive papilla in wearers of complete dentures. First, image analyzer software was used to examine the relationship of the midpoint of the incisive papilla to the labial surface of the maxillary central incisors on occlusal photographs of 120 maxillary casts from dentate Malaysian adults. Then, an Alma denture gauge was used to identify the position of the labial surface of the maxillary central incisors in relation to the midpoint of the incisive papilla in complete dentures from 51 patients who requested replacement dentures at the Faculty of Dentistry, University of Malaya. The mean incisor distance to the incisive papilla in dentate adults was 9.59 ± 1.00 mm, while the mean incisor distance to the incisive papilla in complete dentures was 6.34 ± 1.87 mm. Thus, in our sample of edentulous patients, the anterior teeth in complete dentures were positioned approximately 3 mm closer to the incisive papilla, as compared with the position of the central incisors in natural dentition, and did not duplicate the position of the natural anterior teeth.

Matched MeSH terms: Maxilla/anatomy & histology*

Tooth size and dental arch dimensions: a stereophotogrammetric study in Southeast Asian Malays

Al-Khatib AR, Rajion ZA, Masudi SM, Hassan R, Anderson PJ, Townsend GC

Orthod Craniofac Res, 2011 Nov;14(4):243-53.

PMID: 22008304 DOI: 10.1111/j.1601-6343.2011.01529.x

To investigate tooth size and dental arch dimensions in Malays using a stereophotogrammetric system.

Matched MeSH terms: Maxilla/anatomy & histology

Maxillary arch and central incisor dimensions of an ethnic Chinese population in relation to complete denture prosthodontics

Keng SB, Foong KW

Int Dent J, 1996 Apr;46(2):103-7.

PMID: 8930682

In the absence of pre-extraction records, investigators have used various methods to aid in the selection and placement of artificial teeth for complete dentures. Natural tooth position and size provide the dentist with an optimal guide. A study was conducted on a group of ethnic Chinese subjects where direct measurements were made of the arch size and width of the maxillary central incisor on stone casts. The anterior arch width represented by the inter-canine cusp tip distance was 35.74 +/- 2.17mm. The mesiodistal diameter of the maxillary central incisor was 8.85 +/- 0.59mm with a range of 7.60mm to 11.20mm. The results of this study was discussed against other findings on the Caucasian, Nigerian and Malay groups. The significance of artificial tooth selection for dentures was highlighted in relation to the results obtained from the study for the group of Chinese and other races.

Matched MeSH terms: Maxilla/anatomy & histology*

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