Year : 2006 | Volume
: 24 | Issue : 4 | Page : 192--196
Mesiodistal crown dimensions of the permanent dentition in North Indian children
SP Singh1, A Goyal2,
1 Unit of Orthodontics, Oral Health Sciences Center,PGIMER, Chandigarh, India
2 Unit of Pedodontics and Preventive Dentistry, Oral Health Sciences Center, PGIMER, Chandigarh, India
S P Singh
Unit of Orthodontics, Oral Health Sciences Center, PGIMER, Chandigarh
This investigation was conducted on 110 individuals, (40 males and 70 females) in the age range of 12-18 years. The results revealed the mesiodistal crown dimensions of teeth of males to be more than that of the females. Further the ratio of the mesiodistal crown dimension of the maxillary lateral incisors to the maxillary central incisors was 80% in females and 78% in males. The total arch length in males was 117.77 mm in maxilla and 111.60 mm in mandible, while in females, the figures were 113.98 mm in maxilla and 107.10 mm in the mandible.
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Singh S P, Goyal A. Mesiodistal crown dimensions of the permanent dentition in North Indian children.J Indian Soc Pedod Prev Dent 2006;24:192-196
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Singh S P, Goyal A. Mesiodistal crown dimensions of the permanent dentition in North Indian children. J Indian Soc Pedod Prev Dent [serial online] 2006 [cited 2020 Nov 24 ];24:192-196
Available from: https://www.jisppd.com/text.asp?2006/24/4/192/28076
The task of an orthodontist is to align the teeth to improve the masticatory efficiency, facial esthetics and alignment of the dental arches, which becomes frustrating in the presence of crown-size discrepancies.,, It is essential for the clinician to know the size of individual tooth and groups of teeth, to make an adequate diagnosis and treatment plan.,,
The Orthodontic examination may be incomplete without a careful analysis of the patterns of mesiodistal crown size relationships, hence to improve the quality of available dental care, there is an urgent need for baseline data on the sizes of individual teeth.
Indications on mesiodistal dimensions are available on crown dimensions of the teeth of American Caucasians,, and their ethnic groups.,,, The determination of ratios, indicative of how large the maxillary teeth are, have been suggested to be in relation to their lower counterparts,, or to ratios which presumably indicate the correct amount of over-jet or overbite.,,,
Richardson et al. found teeth of males to be larger than those of females for each type of tooth in both the arches. Sanin and Savara reported differences in crown size patterns even among good occlusion cases. Howe et al. in their study found combined mesiodistal width for males to be more as compared to females. Smith et al. in their study on incisor shapes and crowding found males to have slightly larger average teeth dimensions than females. Further Moorrees in his study on 184 North American white children reported that males to have wider teeth mesiodistally than females.
The aim of this study was to establish normative data of the mesiodistal crown dimensions of permanent teeth in Punjabis a state of Northern India. This is a part of a more comprehensive study being carried out on crown measurements.
Materials and Methods
The sample consisted of study casts, both maxillary and mandibular of 40 males with age range of 12-18 years (15+2.16 years) and 70 females with age range of 12-15 years (13.5+1.16 years) belonging to the city of Ludhiana (Punjab). The sample was selected from amongst patients reporting to the Department of Orthodontics, Christian Dental College, Ludhiana seeking treatment for malocclusion and general check up, having full complement of teeth.
Impressions were made of the selected sample using irreversible hydrocolloid (alginate) impression material of both maxillary and mandibular arches. Impressions material, which were poured immediately in green dental stone. The study models thus prepared were finished and polished. A boley's gauge with vernier scale to read value of nearest up to 0.1 mm was used to measure the tooth size. The tips of the caliper were grounded to a point in order to facilitate the greatest degree of accuracy. The mesiodistal dimensions were obtained by measuring the maximum distance between the two sides of the tooth on a line parallel to occlusal and buccal surfaces. Care was taken to include only fully erupted permanent teeth on both sides of the dental arches up to the second molars. Third molars were however excluded. The exclusion criteria involved any obvious loss of tooth material mesiodistally because of caries, fracture or excessive proximal wear, mesial or distal restorations of any kind, congenital defects and deformed teeth.
The data was subjected to statistical evaluation. The ratios of mean mesiodistal dimensions of various types of teeth was computed. This included the ratio of tooth sizes within the same arch as well as the ratio of the tooth sizes of mandibular to maxillary teeth. The Bolton index was used to calculate the ratio between the teeth in the same arch which was computed as:
X1 = Mesiodistal crown dimension of smaller tooth.
X = Mesiodistal crown dimension of larger tooth.
The ratio between the maxillary incisors was computed as follows:
Mean mesiodistal crown size of maxillary lateral incisors
Mean mesiodistal crown size of maxillary central incisor.
The ratio between the groups of teeth, arch segment and arches was calculated using with the same formula.
X1 = Sum of mean mesiodistal dimensions of mandibular teeth.
X = Sum of mean mesiodistal dimensions of maxillary teeth.
Mean mesiodistal crown dimension of mandibular anterior teeth
Mean mesiodistal crown dimension of maxillary anterior teeth
Ratio between total maxillary and mandibular teeth was calculated as:
Mean mesiodistal crown dimension of all mandibular teeth
Mean mesiodistal crown dimension of all maxillary teeth
Mean mesiodistal crown dimension of teeth
The mesiodistal crown dimension of teeth for males and females in both the arches is given in [Table 1]. The mean mesiodistal crown dimension of the permanent dentition of the males was found to be larger than the females for each type of tooth in the maxillary and mandibular arches [Figure 1][Figure 2]. Both males and females exhibited a similar pattern of tooth size [Figure 3][Figure 4]. In the maxillary arch, the mean width of the crowns of the central incisors (9.05 mm in males and 8.62 mm in females) was larger than the mean width of the crowns of the lateral incisors (7.07 mm in males and 6.95 mm in females). The mean width of the mesiodistal dimension of the first premolars was larger (7.35 mm in males and 7.20 mm in females) than that of the second premolars (7.10 mm in males and 6.76 mm in females) and the mean width of the mesiodistal dimension of the first molar was larger (10.35 mm in males and 10.03 mm in females) than that of the second molar (9.95 mm in males and 9.57 mm in females). In the mandibular arch the mean width of the mesiodistal dimension of the central incisors was lesser (5.68 mm in males and 5.55 mm in females) than that of the lateral incisors (6.31 mm in males and 5.98 mm in females) [Figure 1][Figure 2], [Table 1]. The mean width of the mesiodistal dimension of first premolar was less (7.42 mm in males and 7.02 mm in females) than that of the second premolars (7.55 mm in males and 7.17 mm in females) and mean mesiodistal dimension of the first molar (11.23 mm in males and 10.81 mm in females) was larger than that of the second molar (10.33 mm in males and 10.01 mm in females).
Ratio of tooth sizes expressed in percentage
The ratio of the mean mesiodistal crown dimension of the maxillary lateral incisor to that of the maxillary central incisor was approximately 79%, the figures being was 80% in females and 78% in males. In the mandibular arch the ratio of the mean of mesiodistal dimension of the central incisor to that of the lateral incisor was 92% in females and 90% in males. The ratio of the maxillary second premolar to the first premolar was 93% in females and 96% in males. In the mandibular arch, the ratio of the mesiodistal dimension of the first and second premolar was 96% in females and 92% in males. Further, the ratio of the maxillary second molar to the first molar was 95% in females and 92% in males. In the mandibular arch, the ratio between the first molar and the second molar was 92% in both females and males [Table 2].
Ratio expressed in percentage of arch length and arch segments of the mandible and maxilla
The mean total arch length (total mesiodistal tooth material from the distal aspect of the right second molar to the distal aspect of left second molar) was 113.98 mm in the maxilla and 106.82 mm in the mandible in females. In males the mean total arch length was 118.06 mm in maxilla and 111.56 mm in the mandible [Table 1].
The ratio of the mean width of the mandibular dentition to the mean width of the maxillary dentition was 97% in both males and females. The ratio of the sum of the mean widths of the canines and incisors of the mandible to those of the canines and the incisors of maxilla was 78% in both sexes.
Dunn and Dobzhansky have indicated that all men belong to a single species, but men inhabiting different parts of the world are not alike. As compared to other ethnic groups, no measurements of tooth sizes have been made on the Punjabis. This study was conducted to provide normative data on the mesiodistal crown measurements. The results of this study agree with those of a smaller sample reported by Richardson and Malhotra that the first molars were larger than the second molars in both maxillary and mandibular arches in the both the sexes.
The results of Verma and Kapoor on twins are almost compatible, relative to the absolute size of the teeth. There is a great disagreement in the literature regarding the relative sizes of the first and second molars. The results of the present study are contrary to that the maxillary first premolars are larger than the maxillary second premolars and the maxillary first molars are larger than the second molars. In the mandibular arch the second premolars were found to be larger than the first premolars and the first molars were larger than the second molars. These results do not agree with the findings Moss. In the literature, a possible reason for the difference, it is possible that Moss and Verma and Kapoor's approach to the problem could have been influenced by: a small sample size, the fact that they used extracted teeth which were less in number than the complete set of teeth available from each individual.
The mandibular incisors showed less variability in size than the maxillary incisors. In the remaining teeth there was greater variability in the mandibular teeth than in the maxillary teeth. The greatest variability was seen in the size of mandibular second molars in males as well as females. The mandibular central incisors showed the least variability of all the teeth in both sexes as is evident in [Table 1]. This finding is in agreement with other studies.,,
It is imperative to emphasize the ratio of the mean width of the maxillary canine and incisor teeth to the mean width of the mandibular canine and incisor teeth as well as the ratio of the mean width of the maxillary incisors to the mean width of the mandibular incisors orthodontic therapy for cosmetic purpose makes this relationship a matter of prime concern if one is to provide acceptable therapy.
The importance of tooth measurement and its application in diagnosis and clinical dentistry has been well emphasized in the past.,, Some of the more common types of malocclusion are basically due to discrepancy between tooth material and size of the dental arches. This discrepancy may be reflected clinically as crowding of the teeth, if a combination of excessive tooth material and a short dental arch length exists. On the other hand, it may result in spacing and diastema between the teeth if the arch length is more and teeth material is less. In either case, it is the space problem, which is of great interest to the general dentist, as well as to the pedodontist and orthodontist in diagnosis and treatment planning. The tooth size ratio also contributes a great deal to balanced occlusion, facial harmony and esthetics.
Summary and Conclusion
A study of the mesiodistal crown dimensions was conducted on the teeth of 110 North Indian children (forty were males and seventy were females) who reported to seek orthodontic treatment in the Christian Dental College, Ludhiana. The mesiodistal crown dimensions of the teeth were measured from plaster casts by means of a Boley's gauge. The results revealed the mesiodistal crown dimensions of teeth of males to be larger than those of females for each type of tooth in both arches, although they exhibited a similar pattern of tooth size. The maxillary first premolars were larger than the second premolars, whereas the mandibular second premolars were larger than the first premolars. The first molars were larger than the second molars in both maxillary and mandibular arches in both sexes. The ratio of the mandibular dentition to the maxillary dentition was 94% in both the sexes. The ratio of the sum of the widths of the canines and incisors of the mandibular dentition to those of the maxillary dentition was 78% in both the sexes. The ratio of the widths of the mandibular incisors to the maxillary incisors was 96.53%.
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