Spacing in deciduous dentition of Polish children in relation to tooth size and dental arch dimensions

Aim

To assess the prevalence of primary and secondary spacing in the deciduous dentition and its correlation to tooth widths and dental arch dimensions.

Subjects and methods

Dental casts of 50 preschool children free from malocclusion, were analysed. The width of each space was measured as the smallest distance between the proximal surfaces of the neighbouring teeth, parallel to the occlusal plane. Crown width was measured as the greatest distance between the mesial and distal surfaces of the crown, parallel to the occlusal plane. Intercanine widths were measured between cusp tips of upper and lower canines. Intermolar widths were measured between the central fossae of the second molars. Arch lengths were measured from the midpoint between the central incisors to the midpoint between the distal surfaces of the deciduous second molars.

Results

The primary spaces were present in the upper dental arch in 90% children, on the average 2.09 mm in maxilla and 1.25 mm in mandible. Their widths were dependent on upper intercanine width. Secondary spacing was present in 92% children in the upper dental arch (mean 2.86 mm) and 90% in the lower (mean 3.08 mm). Lower secondary spacing was correlated to lower intercanine width and lower arch length. Total absence of interdental spacing was found in 4% children.

Conclusions

Interdental spacing of the deciduous dentition is present in 96% of Polish children. Children with wider intercanine widths have wider primary spaces in maxilla and wider secondary spaces in mandible.     

Secular changes in tooth size and dental arch dimensions in the mixed dentition

Secular changes in the mixed dentition were studied. Permanent tooth size and dental arch dimensions were examined in Norwegian children born in the 1960s and 1980s, Swedish children born in the 1960s and 1980s, Norwegian Sami children born in the 1980s, and a sample of Norwegian skulls dating from the 14th to the 19th century. The Norwegian Sami children were nomadic in the summertime. A sample of pigs was studied before and after a maceration process to determine what dimensional changes might occur in such a process. A shrinkage of 0.3%-1.7% was found. This information was used when the skulls were compared with the modern groups. Lateral dental arch lengths were shorter in the children born in the 1960s compared with the children born in the 1980s. This was a result of the higher prevalence of caries in the second deciduous molars in the 1960s groups. Children who had lost a deciduous canine prematurely were found to have smaller dental arch perimeters. When compared with other data, this was blamed on a pre-existing crowding. Permanent tooth size was smaller in the skulls compared with the modern groups. Improved nutrition is considered to be the main reason for the difference. Relative dental arch space differed in the group born in the 1960s from that in the other groups, indicating a greater prevalence of crowding in the former. Relative dental arch space in the skulls and in the group born in the 1980s was similar. A more traditional way of living, as practised by the Sami group in this thesis, was not favorable for relative dental arch space. The transverse intermaxillary relation in boys changed from the 1960s to the 1980s, which indicated that the 1980s group ran a greater risk of developing a posterior cross-bite. Before the same conclusion could be made in the girls, the mesial drift of the first permanent molars had to be corrected for, because of a higher prevalence of caries in the 1960s group. The sex-pooled analysis of the skulls and the contemporary groups revealed that the risk for developing a posterior cross-bite in the 1980s group was greater than in the skulls. The skulls had smaller arch depths than the modern groups.     

Stability of dental arch expansion in the deciduous dentition

Thirteen patients with deciduous dentition and more than 3mm intercuspid arch length deficiency are expanded and followed, with controls, for 6 years. Arch perimeter and width at permanent cuspids and bicuspids appear to be slightly greater, and lower incisors are positioned somewhat more forward on the mandible.     

The diastemas in deciduous dentition: the relationship to the tooth size and the dental arches dimensions.

Tooth size and different arch parameters were studied for influence in the presence or absence of diastemas in the primary dentition. The size of teeth scarcely influences the presence or absence of diastemas, but the dental arch dimensions are closely connected with diastemas.     

Innervation of human tooth pulp in relation to caries and dentition type

The neural status of carious teeth, particularly those associated with a painful pulpitis, is largely unknown. This study sought to determine differences in the innervation density of human primary and permanent teeth and whether caries or painful pulpitis was associated with anatomical changes in pulpal innervation. Coronal pulps were removed from 120 primary and permanent molars with a known pain history. Teeth were categorized as intact, moderately carious, or grossly carious. Using indirect immunofluorescence, we labeled sections for the general neuronal marker, protein gene product 9.5. Using image analysis, we found permanent teeth to be significantly more densely innervated than primary teeth. While there was no significant correlation with reported pain experience, neural density in both dentitions increased significantly with caries. Analysis of these data suggests that caries-induced changes in neural density may be functionally more important in the regulation of pulpal inflammation and healing than in the processing and perception of dental pain.     

Gingivitis in the human deciduous dentition

This study examined the relationship between clinical and histomorphometric parameters in the human deciduous dentition. Clinical parameters including plaque index, gingival swelling, gingival color, tooth mobility and degree of root resorption were determined prior to the extraction of teeth. The teeth were extracted with their surrounding gingiva in order to preserve the in situ relationship between the hard and soft tissues. Histomorphometric analysis was carried out on 55 sites, using block surface light microscopy (BSLM). Apical migration of the junctional epithelium was found at 53% (29) of the sites. The gingival sulcus was shallow (0.3 +/- 0.19 mm) and coronal to the cemento-enamel junction at 84% (46) of the sites. Junctional epithelium with retepegs was present at 89% (49) of the sites, whilst an inflammatory cell infiltrate (ICI) was present at all sites examined. The ICI was located opposite to the junctional epithelium and cementum at 80% (44) of the sites. The extent of ICI correlated positively with the patients' age and was significantly increased when clinical evidence of gingival swelling or redness was present.     

A clinical photogrammetric method to measure dental arch dimensions and mesio-distal tooth size

The aim of this research was to evaluate the reliability and validity of measurements obtained from clinical standardized occlusal photographs compared with dental cast measurements. This study comprised a consecutive sample of 16 patients (eight males and eight females, aged 15-24 years) in the permanent dentition without agenesis and/or tooth loss. A paired t-test and intraclass correlation coefficient (ICC) were used to examine validity and reliability. Both statistics were applied for intra- and inter-methods error analysis, at P < 0.05. Random error for the photogrammetric method (less than 0.48 mm) was similar to that for the dental cast measurements (less than 0.43 mm). ICC revealed excellent reliability for both methods (P < 0.01) and no significant difference for any variables, with the exception of upper inter-canine width obtained on the dental casts (P = 0.0038) and photogrammetry (P = 0.01). However, differences were less than 1 per cent of the mean inter-canine width. Inter-method analysis showed a significant correlation for all variables (P < 0.001), with good to excellent reliability (r = 0.66-0.93). A significant mean inter-method difference was consistently observed for the upper first molars (0.33 mm, P < 0.01). For the remaining teeth (left to right second premolars), the largest mean difference was approximately equal to the resolution of the human eye (0.2 mm or less). Minor differences (around 2 per cent of the mean) and an excellent ICC (0.75-0.93, P < 0.01) were observed for arch dimensions. Except for the mesio-distal width of the upper first molars, the recently developed photogrammetric method showed accuracy, validity, and reliability acceptable for clinical and scientific purposes.     

16名中国汉族儿童乳牙列期牙弓和基骨弓研究

目的 研究中国汉族儿童在3～6岁期间乳牙列下颌牙弓和基骨弓的生长发育规律及二者的相关性.方法 在深圳市幼儿园小班(3～4岁)抽取乳牙期汉族儿童75名,连续3年定期追踪,完成检查16名(男孩10名,女孩6名),获得模型48副,进行下颌牙弓及基骨弓生长发育及二者相关性研究.结果 各年龄段牙弓大小差异有统计学意义(P＜0.05),且年龄越大牙弓越大;WC-WC基骨弓大小差异无统计学意义(F=0.71,P=0.556 5),WD-WD和WE-WE基骨弓大小差异有统计学意义(P＜0.05),年龄越大基骨弓越大;各年龄段C/E牙弓比值(F=1.59,P=0.211 8)和C/E基骨弓比值(F=0.34,p=0.795 8)差异无统计学意义.牙弓和基骨弓经Pearson相关性检验,各参数均呈现高度相关性(R＞0.8,P＜0.05).结论 3～6岁乳牙列期中国汉族儿童牙弓和基骨弓大小随着年龄增长而扩大(除了乳尖牙区的基骨弓宽度),但形态上无明显变化,二者形态高度相关.     

An examination of dental crowding and its relationship to tooth size and arch dimension

This investigation was undertaken to examine the extent to which tooth size and jaw size each contribute to dental crowding. Two groups of dental casts were selected on the basis of dental crowding. One group, consisting of 50 pairs of dental casts (18 males and 32 females), exhibited gross dental crowding. A second group, consisting of 54 pairs of dental casts (24 males and 30 females), exhibited little or no crowding. Means and standard deviations of the following parameters were used to compare the two groups: individual and collective mesiodistal tooth diameters, dental arch perimeters, and buccal and lingual dental arch widths. Statistically, the crowded and noncrowded groups could not be distinguished from each other on the basis of mesiodistal tooth diameters. However, significant differences were observed between the dental arch dimensions of the two groups. The crowded group was found to have smaller dental arch dimensions than the noncrowded group. The results of this study suggest that consideration be given to those treatment techniques which increase dental arch length rather than reduce tooth mass.     

Longitudinal dental arch changes in the mixed dentition

The purpose of this study was to investigate dental arch changes that occurred during the mixed dentition in 30 normal occlusion children. Two analyses were done. The first one was at the age of early mixed dentition and the second at the age of late mixed dentition. Most width variables were greater in the males, and depth variables greater in the female subjects. A directionally larger left side of the maxilla and right side of the mandible were observed. Our findings indicate that most arch width dimensions are established in the early mixed dentition. We conclude that the period between the early and late mixed dentition is suitable for environmental factors to disrupt the ideal symmetrical developmental pattern because more growth and developmental changes occur after a relatively stabile period of deciduous dentition.     

Association between breastfeeding duration,non-nutritive sucking habits and dental arch dimensions in deciduous dentition: a cross-sectional study

Background

This cross-sectional retrospective study was conducted to determine association between breastfeeding duration, non-nutritive sucking habits, dental arch transverse diameters, posterior crossbite and anterior open bite in deciduous dentition.

Methods

415 children (228 males and 187 females), 4 to 6 years old, from a mixed Indian population were clinically examined. Based on written questionnaire answered by parents, children were divided into two groups: group 1 (breastfed for <6 months (n = 158)) and group 2 (breastfed for ≥6 months (n = 257)). The associations were analysed using chi-square test (P < 0.05 taken as statistically significant). Odds ratio (OR) was calculated to determine the strength of associations tested. Multivariate logistic regression analysis was done for obtaining independent predictors of posterior crossbite and maxillary and mandibular IMD (Inter-molar distance) and ICD (Inter-canine distance).

Results

Non-nutritive sucking (NNS) was present in 15.18% children (20.3% in group 1 as compared to 12.1% in group 2 (P = 0.024)). The average ICD and IMD in maxilla and average IMD in mandible were significantly higher among group 2 as compared to group 1 (P < 0.01). In mandible, average ICD did not differ significantly between the two groups (P = 0.342). The distribution of anterior open bite did not differ significantly between the two groups (P = 0.865). The distribution of posterior crossbite was significantly different between the two groups (P = 0.001). OR assessment (OR = 1.852) revealed that group 1 had almost twofold higher prevalence of NNS habits than group 2. Multivariate logistic regression analysis revealed that the first group had independently fourfold increased risk of developing crossbite compared to the second group (OR = 4.3). Multivariate linear regression analysis also revealed that age and breastfeeding duration were the most significant determinants of ICD and IMD.

Conclusions

An increased prevalence of NNS in the first group suggests that NNS is a dominant variable in the association between breastfeeding duration and reduced intra-arch transverse diameters which leads to increased prevalence of posterior crossbites as seen in our study. Mandibular inter-canine width is however unaffected due to a lowered tongue posture seen in these children.