Longitudinal relationship between incisal tooth wear and periodontal condition.

The purpose of the study was to examine the relationship between the longitudinal development of incisal tooth wear and periodontal conditions in 51 persons. Stone casts obtained at the ages of 15 and 27 yr were used to assess incisal wear according to a graded scale, the Incisal wear Index (IwI). The wear increase after 12 yr, delta IwI, was related to the various health index scores at the age of 15 yr, including the Plaque Index (PlI) and Gingival Index (GI) systems. The chi-square tests showed a statistically significant association between delta IwI and periodontal condition in 15-yr-olds. Thus, relatively low PlI and GI values were accompanied by relatively high delta IwI values. It was concluded that in 15-yr-olds, PlI and GI levels are clinical predictors of future wear (delta IwI) of maxillary and mandibular central incisors. Pocket depth (PD) was a less valuable clinical predictor of such wear.

Longitudinal relationship between incisal occlusion and incisal tooth wear.

The purpose of the study was to evaluate the longitudinal relationship between incisal wear of central incisors and the size of vertical overbite (OB) and horizontal overjet (OJ). Stone casts of 51 subjects were used for the determinations. Casts were obtained when the subjects were 15 and 27 years old. Statistical analysis was performed with the t test for paired samples, the chi-square test of association. Pearson's product moment correlation coefficient, and Spearman's rank correlation coefficient. Both overbite and overjet diminished after 12 years, and incisal wear increased. It was concluded that increase in age, incisal wear, vertical overbite and incisal occlusion (OB/OJ) are clinical predictors of wear of maxillary and mandibular central incisors in adolescents.

Partial mouth recording of plaque, gingivitis and probing depth in adolescents.

Selection of teeth representative of the whole dentition has been used in clinical and epidemiological investigations. The present study was carried out to assess the relationship between 3 different subsets of teeth and the whole dentition for the plaque index, gingival index and probing depth. The selections were: the subset described by Ramfjord (16, 21, 24, 36, 41, 44), the CPITN Alternative I subset (17, 16, 11, 26, 27, 37, 36, 31, 46, 47) and the CPITN Alternative II subset (16, 11, 26, 36, 31, 46). The comparisons were performed on data obtained for 15-year-old adolescents. A strong correlation was observed between the whole dentition and each of the subsets for all assessments. The distribution of scores of the Ramfjord selection and the whole dentition was not statistically different. Corresponding comparisons showed that the distribution of scores of the CPITN selections and the whole dentition was statistically different. Plaque and gingival index scores of these selections underestimated 0 scores and overestimated 2 + 3 scores. Probing depths less than or equal to 2 mm were underestimated and probing depths greater than or equal to 4 mm overestimated. The bias associated with the CPITN Alt I was more pronounced than that of the CPITN Alt II subset of teeth in the adolescents examined.

Effects of the degree of overbite and overjet on dental health.

The purpose of the study was to examine whether any combination of vertical overbite (OB) and horizontal overjet (OJ) may be more favourable than others to dental health in anterior segments. The study group consisted of 74 females and 70 males. The participants were 15-years-old and had 6 anterior teeth in both jaws. The following parameters were assessed: plaque index, gingival index, probing depth, space index, filled surfaces, the number of non-aligned proximal tooth surfaces (NONAS) and the OB/OJ ratio. The results demonstrated that participants with a relatively high OB/OJ ratio (OB/OJ greater than or equal to 1.21) had a more favourable periodontal condition than participants with lower ratios. This was so in both sexes and both jaws. The OB/OJ ratio had little relation to the prevalence of filled surfaces.

Relationship between alignment conditions of teeth in anterior segments and dental health.

The purpose of the study was to examine the association between alignment conditions of anterior teeth and dental health in 15-year-old adolescents. The study group consisted of 74 females and 70 males with 6 anterior teeth in both jaws. The following parameters were assessed: plaque index (P1I), gingival index (GI), probing depth (PD), space index (SpI), filled surfaces (FS), and the NONAS-i.e., the number of non-aligned proximal tooth surfaces in each jaw counted on model casts. Statistical examination of the data was performed using chi 2 tests of association and homogeneity and correlation coefficient analyses. In both sexes and both jaws, anterior tooth segments with none or few non-aligned teeth had a more favourable periodontal state than segments with an increased number of non-aligned teeth. Likewise, tooth segments with none or few non-aligned teeth had a reduced frequency of proximal fillings compared to segments with an increased number of non-aligned teeth. In males, the distribution of restorations in the anterior segment of the lower jaw was relatively homogeneous in the 3 groups.

Effects on dental health of spacing of teeth in anterior segments.

The purpose of the study was to examine the relationship between spacing and dental health in 15-year-old adolescents. The whole sample consisted of 156 subjects. Out of them, 74 females and 73 males with 6 anterior teeth made up the study group for examination of the upper jaw. 75 females and 75 males had 6 anterior teeth in the lower jaw and made up the study group for examination of the lower jaw. The Plaque Index (PlI) and the Gingival Index (GI) were recorded. Probing depths (PD) were measured as explained by Glavind & Løe. Filled surfaces (FS) were taken from the individual case sheets and controlled clinically. The spacing of the individuals was assessed by counting the number of proximal surfaces without visible contact with the adjacent proximal surfaces, on model casts. The sum of proximal surfaces without contact made up the Space Index (SpI) of the individual jaw. Parametric and non-parametric statistical methods were used to analyze the data. In both sexes and both jaws proximal surfaces without interdental contact had a more favourable periodontal condition than surfaces with contact. In the upper jaw of both sexes, proximal surfaces without interdental contact had a reduced number of filled surfaces compared to surfaces with contact. The linear relationship between SpI and FS was significant, i.e., an increased number of surfaces without contact was accompanied by a reduced number of filled surfaces. In the lower jaw, the differences between the SpI groups and the linear relationship between SpI and FS did not reach significance. In both sexes and both jaws, proximal surfaces without fillings had a more favourable periodontal state compared to surfaces with fillings. Indications are that the summation effect of the presence of interdental contact and the presence of fillings contributed to the differences in periodontal condition between surfaces with and without interdental contact.