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The majority o f subjects (97%) were dentate. Only 33 participants were edentate.

Therefore most o f the analyses in this report are based on the 1196 dentate people.

Among people with natural teeth, 596 o f the 1196 had 26-28 natural teeth (excluding third molars). 77.9% had 21 or more natural teeth and 22.1% o f subjects had 20 or fewer natural teeth (Table 5.8). 69.2% had at least 11 OPs, 74.2% had at least 5 POPs and 82.9% had at least 4 AOPs (Table 5.8).

73.1% o f dentate subjects had 26-28 replaced plus natural teeth, 18.6% had 21-25 replaced plus natural teeth and 8.3% had 20 or less replaced plus natural teeth. 81.7%

Chapter 5 R esults

had at least 11 OPRs and 84.4% had at least 5 POPRs. 90.4% of people had at least 4 AOPRs. About one in six people had 0 to 10 OPRs and 0 to 4 POPRs. Just one in ten people had 3 or less AOPRs (Table 5.8).

In dentate people, 42.7% had no unfilled spaces and 45.5% had no unfilled posterior spaces. 83.4% peoplp had no unfilled anterior spaces. About a quarter o f people had at least 3 or more unfilled spaces or unfilled posterior spaces but only 6.1% had 3 or more unfilled anterior spaces (Table 5.8).

The frequency distributions o f the main clinical variables were skewed. Therefore, the minimum, maximum and a number o f percentiles - 5%, 25%, 50% (median), 75%, and 95% - were used instead o f the means (Table 5.9).

The number o f natural teeth ranged from 1 to 28 teeth, with a median o f 25 teeth while number o f natural plus replaced teeth ranged from 1 to 28 teeth with median o f 27 teeth.

The median DMFT was 4. Few people had decayed and filled teeth, less than 5% o f the sample had more than 2 decayed teeth, or more than 4 filled teeth. The number of missing teeth ranged from 0 to 27 teeth with a median o f 3 teeth. The number o f teeth that had increased mobility (grade 1 or more) ranged from 0 to 20, but less than 5% the subjects had more than 5 mobile teeth (Table 5.9). In this thesis, DMFT did not include root caries.

The medians for OPs, POPs and AOPs were 14, 9, and 6 pairs of teeth respectively.

When considering replaced missing teeth, people had a higher number o f occluding pairs for natural plus replaced teeth. The medians o f OPRs, POPRs and AOPRs were 16,

10, and 6 pairs respectively (Table 5.9).

Unfilled spaces between teeth were due to missing teeth not being replaced by a fixed or

removable prosthesis. The number o f unfilled spaces ranged from 0 to 27 with a median o f 1. Less than 5% o f subjects had more than 11 unfilled spaces. The median o f unfilled posterior spaces was 1. The majority o f subjects had no unfilled anterior spaces, less than 5% had more than 3 unfilled anterior spaces (Table 5.9).

A total o f 526 (44.0%) dentate people had a prosthesis. 49 subjects (4.1%) wore partial dentures in both jaws, 43 subjects (3.5%) wore only a partial denture(s) in the upper jaw and 29 subjects (2.3%) wore only a partial denture (s) in the lower jaw. 125 (10.5%) subjects had bridge(s) in both jaws. 126 subjects (10.5%) had a bridge only in the upper jaw and 73 subjects (6.1%) had a bridge in the lower jaw (Table 5.10).

O f the 33 edentulous subjects, 30 (91%) wore complete dentures in both jaws, 1 (3%) wore a complete denture in the upper jaw only, while only 2 (6%) subjects did not wear any denture at all (results not presented).

5.3.2.2. The relationships between clinical dental status and sociodemographic factors

This section presents the results on the relationships between clinical dental status and sociodemographic factors.

There were significant differences in DT (p = 0.004), MT (p < 0.001) and DMFT (p <

0.001) but not FT (p = 0.4) by age group. Older people were more likely to have decayed and missing teeth. There were significant differences in MT (p = 0.02) and FT (p < 0.001) but not DT (p = 0.17) and DMFT (p = 0.60) by sex. There were significant differences in DT (p = 0.002) and FT (p < 0.001) but not MT (p = 0.80) and DMFT (p = 0.36) by occupation. There were significant differences in DT (p = 0.02), FT (p < 0.001) but not MT (p = 0.87) and DMFT (p = 0.69) by self-assessed social class. People from

Chapter 5 R esults

manual occupation or lower self-assessed social class were more likely to have caries when compared to those from non-manual occupation or higher self-assessed social class. The proportion and number o f missing teeth were strongly associated with age.

About 80% o f people had missing teeth. Slightly more males and people from manual occupations had missing teeth compared to females and people with non-manual occupations. People reporting lower social class had more missing teeth compared to people reporting high social class. Females, people with non-manual occupations and with higher self-assessed social class had higher mean filled teeth than male, those with manual occupation and lower self-assessed social class, but these differences were not significant (Table 5.11).

There were significant differences in both number o f natural teeth and number o f natural plus replaced teeth by age group (p < 0.001). The number o f teeth decreased as age increased (Table 5.12). There were also significant differences in the numbers o f natural plus replaced teeth, but not in the numbers o f natural teeth, by sex (p = 0.02), occupation (p = 0.02), and education (p < 0.001). Females, people with non-manual occupations and people with high education had slightly more natural plus replaced teeth compared with males, people in manual occupations and people with low education respectively (Table 5.12). This indicates that women, people from non-manual occupations and higher self-assessed social class were more likely to replace their missing teeth. There was no significant difference in both numbers of natural teeth and numbers o f natural and replaced teeth by personal income and self-assessed social class (Table 5.12).

There were significant differences by age in numbers o f OPs, POPs, AOPs OPRs, POPRs, and AOPRs (p < 0.001). As age increased, numbers o f OPs, POPs, AOPs, OPRs,

and AOPRs by sex (p = 0.02 for both tests) by occupation (p = 0.05 and p = 0.02).

Females and people with non-manual occupations had more OPRs and AOPRs compared to males and people with manual occupations but the clinical differences were small and the differences were less than 0.5. There were no significant differences in OPs, POPs, AOPs, and POPRs by sex and occupation, and no significant differences in OPs, POPs, AOPs, OPRs, POPRs, and AOPRs by self-assessed social class (Table 5.13-14).

There were significant differences in the numbers o f unfilled spaces, unfilled posterior spaces, and unfilled anterior spaces by age (p < 0.001). With all o f these increased as age increased (Table 5.15). Older people were more likely to have unfilled spaces (including unfilled posterior spaces, and unfilled anterior spaces). There were also significant differences in unfilled spaces (p = 0.02) and unfilled anterior spaces (p = 0.001) by sex and unfilled spaces (p = 0.03) and unfilled posterior spaces (p = 0.008) by occupation. Males had more unfilled spaces and unfilled anterior spaces compared to females. People with manual occupations had more unfilled spaces and unfilled posterior spaces when compared to people with non-manual occupations (Table 5.15).

Similar results were obtained when data were analysed separately for people with only natural teeth and people with natural plus replaced teeth, by selected sociodemographic factors (Table 8.2-4 in Appendix 8).

About 30% o f the dentate subjects had one or more bridges and 15.2% o f subjects wore removable partial denture(s) (Table 5.16). The percentage o f people with more than one bridge, removable partial dentures, both bridge(s) and partial denture(s) or full removable dentures increased as age increased. People from non-manual occupations and higher self-assessed social class were more likely to have a bridge or removable

Chapter 5 Results

partial denture(s) and less likely to have more than one bridge when compared with people from manual occupations or lower self-assessed social class. There were large clinical differences in the percentage o f people with more than one bridge or removable partial dentures by age. For example, 23.2% o f subjects aged 75 years and over, 18.5%

o f subjects aged 65-74 years and only 7.5% o f subjects aged 55-64 years had more than one bridge or removable partial denture although these differences were not significant.

The same was true for occupation and self-assessed social class. A large clinical difference in the percentage o f people with a bridge, more than one bridge or removable partial denture(s) existed, by these characteristics. However, there was no significant difference in the percentage o f people with different types o f prostheses, by age, sex, occupation and self-assessed social class (Table 5.16).