Periodontal disease prevalence in different age groups in Japan as assessed according to the CPITN

A CPITN survey was conducted involving 12,832 Japanese subjects from 7 to 64 years of age. Subjects under 18 were schoolchildren, and 18-year-old and older subjects represented various social backgrounds, having been randomly selected from both urban and rural Japan. Fifty percent of the 7-yr-old children had signs of periodontal disease, and this percentage increased with increasing age. In those under 14, this increase in periodontal disease was mainly due to an increase in the proportion of children developing dental calculus. Subjects with 6 mm or deeper pockets were observed starting from the 20-29-yr-old age group. In subjects over this age, the prevalence of periodontal disease was higher in men than in women. The percentages of subjects having pathologic pockets had increased remarkably in the 30-44-yr-olds. In the 45-64-yr-old group, almost all subjects had some sign of periodontal disease, and the percentage of those with 4 or 5 mm pockets and 6 mm or deeper pockets were 37% and 21%, respectively.     

Assessment of periodontal disease in an adult population survey in Taipei city using CPITN and GPM/T indices

The community periodontal index of treatment needs (CPITN) has been recommended for epidemiological surveys of periodontal status and treatment needs. The prevalence of gingivitis, periodontitis and missing teeth in a study population has been determined using the CPITN and GPM/T (gingivitis: periodontitis: missing teeth) indices. In this study, a survey of periodontal disease was performed among the adult population of Taipei City using the CPITN index. A total of 673 dentated persons (male 339, 50.4%; female 334, 49.6%) were examined and surveyed. Data were then divided into five age groups, 15-19, 20-29, 30-44, 45-64 and 64+. The prevalence of periodontal disease was analyzed using the percentage or sextant from all teeth. Treatment needs were determined by the worst periodontal score per sextant. It was found that about 91% of subjects suffered from various degrees of periodontal disease in at least one tooth. Gingivitis and periodontitis were 86.9% and 33%, respectively. Among them 48.9% had missing teeth. The prevalence of periodontitis and missing teeth increased with age. Most of them involved oral hygiene instruction and scaling. About 11.0% of the subjects needed periodontal surgery. Higher proportions of attachment loss with gingival recession caused by destructive periodontal disease were found in older persons who did not require periodontal surgery. It was concluded that endemic gingivitis and calculus, a moderate prevalence of shallow pockets and a low prevalence of deep pockets were observed among adults in this group in Taipei City and that the CPITN is a practical epidemiological and public health method for screening the periodontal status and treatment needs of a population.     

The change of periodontal treatment needs in a population of Ljubljana,Slovenia, over a ten year period

A follow-up study was performed to assess the change of periodontal treatment needs in the adult population of Ljubljana, Slovenia, over a ten year period. In the initial survey, conducted from 1983-1987, 1,609 dentate subjects in the range from 15-65 years of age were clinically examined. Ten years later of the 1,609 invited subjects a total 555 (34.5%) came to the oral re-examination. During the intervening period 3.1% of them had become edentulous. Periodontal treatment needs in both surveys were assessed by the Community Periodontal Index of Treatment Needs methodology. At the initial examination 2.4% of 1,609 subjects were found to be without any signs of periodontal disease, 97.6% needed oral hygiene instruction, 77.71% needed scaling and 20.3% of them needed complex periodontal treatment. Ten years later, of the 538 dentate subjects aged 25-75 years, only 0.7% of presented with healthy periodontal tissues, 99.3% needed oral hygiene instruction, 93.9% needed scaling and 27.3% needed periodontal surgery. In both surveys advanced periodontal disease in the Ljubljana population was limited to 6.0% and 8.3% of all sextants respectively. After evaluation of the population of the same age in both surveys (25-65-year-old groups) a slight decrease in subjects with healthy periodontal tissues (1.21% vs. 0.84%) was observed. In comparison, there was an increase of subjects with shallow pockets (24.8% vs. 31.1%) and a slight decrease of subjects with deep periodontal pockets (27.7% vs. 24.1%). Comparing the results we concluded that the prevalence and severity of periodontal disease in the Ljubljana population remained similar in both surveys. The findings of the present follow-up study suggest a need for more efficient primary and secondary preventive measures in order to decrease the prevalence and severity of periodontal disease in Ljubljana and Slovenia.     

Relative influence of calculus and overhangs of fillings on the frequency of score 2 of the CPITN

Periodontal treatment needs of 895 dentate subjects aged 25, 35, 50 and 65 yr were studied according to the Community Periodontal Index of Treatment Needs (CPITN). The relative influence of calculus and overhanging margins of restorations on the need for professional debridement of shallow (less than or equal to 3 mm) pockets was calculated. The mean number of sextants per person scoring CPITN Code 2 decreased from 2.6 in the 25-yr group to 1.1 in the 65-yr group. Overhangs of fillings alone were detected in 0.8 sextants of the 25-yr-olds and in 0.1 sextants of the 65-yr-olds. The mean number of sextants containing calculus with or without overhangs decreased from 1.8 in the 25-yr group to 1.0 in the 65-yr group. The relative influence of calculus was higher in the aged than in the young population. The recording of overhangs is important for accurate assessment of periodontal treatment needs in populations with a high caries experience.     

A national survey of periodontal treatment needs of adults in the Philippines

2,400 dentate adults (15 to 65 yr), representative of rural and urban areas of all twelve regions of the Philippines, were screened for their periodontal treatment needs using the Community Periodontal Index of Treatment Needs (CPITN). The distribution pattern of CPITN scores for the criteria, healthy, gingival bleeding (on probing), calculus, 4-5 mm and 6 mm or deeper periodontal pockets was similar for adult populations in each of the twelve regions. Calculus predominated as the most frequently recorded score, with a prevalence exceeding 70% in young adults but decreasing to about 40% in older adults. The decrease in prevalence of calculus with age was associated with an increase in 4-5 mm pocketing, 4% in young adults and about 60% in older adults. Periodontally healthy mouths and cases of deep pocketing were relatively uncommon. The assessed treatment need was predominantly Type 2 (scaling and improved oral hygiene). Need for complex treatment (Treatment Need Type 3) was low involving only 4% of older adults. The pattern of assessed periodontal treatment needs of adults in the Philippines was indicative of endemic gingivitis and calculus and moderate to low prevalence of pocketing.     

Periodontal diseases in a university setting in Ivory Coast]

The aim of this study was to measure the prevalence and severity of periodontal diseases, and also to evaluate periodontal treatment needs of the students of Abidjan University, in Ivory Coast. 647 students were randomly selected and interviewed to determine age, sex and oral hygiene habits; the subjects were examined for tooth mobility, plaque, calculus, gingival bleeding, periodontal probing depths and gingival recessions. The oral hygiene was insufficient: 86.08% of the subjects presented calculus--The average of sextants presenting gingival bleeding was to 4.03 and to 3.43 for calculus. The prevalence and severity of periodontal pockets were low: only 0.36 sextants on average presented pockets of 4-5 mm and 0.025 sextants presented pockets of 6 mm or more. As concerns periodontal treatment needs, 89.64% of subjects needed oral hygiene advises, 84.85% needed scaling/root planning, and 1.39% needed complex periodontal treatment. Our findings confirm the fact that destructive periodontal disease is not an inevitable consequence of gingivitis. The information, screen, and prevention should begin reality in our daily practice.     

Periodontal health among recent immigrants from Quara,rural Ethiopia and indications for periodontal health care

OBJECTIVES: To investigate periodontal status and oral hygiene practices among recent new immigrants from Quara, Ethiopia, with the aim to maintain and promote their periodontal health. METHODS: Periodontal status was recorded for a total of 487 participants using the Community Periodontal Index (CPI). Age was grouped into 13-17, 18-24, 25-34, 35-44, and 45-65 years, and its association with 'worst CPI' was tested. Information on oral hygiene behaviour was collected by interview. RESULTS: The percentage of subjects with calculus is most common in all age groups. Low levels of periodontal pockets in the presence of calculus and very low levels of deep pockets were detected. Differences in CPI scores among the various age groups were statistically significant (p<0.0001). Oral hygiene practice is rare among children in Ethiopia, but a considerable proportion (53%) immediately adopted the local common custom and started brushing their teeth in Israel. Among the adults, oral hygiene practice with chewing sticks was common. CONCLUSIONS: Periodontal health promotion of this population should be targeted towards the entire population by enhancement of self-care oral hygiene measures. Periodontal treatment of this population, especially scaling and root planing remains controversial. The presence of inferior oral hygiene and high levels of calculus, together with low levels of periodontal pathology, raises important thoughts regarding the natural history of periodontal disease development.     

Periodontal conditions in 35-44 and 65-74-year-old adults in Denmark

OBJECTIVES: To assess the periodontal health status in the Danish adult population and to analyze how the level of periodontal health is associated with age, gender, urbanization, socio-economic factors, and dental visiting habits; furthermore, to compare the periodontal health status of Danish adults with that of adults in other industrialized countries. MATERIAL AND METHODS: A cross-sectional study of a random sample of 1,115 Danish adults aged 35-44 years and 65-74 years. Data were collected by means of personal interviews and by clinical examinations in accordance with the World Health Organization Basic Methods Criteria. RESULTS: The clinical examination revealed a low prevalence of healthy periodontal conditions in both age groups: at age 35-44 years 7.7% and at age 65-74 years 2.4% had healthy periodontal conditions. A high proportion of the elderly had scores of severe periodontal health; more than 82% of older participants had pockets of 4-5 mm or deeper against 42% in younger adults. In both age groups, the mean number of teeth with periodontal pockets deeper than 4-5 mm was high in individuals with low education. Only a weak association between periodontal health and income was found. High Community Periodontal Index scores were seen for irregular dental visitors, but in the 35-44-year-olds deep periodontal pockets were more often seen among young regular dental visitors. The multivariate analysis showed that participants with low or medium levels of education had significantly more teeth with shallow and deep pockets than those with high education. Persons with regular dental visiting habits had fewer teeth with gingival bleeding, shallow and deep pockets than individuals with irregular dental visiting habits. CONCLUSION: Reorientation of the Danish dental health-care services is needed with further emphasis on preventive care, and public health programs should focus on risk factors shared by chronic diseases in order to improve the periodontal health of Danish adults.     

Periodontal status and treatment needs among Spanish hospitalized psychiatric patients

The purpose of this study was to evaluate the periodontal status and treatment needs (by CPITN) of 565 patients hospitalized in a psychiatric facility in Seville, Spain. The results of this study showed that 31.7% of the patients were edentulous and that 68.3%% were dentate. Of the dentate subjects, 8.5% were found to have a healthy periodontium, 14.2% had bleeding on probing, 43.8% had calculus, 24.6% had shallow pockets, and 8.9% had deep pockets. The results of the study also showed that the severity of periodontal disease increased significantly with age and the length of time of hospitalization. The need for oral hygiene instruction among the dentate population was determined to be 91.5%, and the need for treatment (oral prophylaxis and scaling) was 77.3%. These findings suggest that hospitalized psychiatric patients in Spain are in dire need of preventive dentistry .     

Periodontal treatment needs, by CPITN, among employees of a Jerusalem hospital.

A survey, employing the Community Periodontal Index of Treatment Needs (CPITN), was conducted among 344 employees of a Jerusalem hospital. Of the population surveyed, 2.2 per cent demonstrated totally healthy mouths, 1.5 per cent had, at the worst, bleeding symptoms, 13.3 per cent had calculus, 53.4 per cent had 4-5 mm ('shallow' according to WHO) pockets and 29.6 per cent had deep pockets (6 mm or more) as their worst CPITN scores. Results revealed an average of 0.55 edentulous sextants, 0.68 healthy sextants, 0.87 sextants with bleeding symptoms, 1.36 with calculus, 1.95 with 4-5 mm pockets and 0.61 sextants with deep pockets. In general, females were healthier than males, had a significantly greater number of healthy sextants, less sextants with calculus and less sextants with deep pockets. A deterioration in periodontal health with age was evident, according to mean number of sextants per person by CPITN scores. Associations were also analysed between CPITN and demographic variables. Few significant associations were revealed. Based on FDI and WHO estimates, the calculated periodontal treatment needs for the hospital employees was found to be about 2 hours per person. Compared with data for other countries, as reported by the WHO, this status demands serious efforts to be made towards periodontal health promotion.     

Periodontal treatment needs in 12 and 15 to 19-year-old school children in the Caribbean island of Antigua, 1990

A national survey was undertaken in 1990 to investigate the periodontal treatment needs in 12 and 15 to 19-year-olds residing in urban and rural areas of Antigua. Using the CPITN procedure, examination of 246 12 year-old children and 456 adolescents (15–19 years) revealed that the CPITN scores of healthy, gingival bleeding, calculus, 4 or 5 mm and ≥6 mm periodontal pockets were distributed similarly in urban and rural areas. Calculus was the most commonly recorded score, with a prevalence of 46% in 12-year-olds and 56% in 15–19 year-olds. 4 or 5 mm pockets were found in 14% of adolescents, affecting on average less than one sextant per subject, but deep pockets were uncommon, 26% of 12-year-olds and 14% of adolescents had periodontally healthy mouths. Scaling and oral hygiene instruction were the predominant treatment needs in both age groups, but the requirement for complex periodontal care in adolescents was low – 3% only.     

Periodontal treatment needs in a Spanish school population

The aim of this study was to assess the periodontal treatment needs of the population under 20 years of age in Spain. 1469 young people, aged 7, 12 and 15-19 years, and representing the urban (60%) and rural (40%) population from Spain were evaluated using the Community Periodontal Index of Treatment Needs (C.P.I.T.N.). In the first age group (7 years), 12% presented calculus or overhanging restorations, and 45% had bleeding upon probing only. In the age group of 12 years the proportion of individuals with calculus, overthanging restorations or moderate pocket depths was 39%, while 38% had gingivitis as their highest treatment need. In the oldest group (15-19 years) the number of subjects with bleeding upon probing decreased to 17%, while the percentage of individuals having moderate pockets, calculus or overhanging restorations increased to 67%. 1% of this youngsters had pockets of 6 mm. or over. At age 7, only 30% had "acceptable gingival health", and no more than 15% of the 18 year-olds reached this condition.     

青海省人群牙周健康状况流行病学调查报告

目的了解青海省人群牙周健康的状况,为牙周疾病的防治提供基线资料。方法根据第三次全国口腔健康流行病学调查牙周状况的检查标准,采用多阶段、分层、等容量、随机抽样的方法,对青海省12、35～44和65～74岁3个年龄组的牙龈出血、牙结石、牙周袋及附着丧失等进行流行病学抽样调查。结果1）青海省12、35～44、65～74岁年龄组牙龈出血检出率分别为98.74%、97.84%和92.23%,牙结石检出率分别为89.76%、99.87%和92.87%。2）35～44岁年龄组浅牙周袋检出率为34.64%,深牙周袋检出率为5.58%;65～74岁年龄组浅牙周袋检出率为50.45%,深牙周袋检出率为13.12%。3）35～44岁年龄组附着丧失4～5、6～8、9～11、12 mm或以上的检出率分别为40.74%、18.78%、4.82%、1.78%;65～74岁年龄组附着丧失4～5、6～8、9～11、12 mm或以上的检出率分别为71.21%、51.34%、20.51%、7.01%。结论青海省人群口腔卫生状况很差,中老年人牙周袋及附着丧失的程度比较严重,必须加强对牙周疾病的预防。     

Assessment of periodontal knowledge and periodontal status of an adult population in Jordan

The aim of this study was to assess periodontal knowledge and periodontal status in 20-60-year-old adult population in northern Jordan. A convenient sample consisting of 722 adults was included in this study. A questionnaire incorporating items related to socio-demographic and periodontal knowledge questions was completed before clinical examination, using the Community Periodontal Index of Treatment Needs (CPITN). The results showed that the proportions of subjects who reported bleeding gums, gums' irritation, rough tooth surface and gum disease decreased steadily with age, there is an evident linear trend with high statistical significant difference among various age groups (P < 0.001). Furthermore, the proportions of subjects who answered correctly the periodontal knowledge questions related to plaque definition and its role in disease aetiology and prevention, decreased with age, with a high significant difference for all knowledge questions (P < 0.001). The prevalence of subjects with healthy periodontium (score 0) decreased with age, being 41.1% among 20-29-year-old group and 11.1% in 50-60-year-old group. Similar trend was seen for bleeding on probing (score 1) whilst calculus deposit (score 2) was the major problem in all age groups over 29 years. The prevalence of periodontal pockets was relatively low, with a range of 4.5-18.6% for shallow pockets (score 3) and 2.9-11.1% for deep pockets in younger and older age groups, respectively. Younger age group had more healthy sextants than older age groups. In addition, sextants with bleeding on probing were highest in 20-29-year-old age group (1.8) compared with that in 50-60-year-old age group (0.60) whilst those with calculus deposits varied slightly among different age groups (1.50-1.65). Sextants affected by shallow or deep pockets increased steadily with age. Such a finding was also noted in excluded sextants, with an increase from 0.15 at 20-29 year-old group to 0.94 at the age of 50-60 years. It is concluded that health knowledge and status related to periodontal disease is still poor in northern Jordan. Therefore, dental health education provision is necessary to improve oral health knowledge and conditions among population in general and among older population in particular.     

Community periodontal index of treatment needs and prevalence of periodontal conditions

BACKGROUND/AIMS: In 1977, the World Health Organization (WHO) proposed a new index, the community periodontal index of treatment needs (CPITN) to evaluate the periodontal treatment needs of populations. The aim of this study is to compare different approaches of recording and presenting the CPITN. METHODS: A sample of 2110 subjects aged 35-44 years were examined between September 1994 and July 1995, throughout the province of Quebec, Canada. For each tooth (3rd molars excluded), the presence of bleeding and calculus, the level of epithelial attachment, and the depth of periodontal pockets were measured. Periodontal pocket depths were measured from the edge of the free gingiva, at 2 sites (mesiovestibular and vestibular), as well as all around the tooth. RESULTS: Only 8.5% of adults had at least one tooth with a 6 mm or deeper periodontal pocket when probing on 2 sites, whereas if probing is done all around the tooth, this percentage is 2.5x higher (21.4%). The partial recording of pocket depths (10 index teeth recommended by WHO, or 2 quadrants chosen at random) resulted in an underestimation of the prevalence of subjects with at least one tooth with a periodontal pocket (CPITN score 3 and 4). Among subjects with at least one tooth with a 6 mm or deeper periodontal pocket, 12% were not detected with the 10 index teeth recording, and 25% go undetected with the measure on 2 quadrants. Finally, using the % of subjects with periodontal pockets overestimates the prevalence of deep pockets compared with using sextants. Indeed, close to 30.0% of sextants have no treatment needs, whereas only 5.2% of subjects are in this category. Similarly, 7.7% of sextants have at least one tooth with a 6 mm or deeper periodontal pocket, yet there are 3x more subjects in this category (21.4%).     

Dental health behaviors and periodontal disease indicators in Danish youths

The purpose of the present study was to analyse the epidemiologic relationship between dental health behaviors and periodontal disease. Indicators of periodontal disease in terms of bleeding and calculus were measured dichotomously (absence/presence). Periodontal pockets were as follows: normal pockets (0-3 mm), shallow pockets (4-5 mm), and deep pockets (6+ mm). The indicators were measured on 4 surfaces on 6 index teeth (16, 11, 26, 36, 31, 46) in 1984-85. The highest value for each tooth of bleeding (0/1), calculus (0/1) and pockets (0/1/2) was used for calculation of the bleeding index, the calculus index and the pocket index. The participation rate in 1984-85 was 86%, and the study population involved 368 males and 388 females. Information concerning dental health behavior was obtained both in childhood (1974) when the individuals were 9-10 years of age, and in adulthood (1984-85) when the individuals were 20-21 years of age. Information concerning dental health behaviors in adulthood, i.e., regularity of dental visits, frequency of tooth brushing, and regular use of interdental aids, was obtained through a self-administered questionnaire (1984-85). Dental health behaviors in childhood (1974) was operationalized as level of plaque, gingivitis, and dmfs. The results showed that dental health behaviors in childhood and in adulthood were together responsible for 9.4-13.8% of the variance in level of periodontal disease indicators. Determinants of early dental health behaviors in terms of plaque and dmfs at age 9-10 years were significant predictors in pocket index at age 20-21.(ABSTRACT TRUNCATED AT 250 WORDS)     

Periodontal treatment needs in Argentine adult subjects

The aim of the present study was to assess the periodontal treatment needs of the population that spontaneously sought treatment from general dentists. 3694 patients (2000 females and 1494 males, age range between 18 and 84 years) were evaluated using the Community Periodontal Index (CPI). Data were reported according to the percentage of subjects with the highest Score: 14.3% presented pocket depth > or = 5.5 mm (Score 4), 26.4% pocket depth between 3.5 and 5.5 (Score 3), 38.3% presented pockets < or = 3.5 mm with calculus or overhanging restorations (Score 2), 17.2% pockets < or = 3.5 mm with bleeding upon probing without calculus (Score 1) and 3.2% were healthy (Score 0). Analyzing the data according to age it was observed that in the group > 40 years the percentage of patients with Score 4 was higher (25.1%) compared to the other two groups of 18-34 years (6.4%) and 34-45 years (14.3%). Only 16.4% of the patients consulted for periodontal reasons (gingival bleeding or tooth mobility), whereas 88% requested treatment for other reasons (pain, caries, esthetics, replacement of teeth, etc.). However 77% of the patients in this last group needed periodontal treatment. 96.8% of the patients attending the general dentistry office needed periodontal treatment: 17.2% oral hygiene instruction, 65.2% oral hygiene instruction and scaling and 14.3% complex treatment.     

Needs and implementation of preventive dentistry in China

Based on a literature review and recent surveys, the needs and implementation of preventive dentistry in China have been estimated. The average DMFT of 12- and 15-yr-old schoolchildren in Beijing were 1.61 and 2.11 respectively. The caries prevalence was higher in the coastal cities in the south. The caries rate was also higher in urban areas than in rural areas. There were some controversies in the results of fluoridation studies with one study reporting as high as 47.2% of the children to be afflicted with enamel fluorosis. The community periodontal disease status and treatment needs index (CPTNI) showed that 93% of the 12-yr-olds had bleeding, 98% had calculus and 15% had shallow pockets, with 100% of the children needing prophylaxis. There was a high prevalence of dental malocclusion with 54% of schoolchildren with dental anomalies, of whom 36% needed treatment. Much emphasis had been placed on oral pathology, oral medicine and maxillofacial surgery in the curriculum of Stomatology in Chinese dental schools.     

Predictive values of self-reported periodontal need: National Health and Nutrition Examination Survey III

BACKGROUND: This study assessed predictive values of self-reported periodontal need to identify periodontal conditions using clinical examinations as the gold standard. METHODS: We identified 12,370 adults > or = 18 years of age in the third National Health and Nutrition Examination Survey. Self-reported periodontal need was based on participants responding that gum treatment and/or cleaning was needed when asked: "What type of dental care do you need now?" Two periodontal conditions were at least two sites with pockets (pockets > or = 3 mm or pockets > or = 4 mm) and at least two sites with calculus. Main outcomes were: 1) positive predictive value (PPV(Clean)): proportion of those who self-reported the need for cleaning who had calculus; and PPV(Gum): proportion who self-reported the need for gum treatment who had pockets; 2) negative predictive value (NPV(Clean)): proportion of those who self-reported no need for cleaning who did not have calculus; and NPV(Gum): proportion who self-reported no need for gum treatment who did not have pockets; 3) association between predictive values and sociodemographic and behavioral characteristics; and 4) proportion of individuals with specific sociodemographic and behavioral characteristics whose self-reported periodontal need predicted periodontal conditions. RESULTS: The prevalence of periodontal conditions influenced predictive values. Calculus prevalence = 85%: corresponding PPV(Clean) = 88% and NPV(Clean) = 16%. Prevalence of pockets > or = 3 mm = 47%: corresponding PPV(Gum) = 62% and NPV(Gum) = 54%. Prevalence of pockets > or = 4 mm = 11%: corresponding PPV(Gum) = 25% and NPV(Gum) = 90%. Ninety percent of 30- to 44-year-old minority female smokers who did not visit the dentist in the past year and reported the need for gum treatment had pockets > or = 3 mm (PPV(Gum) = 90%). CONCLUSIONS: Self-reported periodontal need (cleaning/gum treatment) predicted the presence of the prevalent conditions (calculus/pockets > or = 3 mm). Not reporting a need for periodontal treatment predicted the absence of the less common condition (pockets > or = 4 mm) but not the more prevalent condition (calculus).     

The effects of ultrasonic scaling with oral hygiene education on the distribution of pathological pockets using CPITN diagnostic standards

Thirty-three subjects aged 20-44 years, selected from Japanese company employees who had been given CPITN Codes of 3 or 4, received a treatment of ultrasonic scaling to investigate any changes in the distribution of pathological pockets after this treatment using CPITN diagnostic standards. A pathological pocket was defined as a pocket with a depth of 4 mm or deeper as described in the CPITN system. The results demonstrate that the number of teeth with pathological pockets was significantly reduced from 6.2 to 3.4 (45 per cent reduction) after scaling with an ultrasonic instrument requiring at most 30 minutes per subject. The reduction in pathological pockets was attributed to an improvement in shallow pockets rather than deep pockets. These results imply that as far as shallow pockets are concerned, one episode of scaling with ultrasonics is effective in reducing the extent of periodontal disease. Comparison between the number of sextants with shallow pockets before and after scaling further revealed that more improvements were observed in the subjects aged 20-29 years than in those aged 30-44 years. These results suggest that subjects aged 20-29 years with shallow pockets should be given first priority for scaling programmes in an adult population. The results also indicate that the CPITN diagnostic standards, in which the probe measures what is 'normal' and 'abnormal', is appropriate for the evaluation of periodontal status in an epidemiological study.