Preventive orientation and caries management by Iranian dentists

Ehkäisypainotteisuus karieksen hoidossa: iranilaishammaslääkärien hoitovalinnat Karies aiheuttaa hampaiden kovan pinnan ja hammasluun syöpymistä, joka lopulta näkyy ”reikänä”. Iästä riippumatta kariesvaara vaanii kaikkia hampaiden omistajia, vauvasta vaariin, ja lähes kaikilla aikuisilla on suussaan merkkejä karieksesta. Karies etenee yleensä hitaasti ja antaa siten aikaa ehkäisevälle hoidolle. Tämä etsikkoaika jää usein käyttämättä, ja karieksen hoito painottuu reikien paikkaamiseen. Karies voitaisiin pitää kurissa sen ehkäisyyn kehitetyillä monipuolisilla keinoilla. Hammaslääkärit ovat avainasemassa, sillä he tekevät kauaskantoisia valintoja — hoidetaanko kariesta paikkaamalla vai valitaanko ehkäisevä hoito? Valintojen taustalla ovat hammaslääkärin tietotaso, asenteet ja omat terveystavat sekä potilaiden ja vastaanoton aiheuttamiksi koetut esteet. Tämä kyselytutkimus selvitti karieksen hoitovalintoja ja niiden taustoja Iranissa. Kysymyslomakkeet jaettiin kahdessa hammaslääkärien kongressissa Teheranissa (2004─2005) ja palautettiin nimettöminä. Kysely kartoitti hammaslääkärien tietoja karieksen ehkäisykeinoista ja asenteita ehkäisyä kohtaan sekä koettuja esteitä sen toteuttamisessa. Hoitovalintoja selvitettiin tarkasti kuvattujen esimerkkipotilaiden avulla. Kysely kartoitti myös hammaslääkärien omat terveystavat: suun omahoidon, tupakoinnin ja hammaslääkärissä käynnin. Aineisto käsitti 980 iältään keskimäärin 37-vuotiasta hammaslääkäriä, joista 64 % oli miehiä. Iranilaishammaslääkärien tiedot karieksen ehkäisystä olivat fluorihammastahnan merkitystä lukuun ottamatta hyvät ja heidän asenteensa ehkäisyä kohtaan valtaosin myönteiset. Tästä huolimatta 77 % heistä olisi valinnut suuren kariesvaaran potilaalle hammaskiilteessä olevan reiän hoidoksi paikkauksen. Ehkäisyhoidoksi tarjotuista 8:sta keinosta lähes kaikki hammaslääkärit valitsivat suuren kariesvaaran potilaalle hoidoksi harjausopetuksen ja säännölliset hammastarkastukset, noin 80 % valitsi hampaiden puhdistamisen vastaanotolla ja ravintoneuvonnan, 70 % ohjeet fluorihuuhteluista kotona ja 53 % vastaanotolla tehtävän fluorikäsittelyn. Potilaiden vastustavat mielipiteet arvioitiin suurimmaksi esteeksi ehkäisevän hoidon toteuttamiselle. Hammaslääkäreistä 59 % ilmoitti harjaavansa hampaansa kahdesti päivässä; 76 % ei tupakoinut ja 56 % kertoi aina ehdottavansa tupakoivalle potilaalle tupakoinnin lopettamista. Hammaslääkärien ehkäisypainotteisuus karieshoidossa oli naisilla vahvempi kuin miehillä. Tulosten perusteella voi päätellä, että Iranissa tulisi nykyistä selvemmin suosia ehkäisevää linjaa karieksen hoitovalintoja tehtäessä ja hammaslääkäreitä koulutettaessa. Potilastyössä koettujen ehkäisyhoidon esteiden syvällisempi ymmärtäminen edesauttaisi niiden poistamisessa.

Preventive Dentistry and Dental Education in Iran

The present study investigated the preventive orientation of the dental education system in Iran as reflected in the responses of dental school educators and dental students to a questionnaire survey. Two questionnaires, one for dental school educators and one for senior dental students, were designed and piloted. Of the 15 state dental schools in Iran, 7 were selected using a multi-stage sampling approach, and all the dental school educators and senior dental students in these schools were asked to voluntarily fill in the anonymous questionnaires. Totally, 291 educators (80%) and 270 students (82%) participated in the study. In addition to background information, both questionnaires requested information on knowledge of caries prevention, attitudes towards preventive dentistry and oral health behaviour of the respondents. The students' questionnaire also covered items concerning prevention-oriented practice, study motives, and career preferences. Contrary to knowledge and attitudes of the students, those of the educators' were positively associated with some of their academic and personal background characteristics. Women were more likely to report favourable oral self-care habits than men. The other determinants of oral health behaviour were educators' familiarity with the oral public health field, and students' attitudes towards prevention. A higher score on preventive practice among the students was associated with better oral self-care habits and positive attitudes towards prevention. Characteristics of the profession and social status and security were the top-ranked that motivated students to study dentistry, and students mainly preferred to enter postgraduate courses and private practice after graduation. To increase the orientation of Iran's health care system towards prevention, and to cope with current concepts of prevention, corresponding changes should be made in the dental education system. The results of this study support the revision of the dental curriculum by placing more emphasis on prevention-related topics and by integrating prevention-related concepts into all disciplines. Additionally, practicing dentists and dental educators should be provided with opportunities to attend continuing education courses and to conduct seminars and congresses on various aspects of preventive dentistry at home as well as abroad.

Arresting occlusal enamel caries lesions with pit and fissure sealants

The aim of this study was to evaluate the feasibility of pit and fissure sealants and the effectiveness of the two sealant methods applied in every-day practice in public dental health care in Finland. Two sealant methods were evaluated according to their effectiveness in preventing dentin caries and sealant retention. Application time with these sealant methods was compared. The survival rate of sealed first and second molars was followed for nine and 13 year periods, respectively. Caries risk evaluation and observed increased caries risk were the basis for considering sealant application. A questionnaire, sent to all public dental health centers in Finland, monitored the attitudes of the dental profession towards sealant application and explored the current policies used as well as changes noted in the sealant application protocol. DMFT (Decayed, Missing or Filled Teeth) index values collected from the health centers were evaluated. The difference in caries rate between two methods investigated was highly significant. When compared to the glass ionomer sealant method (GIC), the effectiveness of the resin-based method (RB) in preventing dentin caries was 74% and the rate difference 3%. The relative risk for RB-sealed surfaces vs. GIC-sealed surfaces of having detectable dentin caries was 0.3 (95% CI 0.12, 0.57). The retention rate of sealants was higher with RB than GIC (P<0.001). Application of RB sealant material was less time-consuming than application of GIC sealant. Occlusal dentin caries lesions were found in 4% and proximal caries in less than 2% of sealed teeth. The majority of respondents reported application of sealants on a systematic basis along with caries-risk evaluation. Those health centers sealing over suspected or detected enamel caries had lower average DMFT index values (1.0) when compared to DMFT values (1.2) of health centers applying sealants by alternative criteria. It is concluded that the RB sealant method is more effective than the GIC sealant method in preventing dentin caries. Sealant maintenance may increase the costs of a sealant program. Occlusal caries management may be improved if the applied sealant policies are changed towards an interceptive approach i.e. applying the sealants over detected or suspected enamel caries lesions instead of sealing sound teeth in a preventive manner.

Early Childhood Caries and a Community Trial of its Prevention in Tehran, Iran

Varhaislapsuuden karies ja sen ehkäisy kehittyvän terveydenhuollon maassa Varhaislapsuuden karies on merkittävä kansanterveysongelma varsinkin lapsirikkaissa maissa ja väestöissä. Karieksen hoitaminen vie paljon voimavaroja ja aiheuttaa mittavia taloudellisia seuraamuksia. Karies voi ilmaantua lapselle jo vauvaikäisenä, pian ensimmäisten maitohampaiden puhjettua suuhun. Alle 3-vuotiaiden karieksesta on kuitenkin niukasti tilastotietoja. Maailman terveysjärjestökin suosittaa tietojen keräämistä vasta 3-vuotiaiden ikäryhmästä. Heistä kariesta sairastaa Suomessa 16 %, Yhdysvalloissa 25 %, Englannissa 30 %, Iranissa 46 % ja Saudi-Arabiassa 61 %. Tämä väitöstutkimus selvitti karieksen esiintymistä ja sen vaaratekijöitä 1─3-vuotiailla Teheranissa. Lisäksi tutkimus arvioi perusterveydenhuoltoon sisällytetyn karieksen ehkäisyn tuloksellisuutta. Tutkimuskohteiksi arvottiin Teheranista 18 neuvolaa. Jokaisessa oltiin 4 päivää, jolloin kaikkia rokotuksiin tulleita 1─3-vuotiaita äiteineen pyydettiin osallistumaan tutkimukseen. Kahta lukuun ottamatta kaikki äidit suostuivat, ja aineistoon tuli kaikkiaan 504 lasta äiteineen. Kaikki 1-vuotiaat, 242 lasta äiteineen, valittiin karieksen ehkäisykokeiluun. Sitä varten neuvolat jaettiin kolmeen ryhmään, joista kaksi (A ja B) oli koeryhmiä ja yksi (C) oli vertailuryhmä. Tutkimus alkoi äidin haastattelulla. Siinä selvitettiin perheen koulutus- ja tulotaso sekä lapsen ruokinnasta imetyksen kesto, yösyötöt ja päiväaikaan nautitut makeat. Vielä kysyttiin lapsen ja äidin suuhygieniatavoista ja äidin kokemuksista lapsen suun puhdistamisessa. Sitten hammaslääkäri tutki lapsen suun ja kirjasi karieksen ja hammasplakin esiintymät. Suun tutkimuksen jälkeen äiti ja lapsi siirtyivät rokotushuoneeseen. Koeryhmissä (A ja B) äidit saivat terveydenhoitajalta suunterveyttä koskevan esitteen ja kehotuksen lukea se huolellisesti. Lisäksi ryhmässä A terveydenhoitaja kertoi suun ja hampaiden terveydenhoidosta saman esitteen avulla, ja neuvolan henkilökunta muistutti suunhoidon tärkeydestä puhelimitse kahdesti seuraavan puolen vuoden kuluessa. Vertailuryhmässä äideille ei annettu suunhoidon ohjeita. Kaikissa ryhmissä äitejä muistutettiin seuraavan rokotuskerran ajankohdasta, muttei mainittu tulevaa toista hammastarkastusta. Varhaislapsuuden kariesta sairasti ikäryhmästä riippuen 3─26 % tutkituista 1─3-vuotiaista, ja 65─76 %:lla oli hammasplakkia. Äideistä 68 % harjasi hampaansa päivittäin ja 39 % puhdisti lapsensa suun päivittäin. Mitä useammin äiti harjasi omat hampaansa, sitä paremmin hän huolehti lapsen suun puhtaudesta. Rintaruokinta oli yleistä eikä lisännyt kariesvaaraa. Yöllä pullomaitoa saavilla karies oli 5 kertaa yleisempää kuin muilla. Neuvolassa saatu ohjeistus ehkäisi selvästi karieksen syntyä puolen vuoden kokeessa.

Dental health and school-based health education among 15-year-olds in Tehran, Iran

The aim of the present study was to assess dental health and its determinants among 15-year-olds in Tehran, Iran and to evaluate the impact of a school-based educational intervention on their oral cleanliness and gingival health. The total sample comprised 506 students. Data collection was performed through a clinical dental examination and a self-administered structured questionnaire. This questionnaire covered the student s background information, socio-economic status, self-perceived dental health, tooth-brushing, and smoking. The clinical dental examination covered caries experience, gingival status, dental plaque status, and orthodontic treatment needs. Participation was voluntary, and all students responded to the questionnaire. Only three students refused the clinical dental examination. The intervention was based on exposing students to dental health education through a leaflet and a videotape designed for the present study. The outcome examinations took place 12 weeks after the baseline among the three groups of the intervention trial (leaflet, videotape, and control). High participation rates at the baseline and scanty drop-outs (7%) in the intervention speak for reliability of the results. Mean value of the DMFT (D=decayed, M=missing, and F=filled teeth) index of the 15-year-olds was 2.1, which comprised DT=0.9, MT=0.2, and FT=1.0 with no gender differences. Dental plaque existed on at least one index tooth of all students, and healthy periodontium (Community Periodontal Index=0) was found in less than 10% of students. Need for caries treatment existed in 40% of students, for scaling in 24%, for oral hygiene instructions in all, and for orthodontic treatment in 26%. Students with the highest level of parents education had fewer dental caries (36% vs. 48%) and less dental plaque (77% vs. 88%). Of all students, 78% assessed their dental health as good or better. Even more of those with their DMFT=0 (73% vs. 27%) and DT=0 (68% vs. 32%) assessed their dental health as good or better. Smokers comprised 5% of the boys and 2% of the girls. Smoking was common among students of less-educated parents (6% vs. 3%). Of all students, 26% reported twice-daily tooth-brushing; girls (38% vs. 15%) and those of higher socio-economic background (33% vs. 17%) did so more frequently. The best predictors for a good level of oral cleanliness were female gender or twice-daily tooth-brushing. The present study demonstrated that a school-based educational intervention can be effective in the short term in improving the oral cleanliness and gingival health of adolescents. At least 50% reduction in numbers of teeth with dental plaque compared to baseline was achieved by 58% of the students in the leaflet group, by 37% in the videotape group, and by 10% of the controls. Corresponding figures for gingival bleeding were 72%, 64%, and 30%. For improving the oral cleanliness and gingival health of adolescents in countries such as Iran with a developing oral health system, school-based educational intervention should be established with focus on oral self-care and oral health education messages. Emphasizing the immediate gains from good oral hygiene, such as fresh breath, clean teeth, and attractive appearance should be key aspects for motivating these adolescents to learn and maintain good dental health, whilst in planning school-based dental health intervention, special attention should be given to boys and those with lower socio-economic status. Author s address: Reza Yazdani, Department of Oral Public Health, Institute of Dentistry, University of Helsinki, P.O. Box 41, FI-00014 Helsinki, Finland. E-mail: reza.yazdani@helsinki.fi

Dental Service Utilization, Dental Health Production and Equity in Dental Care: the Finnish Experience

This thesis is grounded on four articles. Article I generally examines the factors affecting dental service utilization. Article II studies the factors associated with sector-specific utilization among young adults entitled to age-based subsidized dental care. Article III explores the determinants of dental ill-health as measured by the occurrence of caries and the relationship between dental ill-health and dental care use. Article IV measures and explains income-related inequality in utilization. Data employed were from the 1996 Finnish Health Care Survey (I, II, IV) and the 1997 follow-up study included in the longitudinal study of the Northern Finland 1966 Birth Cohort (III). Utilization is considered as a multi-stage decision-making process and measured as the number of visits to the dentist. Modified count data models and concentration and horizontal equity indices were applied. Dentist s recall appeared very efficient at stimulating individuals to seek care. Dental pain, recall, and the low number of missing teeth positively affected utilization. Public subvention for dental care did not seem to statistically increase utilization. Among young adults, a perception of insufficient public service availability and recall were positively associated with the choice of a private dentist, whereas income and dentist density were positively associated with the number of visits to private dentists. Among cohort females, factors increasing caries were body mass index and intake of alcohol, sugar, and soft drinks and those reducing caries were birth weight and adolescent school achievement. Among cohort males, caries was positively related to the metropolitan residence and negatively related to healthy diet and education. Smoking increased caries, whereas regular teeth brushing, regular dental attendance and dental care use decreased caries. We found equity in young adults utilization but pro-rich inequity in the total number of visits to all dentists and in the probability of visiting a dentist for the whole sample. We observed inequity in the total number of visits to the dentist and in the probability of visiting a dentist, being pro-poor for public care but pro-rich for private care. The findings suggest that to enhance equal access to and use of dental care across population and income groups, attention should focus on supply factors and incentives to encourage people to contact dentists more often. Lowering co-payments and service fees and improving public availability would likely increase service use in both sectors. To attain favorable oral health, appropriate policies aimed at improving dental health education and reducing the detrimental effects of common risk factors on dental health should be strengthened. Providing equal access with respect to need for all people ought to take account of the segmentation of the service system, with its two parallel delivery systems and different supplier incentives to patients and dentists.

Periodontal and dental health and oral self-care among adults with diabetes mellitus.

ABSTRACT Bakhshandeh, Soheila. Periodontal and dental health and oral self-care among adults with diabetes mellitus. Department of Oral Public Health, Institute of Dentistry, Faculty of Medicine, University of Helsinki, Helsinki, Finland. 2011. 49 pp. ISBN 978-952-10-7193-5(paperback). The aim of the present study was to assess oral health and treatment needs among Iranian adults with diabetes according to socio-demographic status, oral hygiene, diabetes related factors, and to investigate the relation between these determinants and oral health. Moreover, the effect of an educational oral health promotion intervention on their oral health and periodontal treatment needs was studied. The target population comprised adults with diabetes in Tehran, Iran. 299 dentate patients with diabetes, who were regular attendants to a diabetic clinic, were selected as the study subjects. Data collection was performed through a clinical dental examination and self-administered structured questionnaire. The questionnaire covered information of the subject s social background, medical history, oral health behaviour and smoking. The clinical dental examinations covered the registration of caries experience (DMFT), community periodontal index (CPI) and plaque index (PI). The intervention provided the adults with diabetes dental health education through a booklet. Reduction in periodontal treatment needs one year after the baseline examination was used as the main outcome. A high prevalence of periodontal pockets among the study population was found; 52% of the participants had periodontal pockets with a pocket depth of 4 to 5 mm and 35% had periodontal pockets with pocket depth of 6 mm or more. The mean of the DMFT index was 12.9 (SD=6.1), being dominated by filled teeth (mean 6.5) and missing teeth (mean 5.0). Oral self-care among adults with diabetes was inadequate and poor oral hygiene was observed in more than 80% of the subjects. The educational oral health promotion decreased periodontal treatment needs more in the study groups than in the control group. The poor periodontal health, poor oral hygiene and insufficient oral self-care observed in this study call for oral health promotion among adult with diabetes. An educational intervention showed that it is possible to promote oral health behaviour and to reduce periodontal treatment needs among adults with diabetes. The simplicity of the model used in this study allows it to be integrated to diabetes programmes in particular in countries with a developing health care system.

Impact of dental insurance on adults’ oral health care in Tehran, Iran.

The aim of the present study was to determine relationships between insurance status and utilization of oral health care and its characteristics and to identify factors related to insured patients’ selection of dental clinic or dentist. The study was based on cross-sectional data obtained through phone interviews. The target population included adults in the city of Tehran. Using a two-stage stratified random technique, 3,200 seven-digit numbers resembling real phone numbers were drawn; when calling, 1,669 numbers were unavailable (busy, no answer, fax, line blocked). Of the 1,531 subjects who answered the phone call, 224 were outside the target age (under 18), and 221 refused to respond, leaving 1,086 subjects in the final sample. The interviews were carried out using a structured questionnaire and covered characteristics of dental visits, the respondent’s reason for selecting a particular dentist or clinic and demographic and socio-economic background (gender, age, level of education, income, and insurance status). Data analysis included the Chi-square test, ANOVA, and logistic regression and the corresponding odds ratios (OR). Of all the 1,086 respondents, 57% were women, 62% were under age 35, 46% had a medium and 34% a high level of education, 13% were under the poverty line, and 70% had insurance coverage; 64% with the public, and 6% with a commercial insurance. Having insurance coverage was more likely for women (OR=1.5), for those in the oldest age group (OR=2.0), and for those with a high level of education (OR=2.5). Of those with dental insurance, 54% reported having had a dental visit within the past 12 months ; more often by those with commercial insurance in comparison with public (65% vs. 53% p<0.001). Check-up as the reason for the most recent visit occurred most frequently among those with commercial insurance (28%) compared with those having public insurance (16%) or being non-insured (13%) (p<0.001). Having had two or more dental visits within the past 12 months was most common among insured respondents, when compared with the non-insured (31% vs. 22% p=0.01). The non-insured respondents reported tooth extractions almost twice as frequently as did the insured ones (p<0.001). Of the 726 insured subjects, 60% selected fully out-of-pocket-paid services (FOP), and 53% were unaware of their insurance benefits. Of those who selected FOP, good interpersonal aspects (OR=4.6), being unaware of dental insurance benefits (OR=4.6), and good technical aspects (OR=2.3) as a reason had greater odds of selecting FOP. The present study revealed that dental insurance was positively related to demand for oral health care as well as to utilization of services, but to the latter with a minor extent. Among insured respondents, despite their opportunity to use fully or highly subsidized oral health care services, good interpersonal relationship and high quality of services were the most important factors when an insured patient selected a dentist or a clinic. The present findings indicate a clear need to modify dental insurance systems in Iran to facilitate optimal use of oral health care services to maximize the oral health of the population. A special emphasis in the insurance schemes should be focused on preventive care.

Oral health behaviour, conditions and care among dentate elderly patients in Lithuania: preventive aspects

The present cross-sectional study aimed to assess oral health behaviour, dental and periodontal conditions, dental care, and their relationships among elderly dentate patients in Lithuania. The target population in the study were dentate patients aged 60 and older attending public dental services in Kedainiai, Lithuania. The data collection took place between the autumn of 1999 and the winter of 2001. Data were collected by means of a self-administered questionnaire for all (n=174) and a clinical examination targeting about half of the subjects (n=100). The questionnaire inquired about oral health behaviour, the life-first and also the most recent dental treatments, sources on and self-assessed knowledge of oral self-care, a self-reported number of teeth, and socio-demographic information. The clinical examination included basic dental and periodontal conditions. A total of 82 women and 92 men completed the questionnaire; their mean age was 69.2 and their average number of teeth was 16.2 (CI 95% 15.4-17.1). In all, 25% had 21 or more teeth and 32% indicated wearing removable dentures. The oral health behaviour, the participants reported, was poor: 30% reported twice daily toothbrushing, 57% responded that they always use fluoride toothpaste, 19% indicated daily interdental cleaning, nearly all said they take sugar in their coffee and tea, and 30% indicated going for check-ups. As the main source of information on oral self-care, the subjects indicated health professionals (82%), followed by social contacts (72%), broadcasted media (58%), and printed media (42%). A total of 34% assessed their knowledge of oral self-care as good, and their self-assessed knowledge correlated (r=0.52) with professional guidance they had received about oral self-care. In their most recent treatment, conservative (39%) and non-conservative (34%) treatments dominated, and preventive ones were the least reported (7%). Regarding guidance in oral self-care, 54% reported having received such about toothbrushing, 32% about interdental cleaning, and 33% had been given visual information. Clinical examinations revealed the presence of plaque, calculus, bleeding on probing and deepened pockets in all of the subjects; 70% of the subjects were diagnosed with pockets of 6mm and deeper, 94% with caries, and 73% with overhangs of restorations. Those subjects assessing their knowledge of oral self-care as good and reporting a higher intensity of guidance in oral self-care as received, indicated practicing the recommended oral self-care more frequently. Twice daily toothbrushing was associated with good self-assessed knowledge of oral self-care (OR 4.1, p<0.001) and a university education (OR 5.6, p<0.001). Those subjects with better oral health behaviour had a greater number of teeth. Having 21 or more teeth was associated with good self-assessed knowledge of oral self-care (OR 4.1, p=0.03). Better periodontal conditions were associated with a higher frequency of toothbrushing. The presence of periodontal pockets of 6mm and deeper was associated with the level of self-assessed knowledge of oral self-care being below good (OR=3.0, p=0.04) and the level of dental cleanliness being poor (OR=2.7, p=0.02). To conclude, oral health behaviour and conditions call for improvement in elderly subjects in Lithuania. To improve the oral health of their elderly dentate patients, dentists should apply all the available tools of chair-side prevention and active guidance. The latter would be an effective means of updating the knowledge of oral self-care and supporting recommended oral health behaviour. A preventive approach should be strongly emphasized in countries with limited resources for oral health care, such as Lithuania. Author’s address: Sonata Vyšniauskaite, Department of Oral Public Health, Institute of Dentistry, University of Helsinki, P.O.Box 41, FI-00014 Helsinki, Finland. E-mail: sonata.vysniauskaite@helsinki.fi

Restorative treatment practices and dentist-related factors

This study aimed at elucidating real-life aspects of restorative treatment practices. In addition, dentists' views and perceptions of and variation in restorative treatment practices with respect to dentist-related factors were evaluated. Reasons for placement and replacement of restoration, material selection, posterior restoration longevity, and the use of local anesthesia were assessed on two cross-sectional data sets. Data from the Helsinki Public Dental Service (PDS) included details on 3057 restorations performed by dentists (n=134) during routine clinical work in 2001. The other PDS data from Vantaa were based on 205 patient records of young adults containing information on 1969 restorations investigated retrospectively from 1994-1996 backwards; 51 dentists performed the restorations. In addition, dentists’ self-reported use of local anesthesia and estimates of restoration longevity were investigated by means of a nationwide questionnaire sent to 592 general dental practitioners selected by systematic sampling from the membership list of the Finnish Dental Association in 2004. All data sets included some background information on dentists such as gender, year of birth or graduation, and working sector. In PDS in 2001, primary caries was the reason for placement of restoration more often among patients aged under 19 years than among older patients (p<0.001). Among patients over 36 years of age, replacements represented the majority. Regarding dentist-related factors, replacements of restorations were made by younger dentists more frequently than by older dentists (p<0.001). In PDS in 1994-1996, the replacement rate of posterior restorations was greater among female dentists than among male dentists (p=0.01), especially for amalgams (p=0.008). The mean age of replaced posterior restoration among young adults was 8.9 (SD 5.2) years for amalgam and 2.4 (SD 1.4) years for tooth-colored restorations, the actual replacement rate for all existing posterior restorations being 7% in PDS in 1994-1996. Of all restorative materials used, a clear majority (69%) were composites in PDS in 2001. Local anesthesia was used in 48% of cases and more frequently for older patients (55%) than for patients aged under 13 years (35%) (p<0.001). Younger dentists more often used local anesthesia for primary restoration than did the older dentists (p<0.001), especially for primary teeth (p=0.005). Working sector had an impact on dentists’ self-reported use of local anesthesia and estimates of restoration longevity; public sector dentists reported using local anesthesia more frequently than private sector dentists for Class II (p=0.04) and for Class III restorations (p=0.01). Private sector dentists gave longer estimates of posterior composite longevity than public sector dentists (p=0.001). In conclusion, restorative treatment practices seem to vary according to patient age and also dentist-related factors. Replacements of restorations are common for adults. For children, clear underuse of local anesthesia prevails.

Sostdc1 Plays an Essential Role in Mammalian Tooth Patterning : Insight into the Rodent Dental Evolution

This thesis work focuses on the role of TGF-beta family antagonists during the development of mouse dentition. Tooth develops through an interaction between the dental epithelium and underlying neural crest derived mesenchyme. The reciprocal signaling between these tissues is mediated by soluble signaling molecules and the balance between activatory and inhibitory signals appears to be essential for the pattern formation. We showed the importance of Sostdc1 in the regulation of tooth shape and number. The absence of Sostdc1 altered the molar cusp patterning and led to supernumerary tooth formation both in the molar and incisor region. We showed that initially, Sostdc1 expression is in the mesenchyme, suggesting that dental mesenchyme may limit supernumerary tooth induction. We tested this in wild-type incisors by minimizing the amount of mesenchymal tissue surrounding the incisor tooth germs prior to culture in vitro. The cultured teeth phenocopied the extra incisor phenotype of the Sostdc1-deficient mice. Furthermore, we showed that minimizing the amount of dental mesenchyme in cultured Sostdc1-deficient incisors caused the formation of additional de novo incisors that resembled the successional incisor development resulting from activated Wnt signaling. Sostdc1 seemed to be able to inhibit both mesenchymal BMP4 and epithelial canonical Wnt signaling, which thus allows Sostdc1 to restrict the enamel knot size and regulate the tooth shape and number. Our work emphasizes the dual role for the tooth mesenchyme as a suppressor as well as an activator during tooth development. We found that the placode, forming the thick mouse incisor, is prone to disintegration during initiation of tooth development. The balance between two mesenchymal TGF-beta family signals, BMP4 and Activin is essential in this regulation. The inhibition of BMP4 or increase in Activin signaling led to the splitting of the large incisor placode into two smaller placodes resulting in thin incisors. These two signals appeared to have different effects on tooth epithelium and the analysis of the double null mutant mice lacking Sostdc1 and Follistatin indicated that these TGF-beta inhibitors regulate the mutual balance of BMP and Activin in vivo. In addition, this work provides an alternative explanation for the issue of incisor identity published in Science by Tucker et al. in 1998 and proposes that the molar like morphology that can be obtained by inhibiting BMP signaling is due to partial splitting of the incisor placodes and not due to change in tooth identity from the incisor to the molar. This thesis work presents possible molecular mechanisms that may have modified the mouse dental pattern during evolution leading to the typical rodent dentition of modern mouse. The rodent dentition is specialized for gnawing and consists of two large continuously growing incisors and toothless diastema region separating the molars and incisors. The ancestors of rodents had higher number of more slender incisors together with canines and premolars. Additionally, murine rodents, which include the mouse, have lost their ability for tooth replacement. This work has revealed that the inhibitory molecules appear to play a role in the tooth number suppression by delineating the spatial and temporal action of the inductive signals. The results suggest that Sostdc1 plays an essential role in several stages of tooth development through the regulation of both the BMP and Wnt pathway. The work shows a dormant sequential tooth forming potential present in wild type mouse incisor region and gives a new perspective on tooth suppression by dental mesenchyme. It reveals as well a novel mechanism to create a large mouse incisor through the regulation of mesenchymal balance between inductive and inhibitory signals.