Current Guidance for Fluoride Intake: Is It Appropriate?

The purpose of this report is to examine critically the appropriateness of the current guidance for fluoride intake in the population (0.05-0.07 mg F/kg bodyweight/d), consider whether changes to the current guidance are desirable, and suggest further research that will strengthen the evidence base for future decisions on guidance/advice in this area. The benefits and the risks of using fluoride particularly concern preschool children because it is at this age that excessive fluoride intake may result in dental fluorosis. Data from mostly cross-sectional studies show a wide variation in exposure and a considerable variation in the amount of fluoride ingested. Fluorosis, mostly mild, is commonly observed. For considering changes in current guidance, there is a need for more knowledge on the relationship between exposure to fluoride at an early age and the development of fluorosis. For that, prospective epidemiological studies with sufficiently large and representative samples of children are required. It is also important to study children in communities both with and without water fluoridation and to include populations where salt or milk fluoridation is used. There is also a need for professional agreement on acceptable levels of mild and moderate/severe fluorosis and a more comprehensive knowledge on the appreciation of mild fluorosis among the public.

Estimates of sensitivity and specificity of electric pulp testing depend on pulp disease spectrum: a modelling study.

AIM: To demonstrate how the spectrum of diseased pulps may influence sensitivity and specificity in diagnostic studies on pulp status. METHODOLOGY: An original sample from a previous study consisting of 59 teeth scheduled for root canal treatment was used where the relationship between the response to electric pulp testing and the visual status of the pulp was evaluated. To alter the spectrum of diseased pulps, a hypothetical sample of asymptomatic teeth with deep caries lesions was added to the original sample. Sensitivity and specificity were then compared for the two samples. RESULTS: In the original sample of 59 teeth, sensitivity was 72% and specificity 90%. When the spectrum of diseased pulps was altered, sensitivity decreased to 67% and specificity increased to 97%. The change in disease spectrum also decreased the prevalence of necrotic pulps. CONCLUSIONS: The spectrum of diseased pulps included in a diagnostic study on the accuracy of electric pulp testing, and indirectly also disease prevalence (here pulp necrosis), influences estimates of sensitivity and specificity. This implies that estimates of diagnostic accuracy from one study with a particular tooth population spectrum may not apply to another tooth population with a different disease spectrum.

Limited evidence for the use of imaging to detect prostate cancer: a systematic review.

OBJECTIVE: To assess the diagnostic accuracy of imaging technologies for detecting prostate cancer in patients with elevated PSA-values or suspected findings on clinical examination. METHODS: The databases Medline, EMBASE, Cochrane, CRD HTA/DARE/NHS EED and EconLit were searched until June 2013. Pre-determined inclusion criteria were used to select full text articles. Risk of bias in individual studies was rated according to QUADAS or AMSTAR. Abstracts and full text articles were assessed independently by two reviewers. The performance of diagnostic imaging was compared with systematic biopsies (reference standard) and sensitivity and specificity were calculated. RESULTS: The literature search yielded 5141 abstracts, which were reviewed by two independent reviewers. Of these 4852 were excluded since they did not meet the inclusion criteria. 288 articles were reviewed in full text for quality assessment. Six studies, three using MRI and three using transrectal ultrasound were included. All were rated as high risk of bias. Relevant studies on PET/CT were not identified. CONCLUSION: Despite clinical use, there is insufficient evidence regarding the accuracy of imaging technologies for detecting cancer in patients with suspected prostate cancer using TRUS guided systematic biopsies as reference standard.

Caries risk assessment. A systematic review.

OBJECTIVE: To assess the ability of multivariate models and single factors to correctly identify future caries development in pre-school children and schoolchildren/adolescents. STUDY DESIGN: A systematic literature search for relevant papers was conducted with pre-determined inclusion criteria. Abstracts and full-text articles were assessed independently by two reviewers. The quality of studies was graded according to the QUADAS tool. The quality of evidence of models and single predictors was assessed using the GRADE approach. RESULTS: Ninety original articles fulfilled the inclusion criteria. Seven studies had high quality, 35 moderate and the rest poor quality. The accuracy of multivariate models was higher for pre-school children than for schoolchildren/adolescents. However, the models had seldom been validated in independent populations, making their accuracy uncertain. Of the single predictors, baseline caries experience had moderate/good accuracy in pre-school children and limited accuracy in schoolchildren/adolescents. The period of highest risk for caries incidence in permanent teeth was the first few years after tooth eruption. In general, the quality of evidence was limited. CONCLUSIONS: Multivariate models and baseline caries prevalence performed better in pre-school children than in schoolchildren/adolescents. Baseline caries prevalence was the most accurate single predictor in all age groups. The heterogeneity of populations, models, outcome criteria, measures and reporting hampered the synthesis of results. There is a great need to standardize study design, outcome measures and reporting of data in studies on caries risk assessment. The accuracy of prediction models should be validated in at least one independent population.

Radiological diagnosis of periapical bone tissue lesions in endodontics: a systematic review.

This systematic review evaluates the diagnostic accuracy of radiographic methods employed to indicate presence/absence and changes over time of periapical bone lesions. Also investigated were the leads radiographic images may give about the nature of the process and the condition of the pulp in nonendodontically treated teeth. Electronic literature search included the databases PubMed, Embase and CENTRAL from January 1950 to June 2011. All languages were accepted provided there was an abstract in English. The MeSH terms were 'Cone beam computed tomography (CBCT)', 'Radiography, panoramic', 'Periapical diseases', 'Dental pulp diseases', 'Sensitivity and specificity', 'receiver operating characteristics (ROC) curve', 'Cadaver', 'Endodontics' and 'Radiography dental'. Two reviewers independently assessed abstracts and full text articles. An article was read in full text if at least one of the two reviewers considered an abstract to be potentially relevant. Altogether, 181 articles were read in full text. The GRADE approach was used to assess the quality of evidence of each radiographic method based on studies of high or moderate quality. Twenty-six studies fulfilled criteria set for inclusion. None was of high quality; 11 were of moderate quality. There is insufficient evidence that the digital intraoral radiographic technique is diagnostically as accurate as the conventional film technique. The same applies to CBCT. No conclusions can be drawn regarding the accuracy of radiological examination in identifying various forms of periapical bone tissue changes or about the pulpal condition.

Diagnosis of the condition of the dental pulp: a systematic review.

The aim of this systematic review was to appraise the diagnostic accuracy of signs/symptoms and tests used to determine the condition of the pulp in teeth affected by deep caries, trauma or other types of injury. Radiographic methods were not included. The electronic literature search included the databases PubMed, EMBASE, The Cochrane Central Register of Controlled Trials and Cochrane Reviews from January 1950 to June 2011. The complete search strategy is given in an Appendix S1 (available online as Supporting Information). In addition, hand searches were made. Two reviewers independently assessed abstracts and full-text articles. An article was read in full text if at least one of the two reviewers considered an abstract to be potentially relevant. Altogether, 155 articles were read in full text. Of these, 18 studies fulfilled pre-specified inclusion criteria. The quality of included articles was assessed using the QUADAS tool. Based on studies of high or moderate quality, the quality of evidence of each diagnostic method/test was rated in four levels according to GRADE. No study reached high quality; two were of moderate quality. The overall evidence was insufficient to assess the value of toothache or abnormal reaction to heat/cold stimulation for determining the pulp condition. The same applies to methods for establishing pulp status, including electric or thermal pulp testing, or methods for measuring pulpal blood circulation. In general, there are major shortcomings in the design, conduct and reporting of studies in this domain of dental research.

Unrestored dentin caries and deep dentin restorations in Swedish adolescents.

The objectives of this longitudinal study were to assess: (a) the prevalence of unrestored dentin caries among 15-year-olds, (b) the proportion of these lesions that had progressed to deep dentin lesions (inner half of dentin) since the immediately preceding examination at the age of 14 and (c) the frequency of deep restorations (extending into the inner half of the dentin). The sample consisted of all 15-year-olds (n = 2,487) born in 1990 and included in the Public Dental Service in Malmo, Sweden. Bitewing radiographs taken during 2005-2007 and the immediately preceding radiographs were analysed and scored by two examiners. The main radiographic scores were: sound; radiolucency in the outer or inner half of dentin; restored surface. The results showed that 22% of the individuals had 1 or more dentin lesions left unrestored from the time of the examination at the age of 14 until the next recall examination at the age of 15. During the observation period (median time 1.2 years), 9% of the unrestored outer dentin lesions progressed to deep dentin lesions. The majority of these (93%) were in molars. One or more deep restorations were found in 22% of the 15-year-olds; the majority involved occlusal surfaces of first molars. In conclusion, unrestored dentin lesions were common in 15-year-olds. Progression to deep dentin lesions occurred in 9% of these lesions and was most common in first molars. Occlusal surfaces of first molars had the highest frequency of deep restorations.

Detection of approximal caries by clinical and radiographic examination in 9-year-old Swedish children.

The aims were to determine caries prevalence in 9-year-olds belonging to a low-caries prevalence population and to assess how accurately some commonly used risk factors/risk markers (predictors) can identify additional approximal caries as judged from bitewing examination (BW). One calibrated dentist examined 117 consecutive 9-year-olds from the inner city of Stockholm. The predictors were the number of clinically detected dfs and DFS, visible plaque, salivary mutans streptococci, tooth brushing habits, consumption of sugary products, parents' education, and (before BW) an overall clinical judgement by the examiner. Analyses of the data included sensitivity and specificity and a multiple logistic regression model. When BW was included, the mean DFS was 0.27 and the mean dfs 1.74. For approximal enamel and dentin lesions, the average gain from BW was 0.20 lesions for permanent first molars and 1.23 lesions for primary molars. Altogether, 48% of the children benefited from BW. The best predictors of additional approximal caries from BW were presence of caries (cavitation/dentin level) on occlusal surfaces of permanent first molars and the dentist's judgement based on clinical findings, both with a combined sensitivity and specificity of 134%. The only statistically significant variables in a logistic regression model were the dentist's judgement and the child's statement about regular tooth brushing. It is concluded that a sizeable proportion of 9-year-olds, representing a low-caries prevalence population, benefited from BW. However, the ability to identify these children from the predictors was limited.

Detection of approximal caries in 5-year-old Swedish children.

The aim was to assess how accurately some commonly used risk factors/risk markers (predictors) for caries development could identify children with and without approximal caries as judged from bitewing radiography. Two hundred and sixty-seven consecutive 5-year-old children from two Swedish cities participated. Three experienced dentists examined the children. The predictors were the overall dmfs (decayed, missing and filled surfaces) value (canines and molars), the number of occlusal dmfs, the frequency of intake of between-meal sugary products, visible plaque on free smooth surfaces of second primary molars, toothbrushing habits and (before bitewing examination) an overall judgement by the examining dentist. The mean dmfs value without bitewing examination was 0.40 (SD = 1.22). Twelve percent of the children had at least one dentin lesion and 33% at least one enamel lesion that were detected from bitewing examination only. The gain from adding bitewing examination to clinical examination amounted to a mean of 1.2 approximal enamel and/or dentin lesions. The ability to correctly identify children with approximal caries from the predictors was limited; sensitivity ranged from 0.27 to 0.75 and specificity ranged from 0.41 to 0.93. The single best predictor was the dentist's overall judgement with an average precision of 73%; average sensitivity for the presence of enamel and dentin lesions was 0.48 and for the presence of dentin lesions 0.66. The rest of the predictors added little to the predictive power. It is concluded that 33% of the 5-year-olds, representing a low caries prevalence population, benefited from bitewing examination. The ability to identify these children from the predictors was, however, limited.

Hypomineralized molars and incisors of unknown origin: treatment outcome at age 18 years.

OBJECTIVE: To assess the outcome of treatment of hypomineralized molars and incisors of unknown aetiology (MIH) in 18-year-olds. DESIGN: A follow-up study including clinical examination, panoramic radiography and intraoral photos. SAMPLE AND METHOD: Seventy-six individuals treated at the Eastman Dental Institute in Stockholm during 1978-2001 with the diagnosis MIH. Severity of enamel defects in molars and incisors, prevalence and distribution of extracted molars, type, quality and median duration of restorations, periradicular condition of affected molars, dental occlusion and space closure in cases of extraction, as well as the individual's satisfaction with the treatment, were assessed. RESULTS: Severe defects with enamel surface breakdown in all four molars occurred in 42% of the individuals and 29% had at least one incisor with yellow/brown opacity in the enamel. At follow up, 42% of the individuals had at least one molar extracted; 18% had all four molars extracted. The median duration of the molar restorations (n = 153) was 5 years. Of the individuals with restored molars, 48% had at least one unacceptable restoration. Periradicular pathology was observed in three molars. The sagittal relations did not differ between individuals with and without extraction of molars. Space closure was acceptable in 87% of the individuals with extracted molars. Eighty percent were satisfied with the treatment. CONCLUSIONS: Extraction of molars with severe enamel defects gave good or acceptable results in a majority of the patients while conservative restorative treatment resulted in a need for additional treatment in approximately half of the patients.

Conservative endodontic treatment of teeth fractured in the middle or apical part of the root.

According to treatment type, root-fractured teeth with pulp necrosis or exposed pulps were divided into five groups, group 1: 17 teeth in which the root canal of the coronal fragment only was filled with gutta-percha (GP); group 2: seven teeth in which the root canals of the coronal and apical fragments were both filled with GP; group 3: 19 teeth in which the coronal fragment was filled with GP and the apical fragment was surgically removed; group 4: 68 teeth where the root canal of the coronal fragment was treated with calcium hydroxide and subsequently filled with GP; and group 5: five vital teeth with root and concomitant crown fractures in which the exposed pulps were treated by partial pulpotomy. The frequency of periodontal healing was 76% in group 1, zero in group 2, 68% in group 3 and 86% in group 4. Compared with groups 1 and 2 combined, healing in group 4 was significantly more frequent. In groups 1, 2 and 4, failures occurred significantly more often in teeth showing overfilling, i.e. protrusion of GP into the space between the fragments, compared with teeth without overfilling. All five teeth in group 5 showed healing. It was concluded that root canal filling with GP of the coronal fragment only, with or without surgical removal of the apical fragment, can be successful in selected cases. Treatment of the root canal with calcium hydroxide followed by GP filling appears to be the treatment of choice in root-fractured non-vital teeth. Partial pulpotomy of exposed pulps in five teeth showed results similar to root-unfractured teeth with pulp exposure treated with this technique.

Healing of 400 intra-alveolar root fractures. 1. Effect of pre-injury and injury factors such as sex, age, stage of root development, fracture type, location of fracture and severity of dislocation.

This retrospective study consisted of 400 root-fractured, splinted or non-splinted incisors in young individuals aged 7-17 years (mean = 11.5 +/- 2.7 SD) who were treated in the period 1959-1995 at the Department of Pediatric Dentistry, Eastman Dental Institute, Stockholm. Four hundred of these root fractures were diagnosed at the time of injury; and 344 teeth were splinted with either cap-splints, orthodontic appliances, bonded metal wires, proximal bonding with composite resin or bonding with a Kevlar or glass fiber splint. In 56 teeth, no splinting was carried out for various reasons. In the present study, only pre-injury and injury factors were analyzed. In a second study, treatment variables will be analyzed. The average observation period was 3.1 years +/- 2.6 SD. The clinical and radiographic findings showed that 120 teeth out of 400 teeth (30%) had healed by hard tissue fusion of the fragments. Interposition of periodontal ligament (PDL) and bone between fragments was found in 22 teeth (5%), whereas interposition of PDL alone was found in 170 teeth (43%). Finally, non-healing, with pulp necrosis and inflammatory changes between fragments, was seen in 88 teeth (22%). In a univariate and multivariate stratified analysis, a series of clinical factors were analyzed for their relation to the healing outcome with respect to pulp healing vs. pulp necrosis and type of healing (hard tissue vs. interposition of bone and/or PDL or pulp necrosis). Young age, immature root formation and positive pulp sensibility at the time of injury were found to be significantly and positively related to both pulpal healing and hard tissue repair of the fracture. The same applied to concussion or subluxation (i.e. no displacement) of the coronal fragment compared to extrusion or lateral luxation (i.e. displacement). Furthermore, no mobility vs. mobility of the coronal fragment. Healing was progressively worsened with increased millimeter diastasis between fragments. Sex was a significant factor, as girls showed more frequent hard tissue healing than boys. This relationship could possibly be explained by the fact that girls experienced trauma at an earlier age (i.e. with more immature root formation) and their traumas were of a less severe nature. Thus, the pre-injury or injury factors which had the greatest influence upon healing (i.e. whether hard tissue fusion or pulp necrosis) were: age, stage of root development (i.e. the size of the pulpal lumen at the fracture site) and mobility of the coronal fragment, dislocation of the coronal fragment and diastasis between fragments (i.e. rupture or stretching of the pulp at the fracture site).

Healing of 400 intra-alveolar root fractures. 2. Effect of treatment factors such as treatment delay, repositioning, splinting type and period and antibiotics.

This is the second part of a retrospective study of 400 root-fractured permanent incisors. In this article, the effect of various treatment procedures is analyzed. Treatment delay, i.e. treatment later than 24 h after injury, did not change the root fracture healing pattern, healing with hard tissue between fragments (HH1), interposition of bone and/or periodontal ligament (PDL) or pulp necrosis (NEC). When initial displacement did not exceed 1 mm, optimal repositioning appeared to significantly enhance both the likelihood of pulpal healing and hard tissue repair (HH1). Significant differences in healing were found among the different splinting techniques. The lowest frequency of healing was found with cap splints and the highest with fiberglass or Kevlar splints. The latter splinting procedure showed almost the same healing result as non-splinting. Comparison between non-splinting and splinting for non-displaced teeth was found to reveal no benefit from splinting. With respect to root fractures with displacement, too few cases were available for analysis. No beneficial effect of splinting periods greater than 4 weeks could be demonstrated. The administration of antibiotics had the paradoxical effect of promoting both HH1 and NEC. No explanation could be found. It was concluded that, optimal repositioning seems to favor healing. Furthermore, the chosen splinting method appears to be related to healing of root fractures, with a preference to pulp healing and healing fusion of fragments to a certain flexibility of the splint and possibly also non-traumatogenic splint application. Splinting for more than 4 weeks was not found to influence the healing pattern. A certain treatment delay (a few days) appears not to result in inferior healing. The role of antibiotics upon fracture healing is questionable.

Caries incidence and lesion progression from adolescence to young adulthood: a prospective 15-year cohort study in Sweden.

The objectives were (1) to assess caries development, including the incidence and rate of lesion progression, in a Swedish cohort from adolescence to young adulthood and (2) to compare the caries incidence rates in adolescents with those of young adults. The original material consisted of 536 children aged 11-13 years at baseline. This cohort had been followed through annual bitewing radiographs to 21-22 years of age. In 1998-1999, 250 of these individuals were re-examined at the age of 26-27, and the new caries data were added to the original data. The results showed that fewer new enamel lesions developed on approximal surfaces during young adulthood than during adolescence; the caries incidence rates for enamel lesions decreased from 4.3 in the age group 12-15 years to 2.7 new caries lesions/100 surface-years in the age group 20-27 years. The same applied to the rate of lesion progression, where the corresponding values from the enamel-dentin border to the outer dentin were 32.5 for the youngest and 10.9 new lesions/100 surface-years for the oldest age group. The caries incidence of outer dentin lesions on approximal surfaces was low but increased from 0.2 in the age group 12-15 years to 0.9 new outer dentin lesions/100 surface-years in the age group 20-27 years. The incidence rates varied considerably between different tooth surfaces. Also for occlusal surfaces, fewer new dentin lesions developed during young adulthood than during adolescence; the incidence was 2.0 new dentin lesions/100 surface-years in the youngest age group and 0.7 during young adulthood. At the age of 13, the proportion of DFS of occlusal surfaces predominated over DFS of approximal surfaces but at the age of 26-27 the proportions of occlusal and approximal DFS were almost equal.

Judgement criteria for molar incisor hypomineralisation (MIH) in epidemiologic studies: a summary of the European meeting on MIH held in Athens, 2003.

AIM: This paper reviews the proceedings and conclusions of a meeting of experts concerned with the problem of hypomineralised incisors and molars (MIH). The aims of this meeting were to establish criteria for the judgement of MIH, to select representative cases and to discuss how the name of the condition was best described as hypomineralised, or hypomaturated, first permanent molars. CONCLUSION: There was not complete agreement as to the correct diagnosis and aetiology of the condition. A suggested list of definitions of the judgement criteria to be used in diagnosing Molar Incisor Hypomineralisation (MIH) for prevalence studies was agreed upon.

EAPD guidelines for use of radiographs in children.

Guidelines in dental radiology are designed to avoid unnecessary exposure to X-radiation and to identify individuals who may benefit from a radiographic examination. Every prescription of radiographs should be based on an evaluation of the individual patient benefit. Due to the relatively high frequency of caries among 5 year old children it is recommended to consider dental radiography for each child even without any visible caries or restorations. Furthermore, radiography should be considered at 8-9 years of age and then at 12-14, that is 1-2 years after eruption of premolars and second molars. Additional bitewing controls should be based on an overall assessment of the caries activity/risk. The high-risk patient should be examined radiographically annually, while a 2-3 years interval should be considered when caries activity/risk is low. Routine survey by radiographs, except for caries, has not been shown to provide sufficient information to be justified considering the balance between cost (radiation and resources) and benefit.

Conventional versus resin-modified glass-ionomer cement for Class II restorations in primary molars. A 3-year clinical study.

OBJECTIVE: To compare the clinical performance of two glass-ionomer cements (GICs)for Class II restorations in primary molars: a conventional cement (Fuji II) and a resin-modified cement (Vitremer). DESIGN: Split mouth and random assignment to the two materials were used for the majority of the molars. SAMPLE AND METHODS: Forty consecutive 4-7-year-old children were included. One operator made 115 restorations: 53 with Vitremer and 62 with Fuji II. The restorations were evaluated clinically, radiographically and from colour photographs. RESULTS: The cumulative success rate of the Vitremer restorations was 94% and that of the Fuji II restorations 81%. The difference is statistically significant. The risk of a failed restoration was more than five times higher with Fuji II than with Vitremer as the restorative material. Of the 13 unsuccessful restorations, seven had lost their retention, four had secondary caries, and two were fractured. CONCLUSIONS: The resin-modified GIC offered advantages over the conventional GIC for restoring approximal caries in primary molars.

Molar incisor hypomineralization: a questionnaire inventory of its occurrence in member countries of the European Academy of Paediatric Dentistry (EAPD).

OBJECTIVES: The objectives were to find out whether hypomineralized permanent first molars and incisors, known as Molar Incisor Hypomineralization (MIH), occurs all over Europe, whether its prevalence in each country is known and whether or not it is considered to be a clinical problem. SAMPLE AND METHODS: Clinical photos of MIH and a five-item questionnaire were sent to members of the European Academy of Paediatric Dentistry (EAPD). A total of 59 questionnaires were sent to members in 31 countries. After one month a reminder was sent to non-responders. RESULTS: Fifty-four dentists (92%) in 30 countries (97%) returned the questionnaire. MIH was stated to occur in all but one country (the Czech Republic). Nearly all the responders (97%) stated that they were familiar with the clinical appearance of MIH and a majority saw it as a clinical problem. Furthermore, a large majority of the responders (90%) considered it important to map the prevalence of MIH in European countries as such data are available to only a limited extent. CONCLUSION: Paediatric dentists in Europe are aware of MIH and the majority consider it to be a clinical problem. Only limited data are available on the prevalence of MIH. Comparable and representative prevalence studies are therefore urgently needed to gain more knowledge about the magnitude of MIH and related clinical problems.

Caries rates related to approximal caries at ages 11-13: a 10-year follow-up study in Sweden.

Predicting future caries risk is a difficult but important clinical task. The aim of this study was to analyze radiographically the relationship between approximal caries (4d-7m) at ages 11-13 (baseline) and future approximal caries. We followed 534 individuals prospectively through annual bitewing radiographs from 11 to 22 years of age. Two measures were used: individual-based incidence of the first new approximal caries lesion and surface-based incidence of approximal lesions. In the group with no approximal caries lesions at baseline, the individual-based incidence was 19 first new approximal lesions/100 person-years; the corresponding value for those with 3 approximal lesions at baseline was 71. Individuals with no approximal lesions at baseline developed 3.1 new lesions/100 tooth surface-years; the corresponding value for those with 3 lesions at baseline was 7.7. The highest risk for developing new approximal lesions was within the first 2 years after baseline.

Influence of approximal caries in primary molars on caries rate for the mesial surface of the first permanent molar in swedish children from 6 to 12 years of age.

The objective was to assess the influence on the caries rate for the mesial surface of the first permanent molar (6m) of the caries status of the distal surface of the second primary molar (05d) in children from 6 to 12 years of age. The study design was retrospective and included 374 children with an average of 5 sets of bite-wing radiographs. The mean age of the children was 6.7 years when the first bite-wing radiographs were taken and 11.5 years at the time of the latest radiographs included in the study. The approximal surfaces were classified according to a scoring system: 0 = no visible radiolucency, 1= radiolucency in the outer half of the enamel, 2 = radiolucency in the inner half up to the enamel-dentin border, 3 = radiolucency with a broken enamel-dentin border but with no obvious involvement of the dentin, 4 = radiolucency with obvious spread in the outer half of the dentin, and score 5 = radiolucency in the inner half of the dentin. The influence of the status of 05d on the caries rate for 6m (state > or =2) was assessed by using a model for dependence between the two neighbouring surfaces. Presence or absence of approximal caries in the distal surface of the first primary molars (04d) and/or the mesial surface of the second primary molars (05m) at the time of eruption of 6m was also related to the caries rate for 6m. The caries rate for 6m was 15 times higher if 05d had developed enamel/enamel-dentin border caries (state 2 or 3) compared to a radiographically sound 05d (state 0 or 1). No significant increase in the caries rate for 6m was found when 05d had deeper unrestored dentin caries than when 05d had superficial caries (state 2 or 3). Furthermore, for preventing caries in 6m, no benefit could be found from restoring an 05d with dentin caries with amalgam as opposed to leaving the carious lesion unrestored until exfoliation. The caries rates for 6m and 05d were 3.4 and 2.7 times higher, respectively, in the presence of dentin caries/restoration in 04d/05m compared to absence of dentin caries in these molar surfaces at the time of eruption of 6m. In conclusion, the caries rate for 6m depended on the status of 05d and increased 15 times if 05d had enamel/enamel-dentin border caries compared to a sound 05d. Deeper unrestored or restored dentin lesions in 05d did not result in a higher caries rate for 6m compared with more shallow carious lesions in 05d.