Effects of glucocorticoids upon the glycosaminoglycans in salivary glands in the rat

The glycosaminoglycans of the salivary glands were studied in male rats after adrenalectomy and after the daily administration of either 100 or 300 μg of cortisol acetate to adrenalectomized rats during one month. Total uronic acid concentration was determined in the salivary glands. Chromatographic separation of the uronic acid fractions was performed on cellulose microcolumns. Adrenalectomy decreased the uronic acid concentration in the submaxillary and retrolingual glands, while the administration of cortisol acetate increased its concentration in these glands. No changes were detected in the uronic acid concentration in the parotid glands. Adrenalectomy affected the glycoprotein, hyaluronic acid and dermatan sulphate fractions, while cortisol acetate affected the hyaluronic acid, chondroitin-4-sulphate and chondroitin-6-sulphate fractions.     

Variations in number and morphology of permanent teeth in 7-year-old Swedish children

Summary. Objectives . To establish the prevalence of numerical and morphological variations of permanent teeth in Swedish 7-year-olds and to accept or reject the hypothesis of a higher prevalence for these conditions in northern Sweden compared to other areas.
Design . Cross-sectional.
Setting . Department of Odontology/Pedodontics, Umeå University, Sweden.
Sample and methods . A total of 739 healthy Caucasian 7-year-olds residing in the city of Umeå, northern Sweden in 1976. The children were examined clinically and radiographically.
Results . The prevalence of hypodontia (excluding third molars) in girls was 8·4%, in boys 6·5%, and in both sexes combined 7·4%. Of the children with hypodontia, the majority (90·9%) lacked one or two teeth. Lower second premolars were the teeth most frequently missing. The prevalence of hyperdontia was 1·9%; 11 girls and three boys were affected; 78% of the supernumerary teeth were mesiodenses. Of the morphological variations, peg-shaped upper lateral incisors were found in 0·8% of the children, double-formation (gemination) in 0·3%, taurodontism in 0·3% and dens invaginatus in 6·8%. One diagnosis was found in 18% of the children, and in almost 8% of them more than one diagnosis was found.
Conclusions . The results agree with those obtained in similar populations and are considered representative of this ethnic group. The hypothesis of a genetically determined higher prevalence of numerical and morphological variations in the study population was not verified.     

Effects of implant geometry and surface treatment on osseointegration after functional loading: a dog study

summary  The purpose of this study was to evaluate the geometry and surface characteristics of osseointegration after functional loading by radiographic, periodontal and histomorphometric analyses. We analysed three groups of implants with different geometry and surface characteristics using experimental dogs. The control group received Brånemark implants (group 1). Group 2 and group 3 implants each had a 0·5-mm pitch height but differed in surface characteristics. Group 2 implants were machine surfaced and group 3 implants were thermally oxidized at 800 °C for 2 h in a pure oxygen atmosphere. For these experiments, which used a total of four healthy beagle dogs, the implants were randomly installed into the extracted first, second and third premolar positions. The animals received radiographic and clinical periodontal examinations at 6 and 12 months post-loading, and were then killed for histomorphometric analysis. The radiographic analysis showed that mean crestal bone resorption in the control group was greater than that observed in the experimental groups ( P  < 0·05). The percentage of bone-to-implant contact for group 3 (83·7%) was significantly higher than in groups 1 (74·4%) and 2 (75·0%) ( P  < 0·05). Overall, implant geometry and surface treatment affected the rate of crestal bone resorption and bone healing surrounding the dental implants.     

Urinary fluoride excretion in children drinking fluoridated school milk

Summary. Objective . To determine fluoride excretion under various conditions of fluoride intake and to estimate the fractional urinary excretion of fluoride in individual children participating in a school milk fluoridation scheme.
Design . In the first part of the study, individual urine samples were collected from each of eight 4 to 5-year-old children for a continuous period of 55 h. For each child ( n  = 8) and for each day ( n  = 3) the maximum urinary fluoride concentration (p.p.m.F), the maximum fluoride excretion rate (μgF/h) and the total daily fluoride excretion (mg) were calculated. The second part of the study was carried out to determine the 24 h fractional percentage of fluoride excreted following administration of a known dose of fluoride in the absence of other sources.
Results . Under usual conditions of fluoride intake (i.e. milk containing 0·5 mg fluoride, customary diet and toothbrushing with fluoride toothpaste) the children's daily fluoride excretion was 0·33 mg. The fractional urinary fluoride excretion of a 0·5-mg fluoride tablet was 30%.
Conclusions . It is concluded that the children's mean 24 h fluoride excretion was somewhere between that reported in low fluoride conditions and that reported in optimally fluoridated areas. The fractional urinary fluoride excretion was found to be in agreement with the findings of other workers.     

Self-reported symptoms of temporomandibular dysfunction in a female university student population in Saudi Arabia

The symptoms of temporomandibular dysfunction (TMD), reported by 705 female university students of Riyadh, Saudi Arabia, are analysed. The population is representative of the educated class of Saudi Arabia. The most frequently reported symptoms were jaw feeling tired (34·5%), awareness of uncomfortable bite (31·3%), pain in front of the ear (22·4%) and discomfort upon wide opening (22·4%). The frequency of subjective reactions was, pain interferes with activity (42%), disturbed sleep (40·6%), taking of medication (27·8%) and pain being frustrating or depressing (26·8%). Some interesting relationships were found between the reported symptoms and marital status, residence and college of education. These findings are similar to those reported in a Bedouin community in Egypt, but lower than that in a Saudi Arabian population attending dental clinics, Saudi male dental students and high school students.     

Attitudes, awareness and oral health-related quality of life in patients with diabetes

Summary  The purpose of this study was to assess the knowledge diabetic patients have of their risk for periodontal disease, their attitude towards oral health and their oral health-related quality of life (OHRQL). One hundred and one consecutive patients (age range 31–79 years) recruited from a diabetic outpatient clinic participated in the study. Twenty-seven per cent of participants had type 1 diabetes, 66% type 2 and 7% did not know what type of diabetes they had. The length of time since participants were diagnosed as diabetic ranged from 1 to 48 years. Metabolic control of diabetes as determined by HbA1c levels ranged from 6·2% to 12·0% compared with the normal range of 4·5–6·0%. Thirty-three per cent of participants were aware of their increased risk for periodontal disease, 84% of their increased risk for heart disease, 98% for eye disease, 99% for circulatory problems and 94% for kidney disease. Half of the participants who were aware of their increased risk for periodontal disease had received this information from a dentist. Dental attendance was sporadic, with 43% reporting attendance within the last year. OHRQL was not significantly affected by the presence of diabetes in the group surveyed, in comparison with a previous survey of non-diabetic patients. A significant association was found between metabolic control and dentate status. Awareness of the potential associations between diabetes, oral health and general health needs to be increased in diabetic patients.     

Restoration of permanent teeth in young rural children in Cambodia using the atraumatic restorative treatment (ART) technique and Fuji II glass ionomer cement

Several recent studies have demonstrated the success of the ART (atraumatic restorative treatment) technique under field conditions in developing countries. The ART technique involves removal of caries using only hand instruments, and placing a glass ionomer cement (GIC) restoration.
Objectives. To estimate the longevity of Fuji II GIC ART restorations placed in permanent teeth by dental nurse students under field conditions in rural Cambodia.
Design . Clinical field trial.
Setting . One high school in rural Cambodia.
Sample and methods . 53 subjects between the ages of 12 and 17 who had dental caries were selected to participate. Subjects were randomly assigned to a dental nurse student for cavity preparation and placement of ART restorations (without cavity conditioning).
Results . 92·1% of the carious lesions required class I or class V restorations, and 85·4% were in the lower molars. 89 teeth were filled. At 1 and 3 years 86·4% and 79·5% of restorations were still present. Restorations were assessed by one dentist according to standard criteria. 76·3% of the restorations were judged to be successful at 1 year, and 57·9% at 3 years.
Conclusions . Factors which may have affected the success rates included: the material used, technical factors, failure to condition the cavity prior to restoration, and inexperience of the operators. The results suggest that ART restorations in permanent teeth using Fuji II GIC are only moderately successful after 3 years. Better results could be expected by using a dentine conditioner in conjunction with one of the newer stronger glass ionomer cements.     

Self-reported chewing side preference and its associations with occlusal, temporomandibular and prosthodontic factors: results from the population-based Study of Health in Pomerania (SHIP-0)

Summary  This study investigated the prevalence of a preferred chewing side (PCS) and associations between a PCS and signs of temporomandibular disorders (TMD), antagonist contact and prosthetic restoration. A population representative sample of 4086 adults of the cross-sectional epidemiologic 'Study of Health in Pomerania' (SHIP-0) (age range 20–80 years, female 50·2%) was divided in two groups by the presence or absence of a PCS. PCS was evaluated by a questionnaire. Chi-squared tests and multiple logistic regression were used to determine the impact of the relation between a PCS and signs and symptoms of TMD as well as dental factors. The prevalence of a PCS was 45·4%. Women between 40 and 69 years reported more frequently a PCS. There was a preference for the right side (64%). The following independent variables were significantly associated with a PCS: subjective unilateral pain in the temporomandibular joint (TMJ), odds ratio (OR) 2·4; subjective unilateral joint clicking, OR 1·7; unilateral TMJ/muscle pain on palpation, OR 1·6/OR 1·3; loss of one supporting zone (Eichner-Classification), OR 1·9; loss of both supporting zones on one side, OR 2·2, one supporting zone left, OR 1·4; presence of a removable partial denture, OR 1·6; presence of an attachment restoration, OR 1·5. A PCS was found in almost half the study population and was associated with unilateral signs of TMD, most of all TMJ pain and asymmetrical loss of antagonist contact. Despite replacement of lost teeth not all restorations seemed to support bilateral mastication.     

The relationship between sweetness preference, levels of salivary mutans streptococci and caries experience in Brazilian pre-school children

Aim . To analyse the relationship between preference for sweetness, levels of salivary mutans streptococci and levels of caries in low socio-economic 4–5-year-old Brazilian children.
Design . A cross-sectional survey.
Subjects and methods . 298 children of both sexes, who, in 1998, were regularly attending public nurseries were randomly selected. Caries experience was assessed according to WHO guidelines. Saliva samples were analysed for mutans streptococci using the spatula method. Children's preference for sugar was measured using the 'Sweet Preference Inventory'. Personal interviews with the mothers were conducted.
Results . 255 children completed all aspects of the research, a response rate of 85·6%. 34·9% of them were caries-free. The mean dmf-s was 4·25 (SD 6·16), the decayed component being 3·56 (SD 5·82) and the filled surfaces, 0·69 (SD 1·85). For these pre-school children; male sex ( P < 0·01), single parent ( P < 0·01), habit of eating or drinking items that contained non-milk extrinsic sugar between meal times ( P < 0·05) and high levels of salivary mutans streptococci ( P < 0·001) were significantly associated with higher dmfs scores. There was no statistical relationship between sweetness preference and dental caries and with mutans streptococci levels.
Conclusion . Levels of salivary mutans streptococci but not sweetness preference were potential good predictors of caries experience among 4–5 years-old-children living in urban area of Brazil.     

Influence of the thyroid upon the glycosaminoglycans in the salivary glands in the rat

The glycosaminoglycans of the salivary glands were studied in male rats 2 months after radiothyroidectomy, and after the daily administration of 0.1 and 1.0 μg of sodium-1-triiodothyronine to radiothyroidectomized rats for 1 month. Total uronic acid concentration was determined in the salivary glands. Chromatographie separation of the uronic acid fractions was performed on cellulose microcolumns. Radiothyroidectomy increased and the administration of triiodothyronine decreased the uronic acid concentration in the submandibular glands. These changes occurred only in the hyaluronic acid and glycoprotein fractions. No changes in uronic acid concentration were detected in the retrolingual and parotid glands.     

Tooth loss and prosthodontic rehabilitation among 35- to 44-year-old Iranians

Summary  This study aimed to investigate the frequency of tooth loss and the magnitude of prosthodontic rehabilitation based on socio-demographic information among 35- to 44-year-old Iranians. Data ( n  = 8240) were collected by 33 examiners as part of a national survey using WHO criteria for sampling and clinical diagnosis. Gender, age, place of residence and level of education served as socio-demographic information. The number of teeth, functional dentition (subjects with 20 or more teeth) and prosthodontic rehabilitation were used as clinical variables. The chi-square test and logistic regression analysis were the methods of statistical evaluation. Of all subjects, 3% were edentulous. Of dentate subjects, 3% had 1–9 teeth, 21% had 10–19 teeth, 37% had 20–24 teeth and 39% had 25–28 teeth. In total, 76% of dentate subjects enjoyed a functional dentition. Among dentate subjects, 11% of the men and 16% of the women had prosthodontic rehabilitation with higher figures ( P  < 0·001) among women, older subjects and urban residents. Having a functional dentition was more likely among those with higher levels of education [odds ratios (OR) = 1·8, 95% confidence intervals (CI) = 1·6–2·1]. Women (OR = 2·4, 95% CI = 1·8–3·0) and urban residents (OR = 2·4, 95% CI = 1·8–3·3) were the most likely groups to have prosthodontic rehabilitation. Having prosthodontic rehabilitation was more likely among those lacking a functional dentition (OR = 6·0, 95% CI = 4·8–7·6). The greatest unmet treatment needs were found among those without a functional dentition. Functional dentition should be set as a primary oral health goal among working-age adults.     

Abstracts from other journals

The aim of the study was to compare 24-h urinary fluoride excretion in young children exposed to different fluoride regimes. Twenty-four-hour urine samples were collected from children aged between 1·8 and 5·2 years. Samples were collected from Cork, Ireland ( n  = 19) where the water fluoride concentration is between 0·8 and 1·0 mg/L; Knowsley, UK, where the water fluoride concentration is < 0·1 mg/L ( n  = 22); and from children in Knowsley drinking milk containing 0·5 mg fluoride in nursery school each day ( n  = 16). The volume of the samples was measured, they were analysed for fluoride concentration and the 24-h urinary fluoride excretion was calculated. It was found that the mean fluoride excretion in response to usual conditions of fluoride intake in these children was 0·21 mg (SD = 0·14) in non-fluoridated Knowsley; 0·36 mg (SD = 0·11) in fluoridated Cork and 0·30 mg (SD = 0·10) in the children drinking fluoridated school milk. The daily fluoride excretion in these children, corrected for age and fluoride ingested from toothpaste, appeared to indicate the fluoride intake in the children drinking fluoridated school milk was somewhere between those living in an optimally fluoridated area and those in a low fluoride area.     

Activity pattern of swallowing-related muscles, food properties and body position in normal humans

Summary  Activity patterns of the swallowing-related muscles were examined in normal subjects at different four body positions during swallowing of foods with different textural properties. Surface electromyograms were recorded from two muscle groups, the anterior tongue and suprahyoid muscles. The T _P technique we developed was applied to the electromyograms for quantitative analysis of the activity patterns. Three test foods were prepared by dissolving 2·0% (low), 5·7% (middle) and 9·1% (high concentration) of a thickening agent into distilled water. Each subject was delivered randomly, one of the test foods to swallow at one of the four body positions i.e. horizontal supine, 30° inclined, 60° inclined and upright. In this study, T ₅₀ values were calculated in activity data of the two muscle groups, and the T ₅₀ values were statistically examined analysis of variance with a linear model including four fixed effects of 'concentrations', 'body positions', 'subjects' and 'sessions'. Three major findings obtained were that (i) the activity pattern of the anterior tongue was altered from a decrementing discharge pattern to an incrementing discharge pattern by shifting from the upright to the horizontal supine position, (ii) the activity pattern of the suprahyoid muscles was altered from a decrementing discharge pattern to an incrementing discharge pattern by shifting from the low concentration food to the higher ones and (iii) two subgroups were detected in subjects with the significant effects of 'concentrations' and 'body positions'. These findings lead a conclusion that activity patterns of the swallowing-related muscles are affected by food properties and body positions.     

Prosthetic treatment planning on the basis of scientific evidence

Summary  The objective of this report is to summarize the results on survival and complication rates of different designs of fixed dental prostheses (FDP) published in a series of systematic reviews. Moreover, the various parameters for survival and risk assessment are to be used in attempt to perform treatment planning on the basis of scientific evidence. Three electronic searches complemented by manual searching were conducted to identify prospective and retrospective cohort studies on FDP and implant-supported single crowns (SC) with a mean follow-up time of at least 5 years. Patients had to have been examined clinically at the follow-up visit. Failure and complication rates were analyzed using random-effects Poisson regression models to obtain summary estimates of 5- and 10-year survival proportions. Meta-analysis of the studies included indicated an estimated 5-year survival of conventional tooth-supported FDP of 93·8%, cantilever FDP of 91·4%, solely implant-supported FDP of 95·2%, combined tooth-implant-supported FDP of 95·5% and implant-supported SC of 94·5% as well as resin-bonded bridges 87·7%. Moreover, after 10 years of function the estimated survival decreased to 89·2% for conventional FDP, to 80·3% for cantilever FDP, to 86·7% for implant-supported FDP, to 77·8% for combined tooth-implant-supported FDP, to 89·4% for implant-supported SC and to 65% for resin-bonded bridges. When planning prosthetic rehabilitations, conventional end-abutment tooth-supported FDP, solely implant-supported FDP or implant-supported SC should be the first treatment option. Only as a second option, because of reasons such as financial aspects patient-centered preferences or anatomical structures cantilever tooth-supported FDP, combined tooth-implant-supported FDP or resin-bonded bridges should be chosen.     

Patterns of missing occlusal units and oral health-related quality of life in SDA patients

Summary  The aim of this study was to explore the relationship between patterns of missing occlusal units (OUs) and oral health-related quality of life (OHRQoL) in subjects with the shortened dental arches (SDAs). Subjects with SDAs were recruited consecutively for 1 month from six university-based prosthodontic clinics. In total, 115 SDA subjects participated (mean age, 58·5 ± 10·0 years; 71% female). The location and number of missing teeth were examined and the number of missing OUs was calculated. To evaluate OHRQoL, the Japanese version of the Oral Health Impact Profile (OHIP-J) was administered and the summary score of OHIP-J was calculated. The SDA subjects were categorized depending upon the anterior-posterior lengths of the missing or remaining OUs. Regression analyses were performed to investigate the OHIP-J differences between groups of subjects with various anterior–posterior SDA lengths. The analyses revealed that subjects who only lost the second molar contact exhibited significantly better OHRQoL than those who lost more teeth [coefficient: 11·1, 95% confidence interval (CI): 2·8–19·2, P  = 0·02]. Furthermore a statistically significant group difference was observed between the groups with and without the first molar occlusal contact (coefficient: 12·8, 95% CI: 1·4 to 24·1, P  = 0·03). In conclusion, although our results are of exploratory nature and need validation, patterns of missing OUs are likely to be related to the OHRQoL impairment in SDA subjects with the presence of first molar contact having a particularly important role.     

Automated analysis for portable EMG recording of nocturnal masseter activity in bruxers

Facial pain of patients with craniomandibular disorders might be caused by muscle overload. In a former study ( Gallo et al ., 1999 ) we collected data on masseter EMG of healthy subjects during sleep by means of portable recorders (integration time of 500 ms). The automated analysis of the tracings yielded the normal range of activity in the natural environment. For this study, we focused on the analysis of the distribution of masseter activity in bruxers by means of the same automated system used for asymptomatic subjects.
For this purpose, data from single masseter channels of polysomnographic recordings of 10 bruxers and 10 controls were reformatted as if they had been recorded by means of the portable devices. The signals were analysed for number, amplitude and duration of contraction episodes (signal portions above a threshold which could contain subthreshold portions shorter than the standby time of 5 s). The signal amplitude was expressed in percentage of the amplitude at maximum voluntary contraction (%MVC).
In the bruxers, 166·8 ± 48·5 contraction episodes per night, i.e. 20·4 ± 5·7 h ⁻¹ , with a net duration of 8·4 ± 2·4 s and an integral of the amplitude over time of 191·6 ± 74·0 %MVCs were found (controls: 96·5 ± 39, 12·9 ± 3·5, 4·7 ± 1·2 s and 99·1 ± 28·0 %MVCs, respectively) . For these parameters there was a statistically significant difference between the two groups ( t -test, P  < 0·01). The distribution of all contraction episodes of all bruxers according to net duration and mean amplitude was shifted towards shorter episodes with a massive presence of episodes between 60 and 70% MVC, much higher than in controls.     

Effects of buccal bi-cortical anchorages on primary stability of dental implants: a numerical approach of natural frequency analysis

Summary  The purpose of this study was to investigate influences of buccal bi-cortical anchorages on natural frequency (NF) values of dental implants in different diameters utilizing the three-dimensional finite element method. Three degrees of buccal bi-cortical engagements were generated in D2 and D3 bone quality models, which were 0-mm engagement (i.e. implants just had contact with the buccal cortex), 0·5-mm (i.e. implants were penetrated into the buccal cortex by 0·5 mm) and 1·0-mm engagement, while only 0- and 0·5-mm engagement were simulated in D4 bone models. The uni-cortical engagement was set as the control. By the modal analysis, NF values of bending and axial vibration mode were computed as a function of different bi-cortical engagements. The results showed that buccal bi-cortical anchorages significantly enhanced bending and axial NF values. The increasing rates resulting from 0·5-mm engagement ranged from 10·5 to 42·3%, with a mean of 24·3%. From 0- to 0·5-mm engagement, the NF values maintained an increasing trend, and from 0·5- to 1·0-mm engagement, the values levelled off or even decreased. In 0·5- and 1·0-mm engagement models, increasing implant diameter resulted in small increases of NF values. In conclusion, buccal bi-cortical anchorages could significantly increase both bending and axial NF values of dental implants, but extra-buccal cortical bone engagement could not produce considerable incremental increases of NF values as anticipated. Increasing implant diameter could result in limited increases of NF values in case of implants being bi-cortically anchored.     

Caries and dental fluorosis in a 0·25 and a 2·5 ppm fluoride area in the Sudan

The purpose of this study was to assess the caries prevalence of children living in areas with either 0·25 or 2·5 ppm fluoride in the drinking water, and to relate caries experience to the severity of dental fluorosis. The children, aged 6–16 years (mean 11·3 years), were lifelong residents of their rural villages. The severity of dental fluorosis in the maxillary central incisors, assessed by Deans index, was 1·4 ± 0·9 ( n  = 59) and 2·3 ± 0·9 ( n  = 65) in the 0·25 and 2·5 ppm areas, respectively. There was no significant difference in DMFT between children from the two areas (2·6 ± 2·3 n  = 59 versus 2·1 ± 2·3, n  = 65). In the low-fluoride area 75% of the children had decayed permanent teeth compared to 66% in the high-fluoride area. In the primary teeth, however, both the caries prevalence and the dmft were significantly lower in the 2·5 ppm area than in the low-fluoride area. Stepwise, multiple, linear regression analyses, including all children, showed a significant effect of age on DMFT (30% of the variance explained), but no explanatory effect of fluoride in drinking water, severity of dental fluorosis, or gender. Regression analyses based on children in the 2·5 ppm area alone, showed significantly higher DMFT by increased severity of dental fluorosis. In children with a mixed dentition ( n  = 66), there was no association between caries in the primary and permanent teeth.     

Occlusal relationships and spacing or crowding of teeth in the dentitions of 3–4-year-old Nigerian children

A study of 525 3–4-year-old children in nursery schools and day-care centres was carried out to assess occlusal relationships and the presence of spacing or crowding of teeth. No significant differences in occlusal relationships were found between boys and girls ( P  > 0·05). Bilateral straight terminal planes of molars and class 1 canine relationship were the most prevalent features (74·5% and 73·3% respectively). Most of the children had 'normal' vertical and transverse occlusal relationships. The most common sites of spacing were mesial to maxillary canines and distal to mandibular canines. 32% of the children were found to have generalized anterior segment spacing, 4% showed exclusively anthropoid spaces, and 18% had either contact between all the teeth or crowding in the anterior region.