[Caries risk assessment - are saliva tests as well as microbiological and clinical test procedures worthwhile?]. / Kariesrisikoerkennung - Helfen Speicheltests, mikrobiologische und klinische Testverfahren weiter?

The recent representative survey has proven once more that people in Germany are affected by caries to a very different extent. Since caries can be prevented by risk-adjusted preventive programs, it would be helpful to have a possibility to determine the individual caries risk before cavities occur. Determination of a relative risk, risk screening and risk diagnosis are different levels of caries risk assessment. The present article provides information about which caries risk assessment options are available for different populations. A relative risk can be determined by the detection of Mutants Streptococci in caries-free 2-5-year-old children. With Dentoprog, a valid instrument for caries risk screening is available for 6-12-year-old school children. With respect to all other patients, a quantitative risk diagnosis can be roughly performed using the Cariogram which is based on the assessment of multiple risk parameters. The conclusion is that several options for caries risk assessment for different age groups are available. Nevertheless, there is no solution to how often a patient should appear for prevention in a dental office nor which preventive measures have to be taken to keep him/her healthy. Therefore it seems reasonable to roughly determine the recall frequency on the basis of the respective risk assessment and to adjust this frequency over time after the evaluation of disease progression.

A new method to assess the results of instrumentation techniques in the root canal.

In the present study, the shape of the root canal was assessed with pre- and postinstrumentation silicone impressions. Curved root canals of 30 extracted molars were instrumented with the Canal Leader (CL), the ProFile System (PF), and hand instrumentation (HI). Photographs from each impression were digitized, and the enlargement of the canals was computed by substracting the preinstrumentation from the postinstrumentation images. Technical errors of preparation were also recorded. There was no significant difference in total dentin removal between the systems. However, CL removed significantly more dentin from the convex side of the root canal than PF. Instrument separation occurred in five cases, only with PF. Roughness of canal walls was recorded significantly more often with the use of CL than with PF or HI. CL also produced a significantly higher incidence of elbow formation, compared with PF or HI. With this method of assessment, it was possible to record details and differences between the tested instrumentation techniques.

Pulp capping of carious exposures: treatment outcome after 5 and 10 years: a retrospective study.

One hundred twenty-three pulp cappings had been performed by students in 1984 to 1987 (= 10-yr group) or in 1990 to 1992 (= 5-yr group) and were followed up in 1997. Teeth were checked for sensitivity (CO2/electrical pulp testing), percussion, and palpation; radiographs were taken to assess periapical status. In addition several other factors were determined that might have an influence on the success or failure rates, such as base material, type of restoration, site of exposure, etc. Results showed 44.5% failures (18.5% questionable and 37% successful cases) in the 5-yr group and 79.7% failing, 7.3% questionable, and 13% successful cases in the 10-yr group. As a factor of influence, the placement of a definitive restoration within the first 2 days after pulp exposure was found to contribute significantly to the survival rate of these teeth.

Dye penetration in root canals filled with AH26 in different consistencies.

It is recommended that the powder to liquid ratio of AH26 be very high and that the mixture be warmed to decrease viscosity before insertion into the root canal. In this study, the effectiveness of the powder to liquid ratio and temperature were assessed using 60 root canals of maxillary central incisors randomly divided into four groups after their cleaning and shaping. The teeth were obturated by either lateral condensation or the single-cone technique using AH26 warmed or at room temperature. After exposure to basic fuchsin, the teeth were embedded and cross-sectioned using a diamond saw. The dye penetration was measured microscopically and reported as a percentage of the total circumference of the filling of each slice using a goniometric eye-piece. After statistical analysis, it was concluded that AH26 in combination with lateral condensation leads to less leakage when used at room temperature.

Long-Term bacterial leakage along obturated roots restored with temporary and adhesive fillings.

The aim of this study was to examine whether obturated roots combined with several adhesive and temporary filling materials can be bypassed by bacteria. Standardized cavities were coronally prepared into 130 straight roots mimicking clinical access cavities. After obturation the roots were assigned to six test and three control groups and coronally sealed with either Clearfil, CoreRestore, IRM, Ketac Fil, or a combination of IRM/wax or Ketac Fil/wax. The roots were then fixed between a top and a bottom chamber each. The top chamber contained soy broth with 108 Staphylococcus epidermidis colony-forming units/ml, and the bottom chamber contained sterile soy broth. For 1 yr the mounts were checked on a regular basis for turbidity in their bottom chambers indicating bacterial growth. After 1 yr only three samples from the CoreRestore group and two samples from the Clearfil group resisted leakage. At termination there was no significant difference in number of leaking samples among the groups. At the beginning of the experiment IRM performed worst. Between months 5 and 10 Clearfil showed the least leaking samples; for some months this was statistically significant compared with IRM or Ketac Fil.

Leakage in roots coronally sealed with different temporary fillings.

This study was aimed at determining the ability of different coronal temporary fillings to prevent corono-apical penetration of bacteria. A total of 103 human teeth, including three controls, were instrumented, obturated with gutta-percha, coronally sealed with either Cavit, Intermediate Restorative Material (IRM), glass-ionomer cement, Cavit/glass-ionomer cement, or IRM/glass-ionomer cement, respectively. Each root was fixed with wax between two chambers: the coronal chamber harboring soy broth with 10(8) colony-forming units of Streptococcus mutans/ml, the apical chamber containing sterile soy broth. The latter was checked daily for turbidity, indicating corono-apical penetration of bacteria. The Cavit group, the IRM group, and the Cavit/glass-ionomer cement group showed significantly more leakage than the glass-ionomer cement group of the IRM/glass-ionomer cement group. If a sample leaked, all except one (IRM/glass-ionomer cement) leaked before day 12. This in vitro study seems to indicate that only glass-ionomer cement and IRM combined with glass-ionomer cement may prevent bacterial penetration to the periapex of root-filled teeth over a 1-month period.

A new fluoride-releasing rubber cup for professional oral hygiene.

Rubber cups in combination with prophylaxis pastes are commonly used for supragingival professional tooth cleaning. This procedure requires frequent interruption in order to collect fresh paste. Moreover, the paste-saliva slurry blurs the visibility, which implies intermittent rinsing to look for residual discolorations. Hawe Neos Dental (Bioggio, Switzerland) has developed a new prophylaxis cup aimed at cleaning and smoothing the tooth surfaces, while simultaneously fluoridating the enamel without a prophylaxis paste. This new prophylaxis cup was tested with respect to cleaning efficiency, resulting surface roughness, abrasivity, and the promotion of fluoride uptake into enamel. After 15 seconds of use, the new cup showed a cleaning efficiency which was 20 to 30% higher than that of a conventional rubber cup (p < 0.01) used with the prophylaxis pastes Nupro coarse or Hawe cleanic (78% vs. 57 and 49%). The fluoride cup had a smoothing effect on the enamel surface comparable to that effected by the two prophylaxis pastes. The abrasivity on enamel was lowest with the new cup. On dentin, abrasivity was comparable to Nupro coarse, but higher than with Hawe cleanic. The fluoride cup also produced a higher amount of KOH-soluble fluoride on the enamel surface when compared to Hawe cleanic. With respect to the structurally bound fluoride, no difference was found. The newly developed fluoride releasing Hawe Neos cup represents an effective alternative to conventional procedures for supragingival professional tooth cleaning on enamel.

Fluoride release from a toothbrush.

The purpose of the present study was to evaluate the fluoride concentration in unstimulated saliva after using a toothbrush with 9,048 ppm fluoride as sodium fluoride incorporated in the bristles. A toothpaste with 1,500 ppm fluoride served as the positive control. Twelve volunteers took part in the single-blind crossover study. In a pre-test phase of 14 days, the subjects refrained from eating fluoride-rich foods and did not use any fluoride-containing products for oral hygiene measures. This was followed by a test period of four weeks. At day one and after 14 and 28 days, unstimulated saliva was collected and analyzed for its fluoride content. Saliva was collected immediately after toothbrushing and after 15, 30, 60, 90, 120 150, and 180 minutes. On day one, the fluoride toothbrush released significant amounts of fluoride immediately after the brushing, and after 15 and 30 minutes (p < 0.01). After 14 days of use, this could be found immediately after brushing and after 15 minutes (p < 0.01 or p < 0.05, respectively). After 28 days, a significant fluoride release was only found immediately after brushing (p < 0.05). On all days, compared to the positive control, the fluoride release from the fluoride toothbrush was generally lower immediately after brushing and after 15 minutes (p < 0.001, p < 0.01 or p < 0.05, respectively). It may be concluded that a toothbrush with incorporated sodium fluoride could act as a fluoride-releasing. device.

A new approach to define defect extensions of endodontically treated teeth: inter- and intra-examiner reliability.

For endodontically treated teeth, there are no standardized measures available to define the extent of loss in tooth substance prior to final restoration. In this study, defect size was classified and the applicability of the classification was tested related to the inter- and intra-examiner reliability. For classification, three parameters were investigated: (i) remaining tooth substance in the vertical dimension (level A-D, aspect I), (ii) remaining tooth substance as regarded horizontally (mm; bucco-lingual and mesio-distal, aspect II), and (iii) size of the orifice (mm; aspect III). Four non-calibrated or (pre-trained) examiners were asked to gauge and classify 20 casts of clinically broken down teeth. The measurements were repeated twice every alternative week giving three separate readings. Inter-examiner reliability was determined at weeks 1, 3 and 5. The intra-examiner reliability was compared between readings 1 and 2, 1 and 3, and 2 and 3. As statistical tests, intra-class correlation (ICC) and Cohen's kappa (weighted) were used at a significance level of P < 0.05. Inter- and intra-examiner reliability for ordinal data (aspect I) revealed, with one exception, 'moderate' to 'very good' evaluations. Inter- and intra-examiner reliability (ICC) of metric data of aspect II and III was primarily 'excellent'. It may be concluded that the newly developed classification could be applied as an appropriate and reproducible method to define defect extension in endodontically treated teeth.

Evaluation of dentin abrasion during professional tooth cleaning in an in vitro model.

OBJECTIVES: Professional tooth cleaning (PTC) may lead to loss of exposed dentin. The aim of the present study was to determine the absolute loss of dentin during PTC using various product combinations with an in vitro model. MATERIAL AND METHODS: Dentin specimens (72) were randomly assigned to nine groups. In four groups each, prophy brushes and prophy cups were used in combination with four different abrasives (calcium pyrophosphate, pumice, Hawe cleanic, Nupro coarse). In the ninth group, a rubber cup with embedded fluoride and abrasives was used (pasteless prophy cup). The treatment time was 37 s. Surface loss was determined by profilometry. RESULTS: The surface loss in the nine groups was as following: (1) brush/calcium pyrophosphate: 6.18 microm (a); (2) brush/pumice: 5.51 microm; (3) brush/Nupro coarse: 10.10 microm (b); (4) brush/Hawe cleanic: 1.88 (a, b); (5) prophy cup/calcium pyrophosphate 2.07 (c); (6) prophy cup/pumice: 6.07 microm; (7) prophy cup/Nupro coarse: 5.93 microm (c); (8) prophy cup/Hawe cleanic: 4.93 microm (c); (9) pasteless prophy cup: 11.86 microm (c). Groups with the same letter in parentheses are statistically significant different at p<0.05. In a pooled analysis, no statistically significant difference between brushes and prophy cups was found. CONCLUSION: In the present study, the surface loss of about eight PTC procedures was simulated. Hence, the dentin loss ranged between 0.24 and 1.48 microm per PTC. Therefore, PTC does not seem to be a main factor in dentin loss.

Can we fulfil even the basics of endodontic therapy?

Micro-organisms and lipopolysaccharides (LPS) are involved in inducing periapical inflammation. Therefore, it is important to eliminate them from the complex root canal system and seal the endodontic space as accurately as possible. This is possible with a combination of the following: instrumentation of the canal, eventually with new, motor driven instruments, abundant rinsing with NaOCl, dressing preferably with Ca(OH)2, sealing the root canal and incorporating the permanent restoration within three months after root canal filling to avoid reinfection.

[Effective of preventive programs on oral hygiene of adults and school children]. / Einfluss von Prophylaxeprogrammen auf die Mundhygiene von Erwachsenen und Schulkindern.

The improvement of dental hygiene is considered to be one of the most important measures in dental health education. Hence, it was the aim of the present study to investigate the influence of two similar preventive programmes on oral hygiene performed in adults and schoolchildren. In the adult study, the oral hygiene indices PI (Quigley-Hein) and API (Lange) could be significantly improved after six months by an individualized preventive programme performed every three months. Besides repeated instructions and motivations in oral hygiene, the programme included professional toothcleaning. In contrast, nine-year old schoolchildren showed no improvement in the oral hygiene indices PI and PBI (Mühlemann and Son) after applying a similar programme over three years. For the PI, even a deterioration from 1.86 at the beginning of the study to 2.65 at the final examination was seen. Other authors were more successful by applying a programme without professional toothcleaning but with inclusion of the parents. It is therefore concluded that children should be educated to oral self-care by including their parents and by taking their status of psychological development into account.

Bacterial leakage versus dye leakage in obturated root canals.

AIM: The aim of this study was to compare in vitro bacterial and dye leakage tests, commonly used to determine the seal of root canal fillings. METHODOLOGY: Ninety-six single-rooted teeth had their crowns removed at the cemento-enamel junction and their roots instrumented to ISO size 60 within 1 mm of the apex. Three groups of 30 roots were obturated by lateral condensation using gutta-percha and one or other of the sealers. AH26, Ketac Endo, or Roth's 801 sealer. Three roots were used as negative controls and three roots as positive controls. The roots were then exposed at their coronal end first for 38 days to soy broth containing Staphylococcus epidermidis and thereafter for 48 h to basic fuchsin. Bacterial leakage was recorded when the challenging organism could be recovered from the apical end. Dye leakage was checked by microscopy of transverse sections of the apical tip at the end of the experiment. RESULTS: For the bacterial experiment, there was no significant difference amongst the three sealer groups. The dye experiment showed significantly greater leakage in the AH26 compared to the Ketac Endo group. No correlation between the results of the two tests could be seen. CONCLUSIONS: The results of this study suggest that the molecular size of the penetrating agent may not be the relevant parameter when attempting to determine an appropriate test for the sealability of root canal fillings.

[Dental group prophylaxis - for children only?]. / Zahnmedizinische Gruppenprophylaxe - nur für Kinder?

In Germany, caries in 12-year olds have declined by 70 % in the last decade. This was the result of a variety of preventive measures such as salt fluoridation, group related prevention in schools and kindergartens, and individualized preventive measures offered in dental offices. On a national scale, salt fluoridation seems to be the measure with the highest efficacy and efficiency. Firstly, it has the potential to reach the entire population, and secondly it is highly cost-effective. The cost-benefit ratio for salt fluoridation ranges from 25 to 80, e. g. for one Euro spent on prevention, 25 to 80 Euro can be saved in therapy. However, salt fluoridation alone cannot stop caries, and it is not at all effective in preventing gingivitis and periodontitis. Therefore, additional measures have to be taken. The cost-benefit ratio for group-related prevention ranges from 2.4 to 19.5 and for individualized prevention from 0.7 to 2.1. Besides the better cost-effectiveness, group-related prevention has the advantage of advanced target group attainment. For example, it is easy to reach children in schools whereas it is difficult to review them in a dental office. Therefore, group related-prevention should have priority. This should not be restricted to children and adolescents, seniors can also be attended in groups. In Germany, about 950,000 people live in old people's homes, and additionally about 570,000 people in nursing homes. This population often suffers from severe oral health problems such as caries, periodontitis, and diseases involving the mucosa. Taking into account that the number of elderly institutionalized people is increasing in Germany, the establishment of group-related prevention for this part of the population seems to be an important goal in health policy.

Bacterial leakage in obturated root canals following the use of different intracanal medicaments.

The aim of this study was to examine whether intracanal medication prior to root canal obturation has an inhibitory effect on corono-apical penetration of bacteria. 93 single rooted teeth were instrumented and sterilized with ethylene oxide. They were assigned to three control groups and four test groups with n = 20 each. For one week, they were dressed with different medicaments: The first group with a 5% chlorhexidine gel, the second with Ledermix, the third with a fresh mix of calcium hydroxide and water and the fourth without any medication. After obturation (lateral condensation, AH26) the roots were fixed between a top and a bottom chamber. The top chamber contained 3 mL trypticase soy broth with 10(8) Staphylococcus epidermidis CFU's/mL, whereas the bottom chamber contained sterile trypticase soy broth. For one year, the mounts were incubated at 37 degrees C. They were checked on a regular basis for turbidity in their bottom chambers indicating bacterial growth. None of the test samples leaked for three months. After one year, the calcium hydroxide group had only 6 leaking samples whereas the chlorhexidine group had 14, the Ledermix group 15, and the unmedicated group had 13 leaking samples. It may be concluded that under the conditions of this study, calcium hydroxide was the medicament of choice to avoid bacterial penetration of the root canal. Ledermix did not perform better than no premedication. Chlorhexidine was superior to Ledermix in the second third of the observation period.

Kinetic cavity preparation--hit or flop?

The preparation of dental hard tissues is carried out primarily with rotating instruments and is known to have some shortcomings. Kinetic cavity preparation (KCP) seems to be a desirable alternative. Nevertheless, scientific investigations and clinical experiences revealed numerous disadvantages which have led to a clear limitation of its use. For example, KCP can not replace the normal conditioning of enamel by acid etching. The hopes connected with the re-introduction of this technology for conservative dentistry have not been fulfilled.

TNF-alpha release in monocytes after exposure to calcium hydroxide treated Escherichia coli LPS.

Lipopolysaccharide (LPS), a cell wall component of Gram negative anaerobic bacteria, has been implicated in the pathogenesis of periapical disease resulting from infected root canals. Calcium hydroxide [Ca(OH)2] has been shown to be an effective medicament in such infections, reducing the microbial titre within the canal. It has been proposed that the therapeutic effect of Ca(OH)2 may also be the result of direct inactivation of LPS. The aim of this study was to investigate whether the toxic potential of an Escherichia coli LPS could be reduced or eliminated by Ca(OH)2. Four concentrations of E. coli LPS ranging from 1-1000 ng/ml sterile water were incubated in duplicate either with 25 mg Ca(OH)2 or sterile water alone. Controls consisted of Ca(OH)2 without LPS or sterile water only. Monocytes were collected from peripheral blood by centrifuging through a gradient and plated to a specific density. Adherent monocytes were incubated for 4 days at 37 degrees C with 5% CO2 in M199 medium with 10% autologous serum. The different LPS solutions were added to the wells on day 5. After 4 h the supernatants were collected and quantitatively assayed for TNF-alpha using a commercial ELISA kit. Statistical analysis was performed with ANOVA. Results indicated that Ca(OH)2 is able to eliminate the ability of an E. coli LPS to stimulate TNF-alpha production in peripheral blood monocytes (P < 0.0001).

Transponder-induced sarcoma in the heterozygous p53+/- mouse.

Heterozygous p53+/- transgenic mice are being studied for utility as a short-term alternative model to the 2-yr rodent carcinogenicity bioassay. During a 26-wk study to assess the potential carcinogenicity of oxymetholone using p-cresidine as a positive control, glass/polypropylene microchips (radio transponder identification devices) were subcutaneously implanted into male and female p53+/- mice. During week 15, the first palpable mass was clinically observed at an implant site. This rapidly growing mass virtually quadrupled in size by week 25. Microscopic examination of all implant sites revealed that 18 of 177 animals had a subcutaneous histologically malignant sarcoma. The neoplasms were characterized as undifferentiated sarcomas unrelated to drug treatment, as indicated by the relatively even distribution among dose groups, including controls. An unusual preneoplastic mesenchymal change characterized by the term "mesenchymal dysplasia" was present in most groups and was considered to be a prodromal change to sarcoma development. The tumors were observed to arise from dysplastic mesenchymal tissue that developed within the tissue capsule surrounding the transponder. The preneoplastic changes, including mesenchymal dysplasia, appeared to arise at the transponder's plastic anchoring barb and then progressed as a neoplasm to eventually surround the entire microchip. Capsule membrane endothelialization, inflammation, mesenchymal basophilia and dysplasia, and sarcoma were considered unequivocal preneoplastic/neoplastic responses to the transponder and were not related to treatment with either oxymetholone or p-cresidine.