Sustained release of calcium hydroxide from poly(DL-lactide-co-glycolide) acid microspheres for apexification.

Calcium hydroxide (CH) loaded poly(DL-lactide-co-glycolide) acid (PLGA) microspheres (MS) might be used for apexification requiring a sustained release of Ca(2+). The aim of this study was to formulate and characterize CH-PLGA-MS. The CH-loaded MS were prepared by either oil-in-water (O/W) or water-in-oil/in-water (W/O/W) emulsion solvent evaporation technique. MS produced by the O/W technique exhibited a larger diameter (18.63 ± 7.23 µm) than the MS produced by the W/O/W technique (15.25 ± 7.37 µm) (Mann-Whitney U test P < 0.001). The CH encapsulation efficiency (E e) and Ca(2+) release were calculated from data obtained by absorption techniques. Ca(2+) release profile was evaluated for 30 days. To know the E e, the CH-loaded MS were dissolved in 1 M NaOH to release all its content and a Ca(2+) colorimetric marker was added to this solution. The reagent marked the Ca(2+) in blue color, which was then measured by a UV-Vis system (650 nm). The percentage of E e was calculated on the basis of the theoretical loading. The E e of the O/W-produced MS was higher (24 %) than the corresponding percentage of the W/O/W-produced MS (11 %). O/W- and W/O/W-produced MS released slower and lower Ca(2+) than a control CH paste with polyethylene glycol 400 (Kruskal-Wallis test). O/W-produced MS released higher Ca(2+) than W/O/W-produced MS (statistically significant differences; P < 0.05). In conclusion, the CH-PLGA-MS were successfully formulated; the technique of formulation influenced the size, encapsulation efficiency and release profile. The MS were better sustained release system than the CH paste.

Micro-CT determination of the porosity of two tricalcium silicate sealers applied using three obturation techniques.

PURPOSE: Using X-ray micro-computed tomography (micro-CT), the aim of this study was to measure the porosity of two tricalcium silicate sealers (EndoSequence BC and NeoSealer Flo) applied using three obturation techniques (single-cone, warm-vertical, and cold-lateral) to six single-rooted human teeth. METHODS: Six extracted, single-rooted human teeth were shaped with ProTaper Next rotary files and obturated with EndoSequence BC or NeoSealer Flo sealers and gutta-percha (GP) using one of the three techniques above. Micro-CT was used to map the full length of the canals. Deep learning cross-sectional segmentation was used to analyze image slices of the apical (0-2 mm) and coronal (14-16 mm from the apex) regions (n = 230-261 per tooth) for the areas of GP and sealer, as well as porosity. Median (%) with interquartile range of porosity were calculated , and the results were statistically analyzed with the Kruskal-Wallis test. RESULTS: In the apical region, EndoSequence BC had significantly fewer pores than NeoSealer Flo with the single-cone obturation (% median-interquartile range, IQR: 0.00-1.62) and warm-vertical condensation (5.57-10.32) techniques, whereas in the coronal region, NeoSealer Flo had significantly fewer pores than EndoSequence BC with these two techniques (0.39-5.02) and (0.10-0.19), respectively. There was no significant difference in porosity between the two sealers for the cold-lateral condensation technique in both the apical and coronal regions. CONCLUSION: For optimal obturation, the choice of technique and sealer is critical.

Candida dubliniensis in Japanese Oral Microbiota: A Cross-Sectional Study of Six Geographic Regions in Japan.

INTRODUCTION: Candida dubliniensis was reclassified from the C. albicans genotype D, and reports show its frequent detection in HIV-positive individuals and easy acquisition of antifungal drug resistance. However, the oral carriage rate in healthy people and contribution to candidiasis in Japan is unclear. METHODS: We conducted a cross-sectional survey of the C. dubliniensis carriage rate, performed genotyping and tested antifungal drug susceptibility and protease productivity. Specimens from 2432 Japanese subjects in six regions (1902 healthy individuals, 423 with candidiasis individuals, 107 HIV-positive individuals) were cultured using CHROMagarTMCandida, and the species was confirmed via 25S rDNA amplification and ITS sequences analyzed for genotyping. RESULTS: The C. dubliniensis carriage rate in healthy Japanese was low in the central mainland (0-15%) but high in the most northerly and southerly areas (30-40%). The distribution of these frequencies did not differ depending on age or disease (HIV-infection, candidiasis). Genotype I, previously identified in other countries, was most frequent in Japan, but novel genotypes were also observed. Six antifungal drugs showed higher susceptibility against C. albicans, but protease productivity was low. CONCLUSIONS: Oral C. dubliniensis has low pathogenicity with distribution properties attributed to geography and not dependent on age or disease status.

Successful Non-Surgical Root Canal Treatment on Auto-Transplanted Maxillary Premolar with Apical Periodontitis.

Auto-transplantation is a procedure that replaces traumatized or congenitally missing teeth. While most auto-transplanted teeth are successfully integrated into recipient sites, the donor tooth may develop apical periodontitis, causing early failure. In the present case report, the periodontic resident performed the procedure on a 15-year-old male by selecting donor teeth #4 and #13 and transplanting them at recipient sites #29 and #20, respectively. After 6 weeks, the patient was referred to the endodontic resident for evaluation of tooth #20 due to symptom development. While one auto-transplanted tooth (donor tooth #4, recipient site #29) was successfully integrated, the other (donor tooth #13, recipient site #20) was unsuccessful: the patient was diagnosed with pulp necrosis and a chronic apical abscess. Because of the patient's age, collaboration among periodontic, endodontic, and orthodontic residents/specialists informed the clinical decision to pursue non-surgical root canal treatment (NSRCT) rather than extraction. The canal was cleaned and shaped to a size #80 using copious irrigation of 2.5% sodium hypochlorite (NaOCl), followed by 17% ethylenediaminetetraacetic acid (EDTA) via the EndoVac Negative Pressure Irrigation system. The tooth was dried with paper points, and then calcium hydroxide was mixed with 2.5% NaOCl and placed with an amalgam carrier 2 mm from the radiographic apex. The tooth was next temporized with Teflon tape and Fuji TRIAGE. Four weeks later, after confirming the patient was asymptomatic and tooth mobility had decreased, the canal was obturated using EndoSequence Bioceramic Root Repair Material Fast Set Putty in 2 mm incremental layers to achieve a three-dimensional fill and create an apical plug to prevent gutta-percha extrusion, then backfilled in incremental layers of gutta-percha to the cementoenamel junction (CEJ). At the 8-month follow-up, the patient was asymptomatic, and the periodontal ligament (PDL) had no signs of periapical pathology. When teeth undergoing auto-transplantation procedures develop apical periodontitis, NSRCT can be implemented.

Coronal and apical leakage among five endodontic sealers.

PURPOSE: The aim of this study was to use dye penetration to measure apical and coronal leakage simultaneously in single-canal teeth that had been treated endodontically using a single-cone obturation technique. METHODS: One hundred single-canal, extracted human teeth were cleaned and shaped with ProTaper NEXT rotary files to size-X5 (50/.06), then randomly assigned to five sealer groups for single-cone gutta-percha obturation. The teeth were soaked in 0.6% rhodamine B at 37°C for seven days, then the roots were ground mesiodistally and the maximum apical and coronal dye penetration was measured. Differences in leakage among the sealer groups were examined using the Kruskal-Wallis test. Pairwise comparisons were made using the Mann-Whitney test with Bonferroni correction. RESULTS: The mean values (mm) of dye penetration for AH Plus, Pulp Canal Sealer, NeoSEALER Flo, EndoSequence BC, and Super-Bond RC Sealer were 0.200, 0.300, 0.675, 0.850, and 0.900 apically, whereas 1.675, 2.075, 4.800, 6.500, and 4.125 coronally. Pairwise comparisons showed significant apical differences between AH Plus/Super-Bond RC Sealer (P = 0.047) and significant coronal differences between AH Plus/NeoSEALER Flo (P = 0.001), AH Plus/EndoSequence BC (P < 0.01), AH Plus/Super-Bond RC Sealer (P < 0.01), Pulp Canal Sealer/NeoSEALER Flo (P = 0.010), Pulp Canal Sealer/EndoSequence BC (P < 0.01), and Pulp Canal Sealer/Super-Bond RC Sealer (P < 0.01). CONCLUSION: Coronal leakage was worse than apical leakage for all sealers. AH Plus exhibited the least leakage apically and coronally; Super-Bond RC Sealer showed the most leakage apically, and EndoSequence BC showed the most leakage coronally.

Use of micro-CT to examine effects of heat on coronal obturation.

PURPOSE: The aim of this study was to categorize the effects of heat on coronal obturation with gutta-percha and sealer using X-ray micro-computed tomography (micro-CT). METHODS: Ten single-rooted, extracted human teeth were shaped using ProTaper NEXT files to size X5 (#50/Taper 6%) with 2.5% NaOCl irrigation. A single ProTaper NEXT X5 gutta-percha point was then inserted with epoxy resin (AH Plus) or tricalcium silicate (EndoSequence BC) sealer (n = 5/group), and cut at the cemento-enamel junction. The teeth were scanned using micro-CT (SkyScan1272) to obtain 11 sagittal 2-D images. Three calibrated raters categorized the coronal 0.5 mm of the images into four categories: "swirled sealer and/or gutta-percha without voids" (I), "uniform voids and sealer/gutta-percha" (II), "non-uniform voids and sealer/gutta-percha" (III), and "swirled sealer and/or gutta-percha with voids" (IV). Intra-rater and inter-rater reliability were then calculated. Chi-square tests were conducted to determine the significance of differences in each category between sealers. RESULTS: The intra-class correlation coefficient was 0.55 (same rater/two different times) and Fleiss' kappa (different raters/same image) was 0.34. Categories I, II, III, and IV accounted for 16.4%, 4.2%, 30.3%, and 49.1% for AH Plus, and 6.7%, 4.2%, 27.3%, and 61.8% for EndoSequence BC, respectively. CONCLUSION: Category IV was most common and Category II the least common. Significant differences were evident between sealers for Category I (P < 0.01).

Effects of heat on seven endodontic sealers.

PURPOSE: To examine the microscopic surface features, chemical composition, and thermodynamic profile of seven endodontic sealers (AH Plus, Adseal, MTA-Fillapex, RoekoSeal, GuttaFlow 2, GuttaFlow BioSeal, and EndoRez) exposed to high-temperature changes using an endodontic obturation device. METHODS: The thermal properties were examined using scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Then, six disc-shaped specimens of each sealer were prepared and divided into two groups - a room temperature group and a heat exposure group - for analysis of surface and chemical changes using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). RESULTS: DSC analysis showed that AH Plus had the highest exothermal signal (122.9°C), while TGA analysis showed that MTA-Fillapex was most affected by increased temperature (32.4% mass loss at 230ºC). SEM analysis showed that while AH Plus and GuttaFlow BioSeal maintained their surface integrity after heat exposure, the EDS profiles demonstrated changes in the chemical composition of the sealers after heat exposure for 5 s. High-temperature exposure had a negative impact on the properties of five of the sealers (Adseal, MTA-Fillapex, RoekoSeal, GuttaFlow 2, and EndoRez). CONCLUSION: AH Plus and GuttaFlow BioSeal showed minimal changes upon high-temperature exposure, suggesting their suitability for thermal endodontic obturation techniques.

Ion Release From Prototype Surface Pre-Reacted Glass Ionomer (S-PRG) Sealer and EndoSequence BC Sealer.

OBJECTIVE: Bioactive ions, when incorporated in an endodontic sealer, can contribute to the long-term success of endodontic therapy by combating the re-infection of a tooth and promoting the healing of the periapical bone. The objective of this study was to measure the release of boron, strontium, and silicon ions from surface pre-reacted glass ionomer (S-PRG) filler containing prototype endodontic sealer over a sustained period in comparison to EndoSequence BC sealer in a simulated clinical model using extracted human teeth in vitro. METHODS: Twelve extracted human anterior teeth were instrumented using ProTaper Next (Dentsply Sirona, Johnson City, TN, USA) files up to size X3 (#30/variable taper) with copious 2.5% NaOCl irrigation. Teeth were obturated using a single-cone technique with a matching size tapered gutta-percha point and one of two endodontic sealers: prototype S-PRG (Shofu Inc., Kyoto, Japan) or EndoSequence BC (Brasseler, Savannah, GA, USA). The teeth were soaked in phosphate-buffered saline (PBS) solution for 336 hours. Periodically, 1-mL samples of the PBS were analyzed via an inductively coupled plasma mass spectrometer to determine the concentrations of ions released by the sealers. RESULTS: The average (S.D.) cumulative release (ng/ml) of boron, silicon, and strontium ions over 2 weeks for the prototype S-PRG sealer was 8614.9 (1264.3), 35758.9 (5986.5), and 3965.2 (145.6), and for EndoSequence BC sealer was 1860.5 (82.7), 164648.7 (16468.1), and 227.7 (4.7). Generalized linear mixed model analysis showed significant differences in ion concentration among boron, silicon, and strontium over time between the two sealer groups (Boron: P<0.0001, Silicon: P=0.010, Strontium: P=0.028). Of the three ions, strontium had the lowest amount of release for both sealers. The prototype S-PRG sealer showed a rapid initial burst followed by a slow, continuous release of strontium ions. CONCLUSION: The prototype S-PRG sealer released boron and strontium ions in higher cumulative concentrations over 2 weeks compared to the EndoSequence BC sealer. Both the prototype S-PRG and EndoSequence BC sealers released silicon ions, although significantly more were eluted from the EndoSequence BC sealer. Antimicrobial and osteogenic ion release from sealers is expected to positively influence the post-treatment control of microbial infections to improve periapical healing.

Micro-computed tomographic evaluation of single-cone obturation with three sealers.

OBJECTIVES: This study used micro-computed tomography (µCT) to compare voids and interfaces in single-cone obturation among AH Plus, EndoSequence BC, and prototype surface pre-reacted glass ionomer (S-PRG) sealers and to determine the percentage of sealer contact at the dentin and gutta-percha (GP) interfaces. MATERIALS AND METHODS: Fifteen single-rooted human teeth were shaped using ProTaper NEXT size X5 rotary files using 2.5% NaOCl irrigation. Roots were obturated with a single-cone ProTaper NEXT GP point X5 with AH Plus, EndoSequence BC, or prototype S-PRG sealer (n = 5/group). RESULTS: The volumes of GP, sealer, and voids were measured in the region of 0-2, 2-4, 4-6, and 6-8 mm from the apex, using image analysis of sagittal µCT scans. GP volume percentages were: AH Plus (75.5%), EndoSequence BC (87.3%), and prototype S-PRG (94.4%). Sealer volume percentages were less: AH Plus (14.3%), EndoSequence BC (6.8%), and prototype S-PRG (4.6%). Void percentages were AH Plus (10.1%), EndoSequence BC (5.9%), and prototype S-PRG (1.0%). Dentin-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 82.4% ± 6.8%, 71.6% ± 25.3%, and 70.2% ± 9.4%, respectively. GP-sealer contact ratios of AH Plus, EndoSequence BC, and prototype S-PRG groups were 65.6% ± 29.1%, 80.7% ± 25.8%, and 87.0% ± 8.6%, respectively. CONCLUSIONS: Prototype S-PRG sealer created a low-void obturation, similar to EndoSequence BC sealer with similar dentin-sealer contact (> 70%) and GP-sealer contact (> 80%). Prototype S-PRG sealer presented comparable filling quality to EndoSequence BC sealer.

Micro CT pilot evaluation of removability of two endodontic sealers.

PURPOSE: This study compared the removability of AH Plus and EndoSequence BC sealers using in vitro micro-computed tomography. METHODS: Ten single-canal, extracted human teeth were cleaned and shaped with ProTaper NEXT rotary files to size X5 (50/0.06) (Dentsply-Sirona). Canals were obturated with a single cone gutta-percha and either AH Plus (Dentsply-Sirona) (Group A) or EndoSequence BC (Brasseler) (Group B). ProTaper Universal Retreatment files (Dentsply-Sirona) were used to remove obturation materials after 90 days at 37oC/100% humidity. Each tooth was scanned using micro-computed tomography (SkyScan 1272; Bruker) at an isotropic resolution of 6 µm from which the percent of material removed was calculated. Two-sample t-tests and one-way ANOVA were used for analysis. RESULTS: The percent removal of materials in the coronal third was 92.9% ± 7.3% (Group A) and 93.2% ± 6.1% (Group B). Removal in the middle third was 94.9% ± 8.5% (Group A) and 96.5% ± 6.1% (Group B). Apical third removal was 76.2% ± 27.9% (Group A) and 70.1% ± 30.8% (Group B). No statistically significant differences were determined between the two sealers or among the sectional thirds within each group (P > 0.05). CONCLUSION: AH Plus and EndoSequence BC sealers exhibit the same removability at all canal levels of 70% to 96%, with better removal coronally.

PRECEDE-PROCEED model modification in community-based oral health promotion by using the linear structural relations programme.

PURPOSE: The PRECEDE-PROCEED (P-P) model is a framework for designing health education/promotion programmes. While the P-P model has been used to design community-based oral health programmes, outcome assessments of the model are seldom reported. The aim of the present study was to explore whether pathways in the P-P model accurately reflect the current status of environmental/behavioural assessment in a Japanese community and to examine whether using the linear structural relations (LISREL) programme would improve the model. MATERIALS AND METHODS: In a community health centre in Japan, a questionnaire with 29 items regarding oral health was distributed to 824 mothers with 3-year-old children. The items were compiled into eight variables that were tested using the LISREL programme. Goodness-of-fit index (GFI), adjusted goodness-of-fit index (AGFI) and root mean square error of approximation (RMSEA) were statistically analysed before and after P-P model modification. RESULTS: The GFI, AGFI and RMSEA were 0.913, 0.776 and 0.161 before, and 0.975, 0.939 and 0.075 after P-P model modification, respectively. Indirect effects on the quality of life from the predisposing, reinforcing and enabling factors became stronger than those in the initial P-P model. The overall fit of the modified P-P model was significantly better than that of the P-P model without modification, which did not accurately reflect the status of environmental/behavioural assessment in the community. CONCLUSIONS: The modified P-P model reflected the current status of environmental/behavioural assessment in the community. Health education models should be tested rigorously to ensure that they fit the reality of people's behaviour.

Comprehensive review of current endodontic sealers.

Endodontic sealers for non-surgical root canal treatment (NSRCT) span many compositions and attributes. This comprehensive review discusses current types of endodontic sealers by their setting reaction type, composition, and properties: zinc oxide-eugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealers. Setting time, solubility, sealing ability, antimicrobial, biocompatibility, and cytotoxicity are all aspects key to the performance of endodontic sealers. Because sealing ability is so important to successful outcomes, the relative degree of microleakage among all the relevant sealers was calculated by way of a meta-analysis of relevant literature. Compared to AH Plus, tricalcium silicate sealers show the lowest relative microleakage among the sealers assessed, followed by silicone sealers and other non-AH Plus epoxy resin sealers. Tricalcium silicate sealers also exhibit the most favorable antimicrobial effect and excellent biocompatibility. Future sealers developed should ideally combine a hermetic seal with therapeutic effects.

Pink Tooth of Mummery in the Maxillary Left Canine after Fixed Partial Denture (FPD) Preparation.

Pink tooth of Mummery is typically found after trauma. However, this case report describes an unusual occurrence of pink tooth in a 67-year-old Caucasian male after fixed partial denture (FPD) tooth preparation. Pink tooth in this case may be due to one or more factors: tooth reduction and heat generation during tooth preparation; heat generation during polymerization of provisional material; and hyperocclusion of a provisional FPD. This case highlights the importance of choosing the appropriate materials and techniques to avoid pulpal complications after dental prosthesis work.

Comparative analysis of the particle size and shape of commercially available mineral trioxide aggregates and Portland cement: a study with a flow particle image analyzer.

The aim of this study is to characterize the particle size distribution and circularity of various Mineral Trioxide Aggregates (MTA) (ProRoot MTA/ MTA Angelus/Gray and White) and Portland cements with effective size ranges of 1.5-160 microm using a flow particle analyzer (Sysmex FPIA-3000, Kobe, Japan). Cumulative percentage of particles between 6 and 10 microm were, 65, 73, 48, 53, and 70 %, for Gray ProRoot MTA, White ProRoot MTA, Gray MTA Angelus, White MTA Angelus, and Portland cement, respectively. ProRoot MTA contains fewer large particles than MTA Angelus. MTA Angelus contains a higher number of small particles than ProRoot MTA. White MTA contains smaller particles with a narrower range of size distribution than Gray MTA. MTA Angelus particles have relatively low circularity and wide size distribution and are less homogeneous than ProRoot MTA.

Dental education in Peru.

This paper provides information about Peru's dental history and dental school system, including the curriculum and dental licensure. With the increase in the number of dental schools in Peru, the number of dentists is also increasing. Until 1965, Peru had only three dental schools; currently, there are 14. Four of these dental schools are public, and ten are private. A five- or six-year dental program leads to the B.D.S. degree. After successful completion of a thesis defense or competency examination, the D.D.S. degree is awarded. The D.D.S. is mandatory for practicing dentistry in Peru. Currently, there are approximately 14,000 active dentists, with a dentist-patient ratio of approximately 1:2,000.

Dental education in Malaysia.

There was only one dental school in Malaysia until 1997 but five new schools have been established since 1998. This review provides information about dental education in Malaysia including; the history of dental education, the current dental school system and curriculum, and dental licensure. There are four public and two private dental schools in Malaysia. High school graduates are required to take the nationwide matriculation entrance examination or the Higher School Certificate (HSC) to apply for a dental degree programme. A five-year dental programme leads to the BDS or the DDS degree. National or state examinations are not required to practise dentistry. Currently, there are approximately 2,500 dentists, with a ratio of 1 dentist for every 10,000 people.

Education of dentists in Thailand.

Thailand is geographically located in southeast Asia and its population is 63 million. Little has been published on dental education in Thailand. This paper provides information about Thailand regarding its dental history, dental school system including curriculum and dental licensure. There are eight public and one private dental school in Thailand. A six-year dental education leads to the DDS degree. On graduation from the public dental schools, dentists are required to work in the public system for three years. Currently, there are approximately 8000 active dentists, with a dentist: population ratio of approximately 1:7000.

Comparison of apical centring ability between incisal-shifted access and traditional lingual access for maxillary anterior teeth.

The aim of this study was to compare the apical centring ability of incisal-shifted access (ISA) with that of traditional lingual access (TLA). Fifteen three-dimensional printed resin models were prepared from the computed tomography data for a human maxillary central incisor and divided into ISA (n = 7), TLA (n = 7) and control (n = 1) groups. After access preparation, these models were shaped to the working length using K-files up to #40, followed by step-back procedures. An apical portion of the model was removed at 0.5 mm coronal to the working length. Microscopic images of each cutting surface were taken to measure the preparation area and the distance of transportation. TLA created a larger preparation area than ISA (P < 0.05). The distance of transportation (mean ± standard deviation) was 0.4 ± 0.1 mm for ISA and 0.7 ± 0.1 mm for TLA (P < 0.05). Access cavity preparation has a significant effect on apical centring ability. ISA is beneficial to maintaining apical configuration.

Education of dentists in China.

China is geographically located in the east of Asia and its population exceeds 1.3 billion. An understanding of dental education in China is thus of interest. However, as there is little published information on this topic, this paper provides information about China regarding its dental history, dental school system including curriculum and dental licensure. High school graduates take a nationwide entrance examination to apply for dental school, of which there are more than 50 in China. A five year dental education leads to the BDS degree. Dental school graduates must then pass the nationwide licensure examination to practise dentistry. Currently, there are not adequate numbers of dentists to provide the necessary oral health care for people living outside metropolitan areas.

The hierarchical cluster analysis of oral health attitudes and behaviour using the Hiroshima University--Dental Behavioural Inventory (HU-DBI) among final year dental students in 17 countries.

OBJECTIVE: To explore and describe international oral health attitudes/ behaviours among final year dental students. METHODS: Validated translated versions of the Hiroshima University-Dental Behavioural Inventory (HU-DBI) questionnaire were administered to 1,096 final-year dental students in 17 countries. Hierarchical cluster analysis was conducted within the data to detect patterns and groupings. RESULTS: The overall response rate was 72%. The cluster analysis identified two main groups among the countries. Group 1 consisted of twelve countries: one Oceanic (Australia), one Middle-Eastern (Israel), seven European (Northern Ireland, England, Finland, Greece, Germany, Italy, and France) and three Asian (Korea, Thailand and Malaysia) countries. Group 2 consisted of five countries: one South American (Brazil), one European (Belgium) and three Asian (China, Indonesia and Japan) countries. The percentages of 'agree' responses in three HU-DBI questionnaire items were significantly higher in Group 2 than in Group 1. They include: "I worry about the colour of my teeth."; "I have noticed some white sticky deposits on my teeth."; and "I am bothered by the colour of my gums." CONCLUSION: Grouping the countries into international clusters yielded useful information for dentistry and dental education.