[show abstract][hide abstract] ABSTRACT: Optical coherence tomography (OCT) is a potential clinical tool for enamel lesion monitoring. Swept-source OCT findings were compared with cross-sectional nanohardness findings of enamel. Subsurface bovine enamel lesions in three groups were subjected to (1) deionized water (control), (2) phosphoryl oligosaccharide of calcium (POs-Ca) or (3) POs-Ca with 1 ppm fluoride for 14 days. B-scans images were obtained at 1310-nm center wavelength on sound, demineralized and remineralized areas after 4, 7, and 14 days. The specimens were processed for cross-sectional nanoindentation. Reflectivity from enamel that had increased with demineralization decreased with remineralization. An OCT attenuation coefficient parameter (μt), derived based on the Beer-Lambert law as a function of backscatter signal slope, showed a strong linear regression with integrated nanohardness of all regions (p<0.001, r=-0.97). Sound enamel showed the smallest, while demineralized enamel showed the highest μt. In group three, μt was significantly lower at four days than baseline, but remained constant afterwards. In group two, the changes were rather gradual. There was no significant difference between groups two and three at 14 days in nanohardness or μt POs-Ca with fluoride-enhanced nanohardness of the superficial zone. OCT signal attenuation demonstrated a capability for monitoring changes of enamel lesions during remineralization.
Journal of Biomedical Optics 04/2013; 18(4):46006. · 2.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Early detection, monitoring and remineralization repair of enamel
lesions are top research priorities in the modern dentistry focusing on
minimal intervention concept for caries management. We investigate the
use of swept-source optical coherence tomography system (SS-OCT) without
polarization-sensing at 1319 nm wavelength developed for clinical
dentistry (Dental OCT System Prototype 2, Panasonic Healthcare Co.,
Ltd., Japan) in quantitative assessment of artificial enamel lesions and
their remineralization. Bovine enamel blocks were subjected to
demineralization to create subsurface lesions approximately 130 μm in
depth over 2 weeks, and subjected to remineralization in solution
containing bioavailable calcium and 1ppm fluoride at pH 6.5 for 2 weeks.
Cross-sectional images of sound, demineralized and remineralized
specimens were captured under hydrated conditions by the OCT. Finally,
the specimens were cut into sections for nanoindentation to measure
hardness through the lesion under 2mN load. Reflectivity had increased
with demineralization. OCT images of lesions showed a boundary closely
suggesting the lesion depth that gradually progressed with
demineralization time. After remineralization, the boundary depth
gradually decreased and nanoindentation showed over 60% average hardness
recovery rate. A significant negative correlation was found between the
slope power-law regression as a measure of attenuation and overall
nanohardness for a range of data covering sound, demineralized and
remineralized areas. In conclusion, OCT could provide clear images of
early enamel lesion extent and signal attenuation could indicate its
severity and recovery. Clinical data of natural lesions obtained using
Dental OCT and analyzed by this approach will also be presented. Study
supported by GCOE IRCMSTBD and NCGG.
Proc. SPIE. 8566, Lasers in Dentistry XIX 856602; 03/2013
[show abstract][hide abstract] ABSTRACT: This study aimed to evaluate effectiveness of Phosphoryl-Oligosaccharides of Calcium (POs-Ca) added to apple juice on enamel erosion. Five juices were prepared by adding 0%, 0.5%, 1%, 1.5% or 2% POs-Ca to commercial apple juice, and subjected to Visual Analogue Scale (VAS) taste evaluation and pH and calcium/inorganic-phosphates analyses. To evaluate erosion, polished bovine enamel blocks were immersed in each juice for 5 or 60 min (n=20). Enamel surface loss (SL) and roughness (Ra) were also analyzed. VAS indicated acceptable taste for juices containing up to 1% POs-Ca. POs-Ca addition resulted in increased pH (3.61-3.88), calcium (0.95-25.10 mM), and inorganic-phosphate (1.77-20.44 mM). After 5 min, 0% juice resulted in significant erosion (p<0.05). However even after 60 min, no significant increase was found in Ra and SL compared to water (control) for 1.5-2% juices (p>0.05). Addition of 1-1.5% POs-Ca could significantly reduce enamel erosion by apple juice maintaining an acceptable taste.
[show abstract][hide abstract] ABSTRACT: A low pH environment is created by cariogenic bacteria. This study was aimed to measure pH of carious lesions intraorally using a micro-pH sensor, and assess predominant acid-producing cariogens by qPCR to differentiate caries activities.
103 dentine lesions classified as active or arrested caries based on the clinical and radiological examinations were collected from patients after intraoral measurement of the lesion surface pH using a micro-pH sensor. Quantitative detection of genomic DNA copies of target cariogenic bacteria (mutans streptococci and Lactobacillus spp.) in each lesion was performed using real-time PCR. Correlation between the pH ranges and the number of bacterial species was examined by Spearman test.
50 samples were diagnosed as active and 53 as arrested lesions. Statistically significant difference was observed on average surface pH value between active and arrested lesions (p<0.05). Prevalence of Lactobacillus spp. was higher in active lesions than in arrested lesions (76% vs. 58% of samples, respectively). When the carious lesions were categorised into four different pH ranges (up to 5.5, from 5.6 to 5.8, from 5.9 to 6.1 and 6.2 or above), increased prevalence of Lactobacillus spp. was observed with decrease of pH levels. A significant negative relationship was found between pH value and number of Lactobacillus spp. (r=-0.209, p<0.05) but no such correlation was found for mutans streptococci.
Intraoral pH measurement might be clinically useful to determine acidity of the local environment of carious lesions as one aspect of the caries activity assessment.
The population of certain bacteria may indicate activity of carious lesions. Intraoral pH measurement of the carious lesions using a micro-pH sensor may be a clinically feasible method for assessment of lesion acidity.
Journal of dentistry 03/2012; 40(3):222-8. · 2.00 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim of this study was to assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and a low concentration of fluoride (F) on the hardness of enamel subsurface lesions, utilizing a double-blind, randomized, and controlled in situ model. Fifteen individuals wore removable lingual appliances with 3 bovine-enamel insets containing subsurface demineralized lesions. Three times a day for 14 days, they chewed one of the 3 chewing gums (placebo, POs-Ca, POs-Ca+F). After the treatment period, cross-sectional mineral content, nanoindentation hardness, and fluoride ion mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS) were evaluated. Although there were no statistical differences in overall mineral content and hardness recovery rates between POs-Ca and POs-Ca+F subsurface lesions (p > 0.05), nanoindentation at 1-μm distance increments from the surface showed statistical differences in hardness recovery rate between POs-Ca and POs-Ca+F in the superficial 20-μm region (p < 0.05). Fluoride mapping revealed distribution of the ion up to 20 μm from the surface in the POs-Ca+F group. Nanoindentation and TOF-SIMS results highlighted the benefits of bioavailability of fluoride ion on reinforcement of the superficial zone of subsurface lesions in situ (NCT01377493).
Journal of dental research 02/2012; 91(4):370-5. · 3.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: Manufacturers are adding fluoride (F) to calcium-containing chewing gums to further promote enamel remineralization. The aim of this study was to assess the effect of a chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and fluoride on remineralization of enamel subsurface lesions, in a double-blind, randomized controlled in situ trial.
Thirty-six volunteer subjects wore removable buccal appliances with three different insets of bovine enamel with subsurface demineralized lesions. For 14 days the subjects chewed one of the three chewing gums (placebo, POs-Ca, POs-Ca+F), three times a day. After each treatment period, the insets were removed from the appliance, embedded, sectioned, polished and then subjected to laboratory tests; mineral level was determined by transverse microradiography (TMR; n=36), and hydroxyapatite (HAp) crystallites were assessed by synchrotron radiation wide-angle X-ray diffraction (WAXRD; n=13). Data were analysed by t-test or Wilcoxon rank-sum test with Bonferroni corrections at 0.05 significance level.
Chewing POs-Ca and POs-Ca+F gums resulted in 21.9±10.6 and 26.3±9.4 (mean±SD) percentage mineral recovery, which was significantly higher than that of placebo gum (15.0±11.4) (p<0.05). Chewing POs-Ca+F gum resulted in 24.9±5.4 (mean±SD) percentage HAp crystallites recovery, which was significantly higher compared to POs-Ca (16.0±4.1%) or placebo (11.1±4.8%) gums (p<0.05).
Addition of POs-Ca to the chewing gum resulted in significant remineralization of enamel subsurface lesions. Although POs-Ca+F gum was not superior in TMR recovery rate when compared with POs-Ca gum, WAXRD results highlighted the importance of fluoride ion bioavailability in the formation of HAp crystallites in enamel subsurface lesions in situ (NCT01377493).
Journal of dentistry 08/2011; 39(11):771-9. · 2.00 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study aimed to assess dentin bond durability of 4-META/MMA-TBB resin cement over ten years, by evaluating the tensile bond strength, and SEM and TEM observations. Tensile bond strength of Super Bond C&B (SB) to bovine dentin was evaluated at 1 day and after 10 years. The mode of failure after debonding was observed by SEM. Interfacial ultrastructure and nanoleakage was observed by TEM at the baseline and after 10 y. The tensile bond strength significantly dropped after 10 y. The failure pattern shifted from cohesive failure in resin towards adhesive failure or cohesive failure in dentin. TEM observation revealed degradation of both resin and collagen networks within the hybrid layer and nanoleakage at the base of the hybrid layer after 10 y. The bond strength of SB to dentin significantly decreased, and the hybrid layer degraded, while the overlying hydrophobic resin layer showed little disintegration over 10 y.
[show abstract][hide abstract] ABSTRACT: This study aimed to evaluate enamel surface roughness (Ra) and pH before and after erosion by soft drinks. Enamel was exposed to a soft drink (cola, orange juice or green tea) for 1, 5 or 60 min; Ra was measured using contact-stylus surface profilometry (SSP) and non-contact focus variation 3D microscope (FVM). Surface pH was measured using a micro pH sensor. Data were analyzed at significance level of alpha=0.05. There was a significant correlation in Ra between SSP and FVM. FVM images showed no changes in the surface morphology after various periods of exposure to green tea. Unlike cola and orange juice, exposure to green tea did not significantly affect Ra or pH. A significant correlation was observed between surface pH and Ra change after exposure to the drinks. Optical surface analysis and micro pH sensor may be useful tools for non-damaging, quantitative assessment of soft drinks erosion on enamel.
[show abstract][hide abstract] ABSTRACT: The aim of this study was to establish a new in vitro model for biofilm induced secondary caries studies using an oral biofilm reactor.
An approximately 2 × 3 × 2 mm(3) sized dentino-enamel Class I cavity was prepared in the middle of a square-shaped specimen from the mid-labial portion of bovine incisors. The cavities were partially filled with either Clearfil AP-X with SE-Bond or Clearfil AP-X without any bond. Artificial biofilms were then formed on the resin composite filled surfaces using three species of oral bacteria in an oral biofilm reactor for 20 hours followed by 7- or 30-day incubation periods.
The lesions were clearly visible on fluorescence microscopy and by scanning electron microscopy in the enamel at the interface of resin restorations in all samples. The data from image analysis showed that the lesion size was largest in the No-bond samples with statistically significant differences (p < 0.05). Demineralization along the cavity wall extended deeper in No-bond compared to SE-Bond samples and penetration was significantly deeper in No-bond 30-day samples.
A primary artificial secondary caries model was established using biofilms for in vitro studies and the significance of using a bonding system could also be verified.
Australian Dental Journal 03/2011; 56(1):40-7. · 1.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aims of this study were to clarify which steps in approximal restorative procedure were difficult for the final-year undergraduate students at Tokyo Medical and Dental University, and to examine the relationship between perception of difficulty and clinical experience. At mid-term of the clinical education experience, a self-questionnaire was performed by final-year undergraduate students to clarify the difficulty of restorative procedures at the time. There were statistically significant differences in the number of clinical cases experienced at the time between students who designated the matrix application, shade selection and finishing as the easy steps and those who considered them as the difficult ones (Fisher exact test with Bonferroni correction, p < 0.05). There was a significant difference in the total number of procedures designated as difficult between students who had treated above 15 cases and those who had fewer than 15 cases (Wilcoxon rank-sum test, p< 0.05). In the final-year clinical education for operative dentistry, students might need to treat over 15 cases to gain confidence in performing approximal composite restorations independently.
Journal of medical and dental sciences 01/2011; 58(1):1-5.
[show abstract][hide abstract] ABSTRACT: Means of objectively assessing white spot enamel lesions (WSEL) are critical for determining their potential activity and monitoring the success of preventive treatments. The aim of this study was to determine whether surface pH measurements of WSEL changed during a preventive course of care designed to remineralize the lesions.
Eight healthy subjects (1 male and 7 females) with at least one WSEL were recruited (19-64 years). Each subject was placed on a preventive treatment program including the daily application of a CPP-ACP paste (MI paste, GC Corp., Japan) with custom fitted trays for more than 6 months. The surface pH values of sound enamel and WSEL were monitored for up to 2 years using a micro-pH sensor. The visual appearance of the WSEL was monitored via digital photography, and images were analyzed qualitatively on a 5-point scale to assess the success of the remineralization preventive program. The relationship between the qualitative assessment of WSEL appearance and the WSEL pH was investigated using a Spearman's rho non-parametric correlation.
The surface pH of the WSEL was different to that of the sound enamel surrounding it in all patients at all times. All lesions showed visual improvement as the treatment period progressed. The pH of the WSEL increased towards that of sound enamel over the course of treatment significantly correlating with the visual improvement of the lesion (rho=0.63, p<0.0001).
The clinical assessment of WSEL surface pH changes with time may have utility as an additional objective measure for the assessment of WSEL activity.
Journal of dentistry 07/2010; 38(7):584-90. · 2.00 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the pretreatment effect of mild acidic HOCl solution on the microtensile bond strength (muTBS) of a two-step self-etch adhesive to dentin and the alteration of dentin surface pH.
Thirty-nine flat ground coronal dentin specimens were divided into one control group and 12 experimental groups, which were treated with 6% NaOCl or 50, 100 and 200ppm HOCl (Comfosy) solutions for 5, 15 and 30s. After rinsing with running water for 30s, all the dentin surfaces were bonded with Clearfil SE Bond according to the manufacturer's instructions. After 24h water storage, the bonded specimens were sectioned and trimmed to an hourglass shape with a cross-sectional area of approximately 1.0mm(2) and then subjected to the muTBS test. Thirty-six mid-coronal dentin discs were used for surface pH measurement. Dentin surface pH with or without pretreatment was examined using a pH-imaging microscope (SCHEM-100). The muTBS data were analyzed by one-way ANOVA (Dunnett's T3) and the surface pH data were analyzed by non-parametric statistics (Mann-Whitney U-test).
Pretreatment with Comfosy at concentrations of 50, 100 and 200 ppm did not significantly affect muTBS regardless of the application time compared with the control group, however the 100 and 200ppm Comfosy groups showed significantly lower surface pH values. For the NaOCl pretreatment groups, a longer application time significantly decreased the muTBS and increased the surface pH values compared to the control group.
The 50ppm Comfosy pretreatments for 5, 15 and 30s did not affect the muTBS of the two-step self-etch adhesive to dentin and dentin surface pH.
Journal of dentistry 11/2009; 38(3):261-8. · 2.00 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim of this study was to adapt a quantitative test for stimulated saliva, known as the Checkbuf test, to measure the buffering capacity of resting saliva and to evaluate its correlation with the Ericsson test for resting saliva.
Resting saliva was collected from 112 patients. Buffering capacity was assessed with the adapted Checkbuf test and 4 other methods: Ericsson test for resting saliva, Checkbuf test, and commercially available paper and liquid colorimetric tests for stimulated saliva. Data were analyzed by Cohen kappa coefficient to evaluate the agreement between the Ericsson test and the other tests.
There was a significant positive agreement between the Ericsson test for resting saliva and adapted Checkbuf test (kappa = 0.708). However, there were no agreements between the Ericsson test and the 3 other tests.
This study demonstrated that the adapted Checkbuf test is useful for measuring resting saliva buffering capacity, even for subjects with low salivary flow rates.
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to evaluate the micro-shear bond strengths and the etching efficacy of a two-step self-etching adhesive system to fluorosed and non-fluorosed enamel. The extracted teeth, obtained from Australian and Japanese patients, were classified according to the severity of fluorosis, using the Thylstrup & Fejerskov index (TFI). Australian teeth were classified as mildly fluorosed (TFI = 1-3), whereas Japanese teeth were classified as non-fluorosed (TFI = 0). Resin composite was bonded to 20 enamel samples using Clearfil SE bond. The bonded samples were stressed at a crosshead speed of 1 mm min(-1) to determine the micro-shear bond strength. To examine the etching efficacy of primer on fluorosed and non-fluorosed enamel, the enamel-surface pH values were directly measured using a micro pH sensor. The non-fluorosed enamel showed significantly higher bond strengths compared with the fluorosed enamel. There was a statistical difference between fluorosed and non-fluorosed enamel regarding the surface pH change before and after application of the Clearfil SE bond primer. The results from this study suggest that water fluoridation has an effect on the acid resistance of enamel surfaces when treated with a two-step self-etching adhesive system and that this effect leads to reduced bond strengths.
European Journal Of Oral Sciences 05/2009; 117(2):182-6. · 1.42 Impact Factor
[show abstract][hide abstract] ABSTRACT: The ion activity product for hydroxyapatite (Ip(HA)) is a comprehensive parameter reflecting pH, calcium and phosphate ion concentration in saliva which govern the degree of saturation with respect to the dissolving tooth mineral. The aim of this study was to evaluate the relationship between quantitative assessments of salivary buffering capacity and Ip(HA) in relation to cariogenic potential.
Stimulated whole saliva was collected from 33 patients, and the initial pH of samples was measured using a hand-held pH meter. Then samples were titrated with 0.1 N HCl to evaluate buffering capacities and divided into three groups (high, medium and low). After measuring concentrations of calcium and phosphate ions in the samples, Ip(HA) was calculated using the values of the ion concentrations and pH. Differences in the mean pH values, the concentrations of calcium, phosphate ions and log[Ip(HA)] among three groups were analysed using the Kruskal Wallis and the Mann-Whitney non-parametric test, p < 0.05.
After HCl 50 microL titration, there were statistical differences of the mean pH and Ip(HA) among each buffering capacity group. Moreover, after 50 microL HCl titration, there was an excellent correlation between the buffer capacity and log[Ip(HA)].
The pH change for saliva after HCl titration has a significant influence on the rate of Ip(HA).
Australian Dental Journal 06/2008; 53(2):167-71. · 1.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: In 1959, Ericsson developed a laboratory buffer capacity test. Because the Ericsson test is not practical for use as a chair-side test, commercially available saliva buffering capacity tests have been developed for use in the dental office. The purpose of this study was to evaluate the correlation between a modified Ericsson test and three commercially available quantitative and colourimetric tests.
Stimulated saliva (by chewing paraffin wax) was collected from 113 patients. Individual saliva buffering capacity was assessed with the following four different methods: modified Ericsson test; quantitative test using a hand-held pH meter; paper strip; or liquid colourimetric test. The correlations of ranking results among the different tests were analysed using the Spearman Rank Correlation Test, p < 0.001.
Spearman Rank Correlation indicated significant positive coefficients between the modified Ericsson test and the quantitative test (rho = 0.857), the paper strip colourimetric test (rho = 0.621) and the liquid-type colourimetric test (rho = 0.689).
The detection level of medium and high buffering capacity was test dependent. The quantitative test using a hand-held pH meter showed a stronger positive correlation with the modified Ericsson test. The qualitative tests seemed less reliable, particularly for patients classified as having a medium buffering capacity.
Australian Dental Journal 06/2008; 53(2):140-4. · 1.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the pulp healing to bacterial contamination beneath a hard-setting calcium hydroxide (DY: Dycal, L.D. Caulk Co.) and a self-etching adhesive resin (2V: Clearfil Liner Bond 2V, Kuraray Medical Inc.) following dentin bridge formation. Class V cavities were prepared on 30 monkey teeth, and the pulps were exposed with a carbide bur through the cavity floor. Each exposed pulp was capped with either DY or 2V. The cavities were restored with a hybrid resin composite. The resin composite was removed at 180 days after capping, and then cavities were left open to the oral environment for 2 weeks to obtain bacteria contamination DY (BDY) and 2V (B2V; n = 10). A non-bacterial-contaminated group capped with DY was used as control. After bacterial challenges, inflammatory cell infiltration, incidence and differentiation of dentin bridges were evaluated histologically. There were significant differences in the presence of inflammatory cell infiltration among all groups (P < 0.05). No moderate or severe inflammatory reaction was found in Group DY. Group BDY showed moderate or severe inflammatory cell infiltration in 50%, and showed four necrotic specimens. Although no statistically significant difference was found in the formation and differentiation of dentin bridges among all groups, tunnel defects in dentin bridges were detected in 70% (DY), 80% (BDY), and 50% (B2V). Group B2V showed a significantly lower presence of inflammatory cell infiltration than Group BDY (P < 0.05). Bonding agent is supposed to seal the exposure site, and the remaining bonding agent on the cavities was effective as the barrier in the dentin bridges after bacterial challenges.
[show abstract][hide abstract] ABSTRACT: A missing incisor or premolar tooth that requires a quick functional and esthetic repair, such as the case of tooth loss caused by trauma needs quick conservative treatment to maintain sound abutment teeth. The use of resin composite for direct fixed partial denture (FPD) can reduce problems associated with metal substructures, such as esthetic limitations and preparation of abutment teeth. However, mechanical failure of direct FPD often occurs because of design limitations and poor fabrication. This case report describes a direct resin composite FPD combined with an orthodontic wire framework. A small enamel dimple was prepared below the contact area, and a U-shaped wire was formed and positioned in the prepared enamel dimples and bonded with resin cements. An alloy primer was applied to the surface of the wire, which was coated with adhesive resin and veneered with resin composite. The finishing of the margins and final polishing were completed a week after insertion. The FPD was contoured using fine composite diamond finishing burs and polished with silicone points. The combination of the U-shaped wire and an enamel dimple below the contact area has shown good results over a period of more than 12 months in these two cases.
[show abstract][hide abstract] ABSTRACT: To evaluate the effect of resin coating of bonded dentin on the micro-tensile bond strengths of a resin cement to dentin over 1 year.
Human molars were ground to obtain flat dentin surfaces and divided into three groups. The dentin surfaces were left as a control, or resin-coated with a combination of a dentin bonding system, Clearfil SE Bond (SE), and one of two lining materials: Protect Liner F (PLF) (SE/PLF) or Ionosit Micro Spand (IMS). The dentin surfaces with or without resin coating were covered with a temporary filling material (Cavit-G) and stored in water for 1 day. After removal of Cavit-G, an indirect composite block (Estenia) was bonded with Panavia F following the manufacturer's instructions. The specimens were stored in water for 1 day, 6 months or 1 year in 37 degrees C water. Micro-tensile bond strength was measured at a crosshead speed of 1 mm/minute. There were 10 slices each group. Data were analyzed with two-way ANOVA and Fisher's PLSD test (P < 0.05).
ANOVA indicated that resin coating and storage period significantly influenced the micro-tensile bond strengths (P < 0.0001). The bond strengths of SE/PLF, SE/IMS and the control after 1 day were 27.5 +/- 5.1, 15.7 +/- 3.2 and 10.6 +/- 4.9 MPa, respectively. The bond strengths of SE/PLF significantly decreased over 1 year (P < 0.05), while there were no significant differences in bond strengths for SE/IMS (P > 0.05). The bond strengths of SE/PLF were significantly higher than those of the control over 1 year (P < 0.05).
American journal of dentistry 02/2008; 21(1):64-8. · 1.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: To assess the 10-year clinical performance of resin composite restorations placed using the acid-etch technique.
Clinical evaluation of 58 resin composite restorations was performed by 9 operators of the Operative Dentistry Clinic of the Dental Hospital, Tokyo Medical and Dental University. Conservative preparations had been made and a total-etch adhesive system used for the resin composite restorations, which were placed in 1992 in the Operative Dentistry Clinic. Restorations were scored using the following scale: Alfa--good; Bravo--clinically acceptable; Charlie--clinically unacceptable; Delta-already replaced. The scores were analyzed using the chi-square test and the expected cell frequency (P = .05).
The 58 restorations from 26 patients (13 men and 13 women) were identified in the treatment records and analyzed. Twenty-two restorations (37.9%) presented Alfa scores and 17 restorations (29.3%) were clinically acceptable (Bravo scores), while 3 restorations (5.2%) received Charlie scores and 16 restorations (27.6%) had already been replaced (Delta scores). The descending ranking of longevity by restoration type was Class 5 >Class 3 >Class 2 >Class 1 >Class 4 (P = .05).
Of the restorations evaluated, 67.2% were ser-viceable (combined Alfa and Bravo scores) 10 years after placement. Longevity was significantly influenced by cavity type.