Treatment effect of ozone and fluoride varnish application on occlusal caries in primary molars: a 12-month study.

AIM: The aim of this study is to evaluate the effect of ozone and fluoride varnish on occlusal caries in primary molars in a split-mouth study. MATERIALS AND METHODS: Caries risk was estimated by treating Public Dental Health Service dentists. Children with occlusal caries with Ekstrand index scores ≤3 (VI ≤3) were included. Selection of caries lesions was discontinued for ethical reasons due to non-acceptable clinical results during the follow-up. In the continued evaluation pairs of teeth with non-cavitated caries lesions, Ekstrand score ≤2a (VI ≤2) were selected. Fifty pairs of carious primary molars were included, 18 boys and 15 girls (mean 4.7 years, range 3-8). At baseline, the lesions were assessed by visual inspection (VI) and laser-induced fluorescence (LF), in each pair to treatment with 40 s ozone (HealOzone(TM), 2,100 ppm) or fluoride varnish Duraphat®. The treatments and evaluations were repeated at 3, 6 9 months and evaluations only at 12 months. RESULTS: Medium-high caries risk was observed in VI ≤3 children and low-medium risk in VI ≤2a children. In the 15 pairs VI ≤3 lesions, 8 treated with ozone and 9 with fluoride progressed to failure. In the 35 pairs VI ≤2a lesions, one lesion failed. Median baseline LF values in the VI ≤3 group were 76 and 69, for ozone and fluoride lesions, respectively, and 21 and 19 in the VI ≤2a group. At 12 months, LF values in the VI ≤2a group were 15 and 18. No improvement or difference in LF values was found over time between the caries lesions treated with ozone or fluoride. CONCLUSIONS: Neither ozone nor fluoride varnish treatments stopped the progression of caries in cavitated lesions. In low and medium caries risk children, non-cavitated lesions following both treatments showed slight or no progression. The use of ozone or fluoride varnish treatments in this regime as caries preventive method, added to the daily use of fluoridated toothpaste, to arrest caries progression in primary molars must therefore be questioned.

Antibacterial effect of ozone on cariogenic bacterial species.

OBJECTIVE: The aim was to evaluate the antibacterial effect of ozone on cariogenic bacterial species with and without the presence of saliva and a possible effect on the salivary proteins. METHODS: Suspensions of Actinomyces naeslundii (ACTCC 12104(T)), Lactobacilli casei (N CTC 151) and Streptococcus mutans (NCTC 10449), in salt buffer or in saliva, were exposed to ozone gas delivered by the ozone generator Healozone 2130C. Aliquots of the suspensions were taken after 10, 30 and 60s ozone exposures and cultivated on agar plates. Initial number of bacteria per ml was 8.0 x 10(7) (SD 2.2 x 10(7)) (A. naeslundii), 1.0 x 10(8) (SD 3.1 x 10(6)) (L. casei) and 1.0 x 10(8) (SD 7.0 x 10(5)) (S. mutans), respectively. The proteins were separated by SDS electrophoresis and visualized by silver staining. RESULTS: In salt buffer 92%, 73% and 64% of the initial numbers of A. naeslundii, S. mutans and L. casei, respectively, were killed already after 10s ozone exposure, while approximately 99.9% of the bacteria were dead after a 60s exposure. After 10 and 30s, but not after 60s exposure to ozone, S. mutans and L. casei were less efficiently killed in saliva compared to the salt buffer. Various saliva proteins were degraded by ozone after a 60s exposure. CONCLUSIONS: The cariogenic species S. mutans, L. casei and A. naeslundii were almost eliminated following 60s of ozone treatment. This killing was reduced in the presence of saliva although increasing the ozone application time to 60s overcame these reductants in saliva. Detection of altered salivary proteins indicates that saliva components constitute additional targets for ozone.

Mutans streptococci and lactobacilli in plaque on a leucite-reinforced dental ceramic and on a calcium aluminate cement.

In this in vivo study, the proportions of mutans streptococci and lactobacilli in plaque were examined (1) on proximal surfaces of bonded, leucite-reinforced ceramic crowns and (2) on class V restorations of calcium aluminate cement (CAC). The examined proportions were intraindividually compared with those of resin composite and enamel. Mutans streptococci and lactobacilli in samples from plaque that was accumulated for 10 days on the following surfaces were determined by cultivation on blood agar plates and species-selective plates: (1) proximal leucite-reinforced ceramic crown, class II composite and enamel (n=11); and (2) class V restoration of CAC and composite, and enamel (n=17). Mutans streptococci and lactobacilli in the samples were distributed in three groups: 0, >0-1, and >1% of total bacteria. The surfaces with detected mutans streptococci were similarly distributed between the materials and enamel. The highest proportion of mutans streptococci and lactobacilli were observed on ceramic followed by composite and enamel. A higher proportion of lactobacilli, but not of mutans streptococci, was detected on enamel compared to CAC and composite. However, no significant differences were found between the surfaces. Conclusively, the materials investigated did not show different relative proportions of mutans streptococci and lactobacilli in plaque, compared to enamel.

Effect of a hydroxyl ion-releasing composite resin on plaque acidogenicity.

The aim of this in vivo study was to evaluate the neutralizing capacity, registered as change of plaque acidogenicity, on aged proximal restorations of an ion-releasing composite resin (IRCR), which releases hydroxyl, calcium, and fluoride ions at low pH. Twenty patients, with a mean age of 63 years (range 43-85), participated. All had one aged proximal IRCR restoration (mean age 15 months) and one nonrestored enamel surface to make an intraindividual comparison possible. The neutralizing effect of the IRCR was evaluated by measuring plaque pH, using the microtouch method, after a mouthrinse with 10% sucrose. The plaque pH measurements were repeated 1.5 years later on the IRCR (mean age 34 months), the enamel surfaces and a universal hybrid composite resin (CR). At both 15 and 34 months, the plaque on the IRCR surfaces showed the least acidogenic potential for the whole 60-min time interval. The largest differences between the IRCR, CR and enamel were found during the first 15 min. At 15 months, the total areas under the plaque pH curve (AUC(5.7) and AUC(6.2)) differed significantly between the IRCR and enamel surfaces for the time periods 0-5 min and 5-15 min. At 34 months, significant differences were found between IRCR and CR at the 0- to 5-min time period. It can be concluded that IRCR restorations countered the plaque pH fall and maintained it at levels where less enamel and dentin demineralization can occur.

In vivo interfacial adaptation of class II resin composite restorations with and without a flowable resin composite liner.

The aim of this study was to evaluate in vivo the interfacial adaptation of class II resin composite restorations with and without a flowable liner. In 24 premolars scheduled to be extracted after 1 month, 48 box-shaped, enamel-bordered class II cavities were prepared and restored with a flowable liner (FRC, Tetric Flow/Tetric Ceram/Syntac Single-Component) or without (TRC), cured with three different curing modes: soft start and 500- or 700-mW/cm2 continuous irradiation. Interfacial adaptation was evaluated by quantitative scanning electron microscopic analysis using replica method. Gap-free adaptation in the cervical enamel (CE) was observed for FRC and TRC in 96.2 and 90.2%, for the dentin (D) in 63.6 and 64.9%, and for occlusal enamel (OE) in 99.7 and 99.5%, respectively. The difference between the two restorations was not statistically significant (ns). Significant better adaptation was observed for OE than CE and D (p<0.01), and for CE than D (p<0.01). Gap-free adaptation with the soft-start and 500- and 700-mW/cm2 continuous-curing modes was observed for CE: 88.7%, 92.7%, 97.9% (ns); OE: 99.8%, 98.7%, 100% (ns); and D: 64.0%, 63.9%, and 64.6% (ns), respectively. It can be concluded that neither the use of flowable resin composite liner nor the curing mode used influenced the interfacial adaptation.

Evaluation of a skin reference electrode used for intraoral pH measurements in combination with a microtouch electrode.

The aim of this in vivo study was to evaluate a skin reference electrode used with the microtouch method for measurements of intraoral pH. Registrations of plaque pH were made in ten healthy subjects before and up to 30 min after a mouth rinse with 10% sucrose. A microtouch electrode (Beetrode) was used in combination with two different half-cell reference electrodes: a skin silver-silver chloride plate or a glass capillary reference electrode. The skin electrode was placed on the subject's forearm in combination with a conductive gel. The glass capillary electrode, together with one of the test subject's fingers, was placed in a beaker with a 3 M KCl solution. High agreement between the two reference systems resulted in almost identical plaque-pH curves (r=0.97). The mean differences between the two systems at the different time points varied between -0.15 and +0.01 pH units, with an overall mean pH difference of 0.03 pH units. It can be concluded that the use of the skin reference electrode may very well replace the traditional reference electrode used in combination with a microtouch electrode for intraoral use.

Interfacial adaptation of a calcium aluminate cement used in class II cavities, in vivo.

The aim of this in vivo study was to evaluate the interfacial marginal adaptation of a calcium aluminate cement, Doxadent (DD), and to compare it intra-individually with a resin composite, Tetric Ceram/Syntac Single-Component (TC/SS), in Class II cavities. Sixteen Class II box-shaped, enamel-bordered cavities were prepared in eight premolars scheduled to be extracted after 1 month's service for orthodontic reasons. The interfacial marginal adaptation (internal surfaces) of the restorations was evaluated by a quantitative scanning electron microscope analysis using a replica method. DD showed a statistically significant, lower degree of gap-free adaptation to enamel compared with TC/SS: 84% vs. 93%. To dentin, DD showed a significantly better adaptation than TC/SS: 72% vs. 49%. A high frequency of enamel fractures perpendicular to the margins was observed for the DD restorations, which may be explained by an expansion of the calcium-aluminate cement. It can be concluded that DD showed a better adaptation to dentin while TC/SS showed a better adaptation to enamel. The dimensional changes of DD have to be investigated before clinical use can be recommended.

Surface roughness of a novel "ceramic restorative cement" after treatment with different polishing techniques in vitro.

The aim of this study was to determine the surface roughness of a novel calcium aluminate cement (CAC) intended for posterior restorations after treatment with different polishing devices in vitro. Forty-eight CAC specimens were polished with diamond burs at 15550 rpm or 27000 rpm, Sof-Lex discs, Jiffy points, Shofu silicone points, and Aaba universal polisher. Amalgam specimens were polished with Shofu silicone points and used as reference. Roughness was measured using a profilometer. The smoothest CAC surface was observed after use of the fine Sof-Lex disc (roughness average [Ra] 0.26 microm). Diamond burs at higher speed, points, and polisher gave rather similar results (Ra 0.58-0.72 microm). An increase in surface roughness could be seen from using diamond burs at lower speed (Ra 2.3 microm). Extra fine Shofu points and Sof-Lex discs as a final step reincreased surface roughness. Polished amalgam showed the smoothest surface in the study (Ra 0.17). It can be concluded that the smoothest CAC surfaces were obtained with the fine Sof-Lex discs. Different polishing points and diamond burs at higher speed, which are suitable polishing devices for posterior restorations, also gave relatively smooth surfaces.