Bulk-filled posterior resin restorations based on stress-decreasing resin technology: a randomized, controlled 6-year evaluation.

This randomized study evaluated a flowable resin composite bulk-fill technique in posterior restorations and compared it intraindividually with a conventional 2-mm resin composite layering technique over a 6-yr follow-up period. Thirty-eight pairs of Class II restorations and 15 pairs of Class I restorations were placed in 38 adults. In all cavities a single-step self-etch adhesive (Xeno V) was applied. In the first cavity of each pair, the flowable resin composite (SDR) was placed, in bulk increments of up to 4 mm. The occlusal part was completed with a layer of nanohybrid resin composite (Ceram X mono). In the second cavity of each pair, the hybrid resin composite was placed in 2-mm increments. The restorations were evaluated using slightly modified US Public Health Service (USPHS) criteria at baseline and then annually for a time period of 6 yr. After 6 yr, 72 Class II restorations and 26 Class I restorations could be evaluated. Six failed Class II molar restorations, three in each group, were observed, resulting in a success rate of 93.9% for all restorations and an annual failure rate (AFR) of 1.0% for both groups. The AFR for Class II and Class I restorations in both groups was 1.4% and 0%, respectively. The main reason for failure was resin composite fracture.

Eight-year randomized clinical evaluation of Class II nanohybrid resin composite restorations bonded with a one-step self-etch or a two-step etch-and-rinse adhesive.

OBJECTIVES: The aim of this study is to observe the durability of Class II nanohybrid resin composite restorations, placed with two different adhesive systems, in an 8-year follow-up. METHODS: Seventy-eight participants received at random at least two Class II restorations of the ormocer-based nanohybrid resin composite (Ceram X) bonded with either a one-step self-etch adhesive (Xeno III) or a control two-step etch-and-rinse adhesive (Excite). The 165 restorations were evaluated using slightly modified United States Public Health Services (USPHS) criteria at baseline and then yearly during 8 years. RESULTS: One hundred and fifty-eight restorations were evaluated after 8 years. Three participants with five restorations (three Xeno III, two Excite) were registered as dropouts. Twenty-one failed restorations (13.3%) were observed during the follow-up. Twelve in the one-step self-etch adhesive group (13.5%) and nine in the two-step etch-and-rinse group (13.0%). This resulted in nonsignificant different annual failure rates of 1.69 and 1.63%, respectively. Fracture of restoration was the main reason for failure. CONCLUSION: Good clinical performance was shown during the 8-year evaluation and no significant difference in overall clinical performance between the two adhesives. Fracture was the main reason for failure. CLINICAL RELEVANCE: The one-step self-etch adhesive showed a good long-term clinical effectiveness in combination with the nanohybrid resin composite in Class II restorations.

A randomized controlled clinical study of the effect of daily intake of Ascophyllum nodosum alga on calculus, plaque, and gingivitis.

OBJECTIVE: The aim of this study is to evaluate, in a randomized controlled cross-over study, the effect of daily intake of the alga Ascophyllum nodosum on supragingival calculus, plaque formation, and gingival health over a 6-month period. MATERIAL AND METHODS: Sixty-one adults with moderate to heavy calculus formation since their last yearly recall visit participated. In a randomized order over two 6-month periods, they swallowed two capsules daily, comprising a total of 500 mg dried marine alga powder (Ascophyllum nodosum, ProDen PlaqueOff®) or two negative control tablets. During the study, the participants maintained their regular oral habits. Their teeth were professionally cleaned at the start of each period and after the 6-month registrations. A wash out period of 1 month separated the two 6-month periods. Supragingival calculus (Volpe Manhold), gingivitis (Löe and Silness), gingival bleeding (Ainamo and Bay), and plaque (Quigley-Hein) were registered at screening and at the end of the two periods. Differences in oral health between the test and control periods were analyzed using a paired t test and Wilcoxon signed rank test. RESULTS: Fifty-five participants completed the study. After the alga intake, the mean calculus reduction was 52% compared to the control (p < 0.0001). Fifty-two participants showed less calculus formation in the alga group than in the control group. Plaque (p = 0.008) and gingival bleeding (p = 0.02) were also significantly less in the alga group. However, no significant difference was found between the groups for gingivitis (p = 0.13). CONCLUSIONS: The alga intake significantly reduced the formation of supragingival calculus and plaque and occurrence of gingival bleeding. The alga has a systemic effect on oral health. CLINICAL RELEVANCE: Daily intake of the alga Ascophyllum nodosum as an adjunct to customary oral hygiene showed a major reduction of supragingival calculus formation and reduced plaque formation. In addition, the calculus in the alga group was characterized by a more porous and less solid structure and was easier to remove than the calculus in the control group.

A randomized 10-year prospective follow-up of Class II nanohybrid and conventional hybrid resin composite restorations.

PURPOSE: To evaluate the 10-year durability of a nanohybrid resin composite in Class II restorations in a randomized controlled intraindividual comparison with its conventional hybrid resin composite predecessor. MATERIALS AND METHODS: Each of 52 participants received at least two Class II restorations that were as similar as possible. The cavities were chosen at random to be restored with a nanohybrid resin composite (Excite/Tetric EvoCeram (TEC); n=61) and a conventional hybrid (Excite/Tetric Ceram (TC); n=61). The restorations were evaluated with slightly modified USPHS criteria at baseline and then annually for 10 years. The overall performance of the experimental restorations was tested after intra-individual comparison and their ranking was tested using Friedman's two-way ANOVA. The level of significance was set at 5%. RESULTS: Four patient drop-outs with 8 restorations (4TEC, 4TC) were registered during the follow-up. A prediction of the caries risk showed that 16 of the evaluated 52 patients were considered as high risk patients. In total, 22 restorations, 11 TEC (3 premolars, 8 molars) and 11 TC (3 premolars, 8 molars) restorations failed during the 10 years. The main reason for failure was secondary caries (50%). 63% of the recurrent caries lesions were found in high caries risk participants. The overall success rate at 10 years was 80.7%, with an annual failure rate of 1.9%. No statistically significant difference was found in the overall survival rate between the two investigated resin composites. CONCLUSION: The nanohybrid and the conventional hybrid resin composite showed good clinical effectiveness in extensive Class II restorations during the 10-year study.

A prospective 8-year follow-up of posterior resin composite restorations in permanent teeth of children and adolescents in Public Dental Health Service: reasons for replacement.

OBJECTIVES: The aim of the study was to investigate reasons for replacement and repair of posterior resin composite (RC) restorations placed in permanent teeth of children and adolescents attending Public Dental Health Service in Denmark. MATERIAL AND METHOD: All posterior RC placed consecutively by 115 dentists over a period of 4 years were evaluated at baseline and up to 8 years later. The endpoint of each restoration was defined when repair or replacement was performed. The influence of patient, dentist and material factors on reasons for repair or replacement was investigated. RESULTS: A total of 4,355 restorations were placed. Replacements comprised 406 and repairs 125 restorations. The cumulative survival rate at 8 years was 84 %. Failed restorations were most frequently seen due to secondary caries (57 %), post-operative sensitivity (POS) (10 %) and RC fracture (6 %). POS was observed in 1.5 % of the evaluations and reported more often in girls and from teeth restored with a base material. Older dentists showed lower proportion of replaced restorations due to secondary caries than younger dentists. CONCLUSION: Posterior RC restorations in children and adolescents performed in general practice showed a good durability with annual failure rates of 2 %. The main reason for failure was secondary caries followed by post-operative sensitivity and resin composite fracture. A high proportion of replaced/repaired RC restorations were caused by primary caries in a non-filled surface. CLINICAL RELEVANCE: Secondary caries was the main reason for failure of RC in children and young adults. More teeth with post-operative sensitivity and a shorter longevity of restorations were observed when a base material was used.

Effect of essential oils containing and alcohol-free chlorhexidine mouthrinses on cariogenic micro-organisms in human saliva.

OBJECTIVE: The aim of this study was to evaluate the effect on mutans streptococci and lactobacilli in saliva of mouthrinsing with essential oils and an alcohol-free chlorhexidine. MATERIALS AND METHOD: Twenty healthy volunteers (mean age 59 years) participated in the double-blind randomized cross-over study. Three mouthrinses were used in 16 days rinsing periods in addition to their regular mechanical oral hygiene: a solution with essential oils (EO; Listerine), a solution with alcohol-free chlorhexidine (CHX; Paroex) and water (negative control). The mouthrinse periods were separated by 3-month washout periods. At days 0 (baseline) and 17 (end) of each mouthrinse period, paraffin stimulated whole saliva was collected in order to analyse CFU/ml saliva of mutans streptococci and lactobacilli. RESULTS: Only the CHX rinse showed a significant difference for CFU mutans streptococci between baseline and end (p = 0.004). The CFU mutans streptococci at the end of the rinse periods showed statistically significant differences between CHX vs EO (p = 0.039) and CHX vs water (p = 0.022). The difference in CFU lactobacilli between baseline and end was significant for CHX (p = 0.031), but not for the other rinses. No statistically significant differences for lactobacilli were found at the end of the rinse periods between the mouthrinses. CONCLUSION: A significant reduction in amount of cariogenic bacteria in saliva was observed after 16 days of alcohol-free chlorhexidine mouthrinse but not after the essential oils rinse. The high number of participant's not changing to a bacterial class with a reduced number of micro-organisms showed that both rinses had little clinical significance as a caries preventing treatment method, which can decrease the number of CFU cariogenic micro-organisms.

Clinical performance of a nanofilled resin composite with and without an intermediary layer of flowable composite: a 2-year evaluation.

The objective of this prospective clinical follow-up was to evaluate the 2-year clinical performance of a nanofilled resin composite in class II restorations. The restorations were made with and without intermediary layer of a nanofilled flowable resin composite studied in an intraindividual comparison. Each participant received at least two, as similar as possible, class II restorations of the nanofilled resin composite. One restoration of each pair (54) was chosen at random to be restored with an intermediary layer with flowable nanofilled resin composite. The other was restored without. The restorations were evaluated with slightly modified US Public Health Services criteria at baseline, 1, and 2 years. Ninety-two restorations, 46 pairs, were evaluated at 2 years. A prediction of the caries risk showed that 22 of the evaluated 48 patients were considered as high-risk patients. Two failures were observed, one in each group, resulting in a 2.2% failure rate. No statistical difference was seen between the restorations restored with and without layer of flowable resin composite. The nanofilled resin composite showed very good surface characteristics and color match, which did not change significantly during the follow-up period. The nanofilled resin composite showed a good clinical performance with a 2.2% failure rate after 2 years. No differences were observed between the restorations with and without the nanofilled flowable resin intermediary layer.

Fracture frequency and longevity of fractured resin composite, polyacid-modified resin composite, and resin-modified glass ionomer cement class IV restorations: an up to 14 years of follow-up.

The aim of this study was to evaluate the fracture frequency and longevity of fractured class IV resin composite (RC), polyacid-modified resin composite (compomer; PMRC), and resin-modified glass ionomer cement (RMGIC) restorations in a longitudinal long-term follow-up. Eighty-five class IV RC (43: Pekafil), PMRC (24: Dyract (D), Hytac (H)), and RMGIC (18: Fuji II LC (F), Photac Fil (P)) restorations were placed in ongoing longitudinal follow-ups in 45 patients (mean age 54.5 years). The restorations were evaluated during 14 years by slightly modified USPHS criteria at yearly recalls especially for their fracture behavior. For all restorations, 36.5% were fractured, with a Kaplan-Meier (KM) estimate of 8.8 years (standard error (SE) 0.5, confidence interval (CI) 7.9-9.8). The number of fractures per material was 11 RC (25.6%; KM 9.9 years, CI 8.7-11.0), 13 PMRC (54.2%; D 66.6%; H 50.0%; KM 7.5 years, CI 5.8-9.2), and seven RMGIC (36.5%; F 22.2%, P 71.4%; KM 6.9 years, CI 7.9-9.8). Significant differences were seen between RC and PMRC (p = 0.043). A significant higher fracture rate was observed in teeth 12 + 22 compared to teeth 11 + 21. No significant differences were observed between male and female patients. Restorations in bruxing patients (45) showed 22 fractures (KM 8 years; CI 6.9-9.3) and in non-bruxing patients (39) nine fractures (KM 9.9 years, CI 8.7-11.1; p = 0.017). With regard to the longevity of the replaced failed restorations, for RC, the mean age was 4.5 years; for PMRC, 4.3 years; and for RMGIC, 3.3 years. It can be concluded that fracture was the main reason for failure of class IV restorations. An improved longevity was observed for class IV restorations compared to those presented in earlier studies. RC restorations showed the lowest failure frequency and the highest longevity.

Effects of mouthrinses containing essential oils and alcohol-free chlorhexidine on human plaque acidogenicity.

The aim of this in vivo study was to evaluate the effect of two antimicrobial mouthrinses on dental plaque acidogenicity after a sucrose challenge. Twenty subjects, with a mean age of 59 years, participated in a double-blind intraindividual randomized study. Three mouthrinses were used in 16-day rinsing periods in addition to their regular mechanical oral hygiene: a solution with essential oils (EO), solution with alcohol-free chlorhexidine (CHX) and water (negative control). The three test periods were separated by 3-month washout periods. Changes in plaque acidogenicity were evaluated after a sucrose challenge at day 0 (baseline) and at day 17 of each mouthrinse period using the microtouch method. Both CHX and EO resulted at day 17 in statistically significant less attenuated pH falls compared to the water rinse. The CHX mouthrinse resulted in the least pronounced pH values compared with EO (ns) during the whole 30-min period. When calculated as area under the curve (AUC), significantly lower values (AUC(6.2) ) were found for CHX and EO at day 17 compared to day 0. A significant difference for AUC(6.2) between CHX and water was found at day 17. No statistically significant differences were found for any of the comparisons with AUC(5.7). The results from this study indicate that both the essential oils and the alcohol-free chlorhexidine reduced plaque acidogenicity after a sucrose challenge. Large interindividual variations were observed.

Awareness of toothbrushing and dentifrice habits in regularly dental care receiving adults.

The aim of this study was to investigate toothbrushing and dentifrice habits in a Swedish adult population with relatively high caries frequency, which received regularly dental care and to evaluate the awareness of their toothbrush technique. Sixty adult participants with high caries frequency, 29 woman and 31 men, answered a self-reporting questionnaire with 42 questions concerning their oral care, brushing technique and -habits.The responses were related to their clinical behaviour observed during a customary toothbrushing session. Fifty-three participants fulfilled both the questionnaire and the clinical observation. Half of these used toothpaste containing 1450-1500 ppm fluoride but only one of all participants was aware of the fluoride concentration used. The majority used a manual toothbrush and 95% brushed their teeth twice a day using 0.9 g toothpaste. A wide range of brushing methods and habits was observed. Sixty percent did not brush systematically. Spitting of toothpaste-saliva during brushing was performed by 60% and after brushing by 15%.The observed brushing times were significantly higher than the self reported. The observed brushing times were <1 min: 3.4%, 1-2 min: 36.7% and >2 min: 47.0%. There was a significant correlation between observed brushing time and caries activity. Rinsing with water after brushing was performed once (32%) or twice (44%) during the observations. Only 9% rinsed with toothpaste slurry after brushing. It can be concluded that the awareness of the individual toothbrushing, post-brushing behaviour and the use of fluoride toothpaste was non-optimal in the adult participants. Oral health promotion by optimalized use of fluoride toothpaste and improved post-brushing behaviour should be recommended.

Clinical effectiveness of a low-shrinkage resin composite: a five-year evaluation.

PURPOSE: To study the durability of a recently developed low-shrinkage resin composite, suggested to counter the stress formation in direct resin composite restorations. MATERIALS AND METHODS: Each of 50 patients received one or two pair(s) of Class II restorations. The first restoration in the pair was a low-shrinkage resin composite (InTen-S) and the second a hybrid resin composite restoration (Point 4). Both restorations were placed with an etch-and-rinse bonding system and an oblique layering technique. A total of 106 restorations, 33 premolar and 73 molars, were placed. The restorations were evaluated annually. RESULTS: At 5 years, 97 restorations were evaluated. Two participants reported slight postoperative sensitivity symptoms for a few weeks after placement. Twelve non acceptable restorations were observed during the 5 years, five InTen-S (10.4%) and 7 Point 4 (14.3%) (not significant). Secondary caries was the main reason for failure (8) followed by composite fracture (2) and tooth fracture (2). CONCLUSION: The low-shrinkage resin composite showed good durability, but not significantly better than the control resin composite in Class II cavities. Most failures occurred at the last part of the study. Secondary caries was the main reason for failure.

A randomized controlled evaluation of posterior resin restorations of an altered resin modified glass-ionomer cement with claimed bioactivity.

OBJECTIVE: The objective of this randomized controlled prospective clinical trial was to evaluate the short time clinical behaviour of an altered resin modified glass-ionomer cement (RMGIC), which is claimed to possess bioactivity, in posterior restorations and to compare it intraindividually with a nanofilled resin composite. METHODS: Totally 78 pairs Class II and 4 pairs Class I restorations were placed in 29 female and 38 male participants with a mean age of 58.3 years (range 37-86). Each patient received at random at least one pair of, as similar as possible, Class II or Class I restorations. In the first cavity of each pair, the modified flowable RMGIC (ACTIVA Bioactive; AB) was placed after phosphoric acid etching of the cavity and without adhesive, according to the instructions of the manufacturer. In the other cavity a well established nanofilled resin composite (CeramX; RC) with a single step self-etch adhesive (Xeno Select) was placed. The restorations were evaluated using slightly modified USPHS criteria at baseline, 6 and 12 months. Caries risk and parafunctional habits of the participants were estimated. RESULTS: 158 restorations, 8 Class I and 150 Class II, were evaluated at the one year recalls. At baseline two failed restorations were observed (2AB), at 6 months six failures (5AB, 1RC) and at 12 months another thirteen failed restorations were observed (12AB, 1RC). This resulted in annual failure rates of 24.1% for the AB and 2.5% for RC (p<0.0001). The main reasons for failure for AB were lost restorations (5), postoperative symptoms (4) and secondary caries (3). Do to the unacceptable very high one-year failure frequency, the clinical study was stopped and no further evaluation will be performed. SIGNIFICANCE: The use of the AB restorative in Class II cavities, applied as instructed by the manufacturer after a short phosphoric acid pretreatment but without adhesive system, resulted in a non-acceptable very high failure frequency after a one year period. Further studies should be conducted using a bonding agent.

Long-term dentin retention of etch-and-rinse and self-etch adhesives and a resin-modified glass ionomer cement in non-carious cervical lesions.

OBJECTIVES: The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems. METHODS: A total of 270 Class V restorations of four etch-and-rinse, one self-etch adhesive system and a resin-modified glass ionomer cement were placed in non-carious cervical lesions without intentional enamel involvement. The restorations were evaluated at baseline, 6, 12, 18, and 24 months and then every year during a 13-year follow-up. Dentin bonding efficiency was determined by the percentage of lost restorations. RESULTS: During the 13 years, 215 restorations could be evaluated. The cumulative loss rate at 13 years was 53.0%, with significant different failures rates for the different systems varying between 35.6 and 86.8%. Four systems fulfilled the ADA 18-month full acceptance retention criteria. Two systems showed at 18 months and earlier high debonding rates. The annual failure rates for the etch-and-rinse systems were Optibond 3.1%, Permagen 13.0%, Scotchbond MP 4.8%, Syntac classic 2.8%; for the self-etch system P&S 4.4%; and the resin-modified glass ionomer cement Vitremer 2.7%. CONCLUSION: It can be concluded that all systems showed a continuous degradation of the bond with a wide variation, which was independent of the adhesion strategy. Three bonding systems showed a cumulative failure rate after 13 years between 36 and 41% with the best retention for the resin-modified glass ionomer cement and a four-step etch-and-rinse system.

Clinical long-term retention of etch-and-rinse and self-etch adhesive systems in non-carious cervical lesions. A 13 years evaluation.

OBJECTIVES: The aim of this study was to evaluate the clinical long-term retention to dentin of seven adhesive systems. METHODS: A total of 337 Class V restorations of three three-step etch-and-rinse, one two-step etch-and-rinse and three self-etch adhesive systems were placed in non-carious cervical lesions without intentional enamel involvement. The restorations were evaluated at baseline and then every 6 months during a 13 years follow-up. Dentin bonding efficiency was determined by the percentage of lost restorations. RESULTS: During the 13 years, 275 restorations could be evaluated. The cumulative loss rate at 13 years was 60.3%, with significant different failures rates for the different systems varying between 26.3 and 94.7%. Three materials fulfilled the ADA 18 months full acceptance criteria. Three systems showed already at 18 months or earlier catastrophical debonding rates. The annual failure rates for the three-step etch-and-rinse systems were: Allbond 2 4.1%, Clearfil LB 2.0% and Denthesive 7.3%. For the two-step etch-and-rinse Gluma 2000 6.5%, and for the self-etch systems ART 3.2%, Denthesive 2 5.7% and PUB 3 4.5% CONCLUSION: A continuous degradation of the resin-dentin bond was observed for all bonding systems during the follow-up expressed by the increasing loss rates. A wide variation of dentin bonding effectiveness was seen between the systems independent to adhesion strategy.

Nine-year evaluation of a polyacid-modified resin composite/resin composite open sandwich technique in Class II cavities.

OBJECTIVES: The aim of this study was to evaluate in an intraindividual comparison the durability of a polyacid-modified resin composite/resin composite open sandwich restoration in a 9 years follow-up. A polyacid-modified resin composite (PMRC; compomer, Dyract) was placed as an intermediate layer and covered with resin composite (RC, Prisma TPH). A direct RC restoration was used as control. METHODS: Each of 57 patients, received at least one pair of Class II restorations, one open sandwich and one resin composite control. In total 75 pairs of Class II restorations, 68 premolars and 82 molars, all in occlusion, were placed by two dentists. Most of the cavities were surrounded by enamel. The restorations were evaluated at baseline, 6, 12, 24, 36 months and 9 years by slightly modified USPHS criteria. Survival of restorations grouped on the two different techniques was determined using Kaplan-Meier survival curves. RESULTS: After 9 years, 14 of 135 evaluated restorations were estimated as unacceptable, 6 in the sandwich group and 8 in the control group. Over all annual failure rate during the 9-year period was 1.1%. The survival rate was not significant different between the two techniques (p=0.604). Reasons of failure were: secondary caries (8), fracture of tooth (1), fracture of restoration (2), endodontic treatment (3). CONCLUSIONS: Both restorative techniques showed good durability during the 9-year period. No clinical advantage was observed for the sandwich technique.

Clinical bonding of a single-step self-etching adhesive in noncarious cervical lesions.

PURPOSE: The aim of this study was to evaluate the clinical retention to dentin of a single-step self-etching adhesive system. MATERIALS AND METHODS: A total of 133 Class V restorations were placed with the self-etching primer Xeno III and a resin composite (Tetric Ceram) or a polyacid-modified resin composite (Dyract AP) in noncarious cervical lesions without intentional enamel involvement. The restorations were evaluated at baseline and then every 6 months during a 2-year follow-up. Dentin bonding efficacy was determined by the percentage of lost restorations. RESULTS: During the 2 years, 130 restorations could be evaluated. The cumulative loss rate at 2 years was 7.7%, with no significant differences between the two restorative materials. The self-etching adhesive fulfilled the 18-month full acceptance ADA criteria. CONCLUSION: The single-step self-etching adhesive showed acceptable clinical retention rates to dentin surfaces during the evaluation period independent of restorative material used.

Ozone air levels adjacent to a dental ozone gas delivery system.

OBJECTIVE: Ozone (O3) has been suggested as an anti-microbial treatment in dentistry, with an ozone gas delivery system introduced for the treatment of fissure and root caries. The aim of this study was to investigate the sealing capacity of the novel delivery system and its re-suction capacity during accidental displacement of the cup at different stages of ozone delivery. MATERIAL AND METHODS: Ozone leakage was studied in vitro after application on a flat metal surface and on buccal and occlusal tooth surfaces. An ozone analyzer was used to measure ozone gas concentrations adjacent to the delivering cups when adapted to the target surfaces during and after 10-20 s application cycles. The measured levels were compared with the background concentrations in the room. Measurements were performed 1) after complete ozone application cycles, 2) within the cycle before the start of the suction period, and 3) after displacements of the cup during the cycles. RESULTS: Ozone air values varied between 8 and 166 microgram/meter-3 for the flat metal surface and between 0 and 108 microgram/meter-3 for the tooth surfaces. Ozone leakage levels were 7.6 microgram/m-3 for the flat and and 7.4 microgram/meter-3 and 5.6 microgram/meter-3 for the buccal and occlusal surfaces, respectively, and 5.2 microgram/meter-3 and 9.8 microgram/meter-3 for the premolar and molar surfaces, respectively. Cycles with displacement showed significantly higher leakage levels than continuous complete cycles (p=0.03). CONCLUSIONS: Ozone application cycles with displacements showed significantly higher leakage levels than continuous complete cycles. The largest ozone delivery cups showed the highest leakage values. A change in background levels was seen with similar change in adjacent ozone levels. The overall measured ozone leakage values were low after normally functioning delivery cycles and after repeated displacements. The delivery system can be considered safe.

Durability of a low shrinkage TEGDMA/HEMA-free resin composite system in Class II restorations. A 6-year follow up.

OBJECTIVE: The objective of this randomized controlled prospective trial was to evaluate the durability of a low shrinkage and TEGDMA/HEMA-free resin composite system in posterior restorations in a 6-year follow up. METHODS: 139 Class II restorations were placed in 67 patients with a mean age of 53 years (range 29-82). Each participant received at random two, as similar as possible, Class II restorations. In the first cavity of each pair the TEGDMA/HEMA-free resin composite system was placed with its 3-step etch-and-rinse adhesive (cmf-els). In the second cavity a 1-step HEMA-free self-etch adhesive was used (AdheSe One F). The restorations were evaluated using slightly modified USPHS criteria at baseline and then yearly during 6 years. Caries risk and parafunctional habits of the participants were estimated. RESULTS: Three molar teeth showed mild post-operative sensitivity during 3 weeks for temperature changes and occlusal forces. After 6 years, 134 Class II restorations were evaluated. Twenty-one restorations, 8 cmf-els (11.4%) and 13 ASE-els (20%) failed during the 6 years (p<0.0001). The annual failure rates were 1.9% and 3.3%, respectively. The main reasons for failure were fracture followed by recurrent caries. Most fractures and all caries lesions were found in high risk participants. SIGNIFICANCE: The Class II resin composite restorations performed with the new TEGDMA/HEMA-free low shrinkage resin composite system showed good durability over six years.

Dimensional change of a calcium aluminate cement for posterior restorations in aqueous and dry media.

OBJECTIVES: A calcium aluminate cement has recently been developed, with claims of being an alternative to dental amalgam and resin composites in posterior cavities. However, its' mechanical properties are not well evaluated and the aim of the study was therefore, to evaluate its' dimensional stability over time. METHODS: The dimensional changes of the cement, Doxadent, and two composite resins, Esthet-X and InTen-S, were tested during 360 d. The specimens were stored at 37+/-1 degrees C either in 100% air humidity (dry) or immersed in distilled water (wet), except for the first 24h when all specimens were stored at 100% air humidity and 37+/-1 degrees C. RESULTS: During the first 24h, Doxadent decreased in volume with 0.04%, while InTen-S and Esthet-X decreased with 1.60 and 1.75%, respectively. From d 1-360, the dry Doxadent specimens increased in volume with 2.0% and in weight with 5.5%, while the corresponding increase for the wet specimens were 4.1 and 6.3%, respectively. The volume of both composites increased 0.8% or less in dry and wet conditions, while the increase in weight for InTen-S was 1.2% for the wet specimens and 0.6% for the dry. The corresponding figures for Esthet-X were 0.7 and 0.2%. SIGNIFICANCE: Doxadent was less dimensionally stable than the composites tested. Doxadent increased 2 times more in volume immersed in water than in 100% air humidity, while the increase in weight was almost similar. The clinical implications of the results found in the present study are uncertain. A material that continues to absorb water during prolonged periods and continues to react is questionable for clinical use.

Fiber-reinforced packable resin composites in Class II cavities.

OBJECTIVE: To evaluate the 6-year performance of two glass fiber-reinforced packable resin composites in Class II cavities. METHODS: Sixty-three participants received 87 medium to large, cervically dentin bordered, Class II restorations of two fiber-reinforced resin composites, 42 Nulite F (N) and 45 Alert (A). The restorations were evaluated clinically, according to slightly modified USPHS criteria at baseline, after 6 months, and yearly during 6 years. RESULTS: At 2 years the cumulative failure frequencies for N and A were 4.8% and 2.2%, respectively, which increased at 6 years to 25.0% and 12.8%. Reasons for failure were secondary caries, material and cusp fracture. The majority of the failures occurred after 3 years. Secondary caries occurred between 4 and 6 years. The incorporation of fibers resulted in very rough surface characteristics. CONCLUSIONS: A rather high failure rate was observed for one of the fiber-reinforced resin composites, while the other fulfilled the ADA criteria. The occurrence of most failures after 3 years indicated the necessity of long-term evaluations of new materials.