Light curing of resin-based composites in the LED era  

 

Norbert  Krämer, dmd, phd,  Ulrich  Lohbauer, dipl eng, msc , phd,  Franklin  García-Godoy, dds , ms, &  Roland  Frankenberger, dmd, phd  

 

Abstract: This review thoroughly accumulated information regarding new technologies for state-of-the-art light curing of resin composite materials. Visible light cured resin-based composites allow the dentist to navigate the initiation of the polymerization step for each layer being applied. Curing technology was regularly subjected to changes during the last decades, but meanwhile the LED era is fully established. Today, four main polymerization types are available, i.e. halogen bulbs, plasma arc lamps, argon ion lasers, and light emitting diodes. Additionally, different curing protocols should help to improve photopolymerization in terms of less stress being generated. Conclusions were: (1) with high-power LED units of the latest generation, curing time of 2 mm thick increments of resin composite can be reduced to 20 seconds to obtain durable results; (2) curing depth is fundamentally dependent on the distance of the resin composite to the light source, but only decisive when exceeding 6 mm; (3) polymerization kinetics can be modified for better marginal adaptation by softstart polymerization; however, in the majority of cavities this may not be the case; (4) adhesives should be light-cured separately for at least 10 seconds when resin composite is applied directly; (5) photocuring through indirect restorations such as ceramics is still a problem, therefore, both dual-cured adhesives and dual-cured composites and resin coating in any way are recommended; and (6) heat generation with high-power photopolymerization units should not be underestimated as a biological problem for both gingival and pulpal tissues. (Am J Dent 2008;21:135-142).  

 

*: Prof. Dr. Roland Frankenberger, Dental Clinic 1, Operative Dentistry and Periodontology, University Medical Center Erlangen, University of Erlangen-Nuremberg, Glückstraße 11, D-91054 Erlangen, Germany.  

E-*: frankbg@dent.uni-erlangen.de

 

 

Long-term bond strengths to dentin treated with different re-wetting solutions  

 

Ricardo  Walter, dds , ms ,  Patricia  A.  Miguez, dds , ms ,  Edward J. Swift Jr., dds , ms &  Patricia  N. R.  Pereira, dds , phd  

 

Abstract: Purpose: To evaluate the microtensile bond strengths (µTBS) of two etch-and-rinse one-bottle adhesive systems to air-dried dentin re-wet with different agents. Methods: 48 bovine teeth were ground flat to 600-grit and were assigned for treatment with either Single Bond or One-Step adhesives. Each group had three subgroups of re-wetting agents: water, Gluma Desensitizer and Aqua-Prep F. The teeth were acid-etched, air-dried for 5 seconds and re-wet with water, Gluma Desensitizer or Aqua-Prep F for 30 seconds and blot dried. Control specimens were prepared using a moist bonding technique. The adhesives were applied and the teeth were restored with Filtek Z250 or Renew composite. After 24 hours in distilled water at 37ºC, the teeth were sectioned into 0.7 mm-thick slabs, trimmed, and immediately tested for µTBS or stored for 6 months or 1 year prior to testing. Fracture sites were examined under scanning electron microscope ( SEM ). Data were evaluated by one- and three-way ANOVA, and Fisher’s PLSD test (P< 0.05). Results: Except for Aqua-Prep F, the µTBS in the control, water and Gluma Desensitizer subgroups did not change significantly after 1-year for both Single Bond and One-Step groups. SEM analysis showed no specific pattern of fracture in the Single Bond specimens. One-Step had the majority of the fractures at the interface at baseline, and becoming a mixture of fractures at the interface and within the adhesive resin after 1 year. (Am J Dent 2008;21:143-147).

   

*: Dr. Ricardo Walter, Department of Operative Dentistry, CB #7450, The University of North Carolina at Chapel Hill, Chapel Hill , NC 27599-7450 , USA . E-*: rick_walter@dentistry.unc.edu

 

 

 

36-month clinical evaluation of two adhesives and microhybrid

resin composites in Class I restorations

 

Edward  J.  Swift, Jr., dmd , ms ,  André  V.  Ritter, dds , ms ,  Harald  O.  Heymann, dds , med ,

John  R.  Sturdevant, dds  &  Aldridge  D.  Wilder, Jr., dds

 

Abstract: Purpose: To compare the clinical performance of a self-etching adhesive with that of a popular etch-and-rinse adhesive in Class I posterior composite restorations. Methods: 60 Class I resin composite restorations (30 per group) were placed in matched pairs using either the self-etch adhesive Xeno III and the microhybrid resin composite Esthet-X or the etch-and-rinse adhesive OptiBond Solo Plus and Point 4 microhybrid resin composite. Subjects were interviewed via telephone 1 week after restoration placement to assess early post-operative sensitivity. In addition, the restorations were evaluated clinically for post-operative sensitivity, marginal quality, wear, and other characteristics immediately after placement and at 6, 12, 18, and 36 months from baseline. Results: During the first week after placement, subjects reported that 23% of restorations in each group had post-operative sensitivity. Sensitivity decreased greatly with time, and differences between the two groups were never statistically significant. Marginal integrity and discoloration were similar for each group at each recall evaluation. Wear of both resin composites increased over time, but mean wear remained at less than 100 µm for each resin composite at 3 years. (Am J Dent 2008;21:148-152).

 

 

*: Dr. Edward J. Swift, Jr., Department of Operative Dentistry, University of North Carolina, 433 Brauer Hall, CB#7450, Chapel Hill, NC, 27599-7450, USA. E-*: ed_swift@dentistry.unc.edu

 

 

Effectiveness of indirect composite resin silanization evaluated

by microtensile bond strength test

 

Mauro Itaru Honda, dds ,  Flávia  Martão  Flório, dds , ms, scd  &  Roberta Tarkany Basting, dds , ms, scd, phd

 

Abstract: Purpose: To assess the effectiveness of using silane before cementing laboratory resins, by means of microtensile bond strength test. Methods: 40 human molars were selected, cleaned and stored in a 0.1% thymol solution. The occlusal surfaces of these teeth were removed and flattened until dentin was exposed. Next, the laboratory resin blocks were cemented (Adoro or Artglass) with Single Bond and Rely X adhesive cementing systems, by the same cementing protocol, the only difference between the groups being whether or not silane was applied. The teeth to which the blocks were cemented were prepared to obtain stick-shaped test specimens with an approximate area of 1.00 mm² (± 0.12 mm²) for the microtensile bond strength tests. Afterwards, under x2.5 magnification, the fracture modes were visually classified as adhesive, cohesive or mixed. Results: ANOVA (P≤ 0.05) showed that there were significant differences in the microtensile values between the indirect composites studied. The highest microtensile bond strength values were found with the Artglass (58.08 MPa without silane, 49.76 MPa with silane), and lowest values with Adoro (37.08 MPa without silane, 39.52 MPa with silane). There were no differences in the microtensile bond strength values, with or without silane application. The fractures were considered predominantly adhesive in 68.3%, mixed in 25.8% and cohesive in 5.9% of cases. The use of silane did not contribute significantly to increasing microtensile bond strength during laboratory resin cementation. (Am J Dent 2008;21:153-158).

 

 

*: Prof. Dr. Roberta Tarkany Basting, Faculty of Dentistry and São Leopoldo Mandic Dental Research Center, Department of Restorative Dentistry – Operative, Rua José Rocha Junqueira, 13, Bairro Swift, Campinas – SP, CEP: 13045-755, Brazil.  E-*: rbasting@yahoo.com

 

 

 

Effect of blood contamination on the shear bond strength at resin/dentin interface in primary teeth

 

Maria Stella Raffaini, dds , Jaciara Miranda Gomes-Silva, dds Carolina Paes Torres-Mantovani, dds , msc , Regina Guenka Palma-Dibb, dds , ms, phd  &  Maria Cristina Borsatto, dds , ms, phd

 

Abstract: Purpose: To assess in vitro the shear bond strength at the resin/dentin interface in primary teeth after contamination with fresh human blood. Methods: 75 crowns of primary molars were embedded in acrylic resin and mechanically ground to expose a flat dentin surface. The specimens were randomly assigned to five groups (n=15), according to the surface treatment. Group 1 (control) had no blood contamination. The other groups were blood-contaminated and subjected to different post-contamination protocols: in Group 2, the surfaces were rinsed with water; in Group 3, the surfaces were air-dried; in Group 4, the surfaces were rinsed and air-dried; and in Group 5, no post-contamination treatment was done. In all groups, a 3-mm dentin bonding site was demarcated, Single Bond adhesive system was applied and resin composite cylinders were bonded. After 24 hours in distilled water, shear bond strength was tested at a crosshead speed of 0.5 mm/minute. Results: Means (in MPa) were: Group 1: 7.1 (± 4.2); Group 2: 4.0 (± 1.8); Group 3: 0.9 (± 0.7); Group 4: 3.9 (± 2.2) and Group 5: 1.3 (± 1.5). Data were analyzed statistically by the Kruskal-Wallis test at 5% significance level. Groups 2 and 4 were similar to each other (P> 0.05) and both ware similar to Group 1 (P > 0.05). These groups (2, 3 and 4) had statistically significantly higher bond strengths than Groups 3 and 5 (P < 0.05). Blood contamination negatively affected the shear bond strength to primary tooth dentin. Among the blood-contaminated groups, water-rinsed specimens had higher bond strengths than those that were exclusively air-dried or not submitted to any post-contamination protocol before adhesive application. (Am J Dent 2008;21:159-162).

   

 *: Dr. Maria Stella Raffaini, Avenida Caramuru, 630, Bloco 2, apto 204 CEP: 14030-000 Ribeirão Preto, SP, Brazil. E-*: msggr@forp.usp.br

 

 

Fracture resistance of Class II glass-ionomer cement restorations

 

Terezinha  Jesus  Esteves  Barata, phd,  Eduardo  Bresciani, phd,  Ticiane  Cestari  Fagundes, msc , Daniela Francisca Gigo Cefaly, phd, José Roberto Pereira Lauris, phd  &  Maria Fidela Lima Navarro, phd

 

Abstract: Purpose: To investigate in vitro the effect of retentive grooves, GIC type and insertion method on the fracture resistance of Class II glass-ionomer cement (GIC) restorations. Methods: Premolars were divided into 12 groups (n=10) according to three variables: retentive grooves [presence (PR) or absence AR)], GICs type [Ketac-Molar (KM), Fuji VIII (F8) and RelyX Luting (RX)], and insertion method [syringe injector (SI) or spoon excavator (SE)]. The specimens were subjected to fracture resistance test. Data were submitted to three-way ANOVA and multiple comparisons were performed using a Tukey test (P< 0.05). Results: Mean fracture resistance values (Kgf) ± standard deviations (SD) were: KM (PR+SI) = 65.66 ± 2.5; KM (PR+SE) = 62.58 ± 2.1; KM (AR+SI) = 57.11 ± 1.9; KM (AR+SE) = 51.94 ± 2.3; F8 (PR+SI) = 63.05 ± 2.1; F8 (PR+SE) = 60.12 ± 2.3; F8 (AR+SI) = 55.11 ± 1.9; F8(AR+SE)=49.20±1.6; RX (PR+SI)=50.99±2.4; RX (PR+SE)=48.81±2.5; RX (AR+SI)=45.53±2.6; RX (AR+SE)=41.88 ± 3.0. Statistically significant differences were observed among all the groups tested (P= 0.001). There was significant difference when pooled means for GIC type were compared with retentive grooves (P= 0.01) and when pooled means for retentive grooves were compared with insertion method (P= 0.01). (Am J Dent 2008;21:163-167).

 

 

*: Dr. Maria Fidela Lima Navarro, Bauru School of Dentistry, University of São Paulo, Alameda Dr. Octávio Pinheiro Brisolla 9-75, Bauru-SP 17012-901, Brazil.  E-*: mflnavar@usp.br

 

 

Tetracycline gel as an adjunct to surgical root debridement

 

Antonio Wilson Sallum, dds, ms, phd,  Renato Vasconcelos Alves, dds, ms, phd,

Lúcio Flávio Teixeira Damis, dds, ms, phd,   Patricia Fernanda Roesler Bertolini, dds, ms, phd, Francisco Humberto Nociti Junior, dds, ms, phd  &   Enilson Antonio Sallum, dds , ms, phd

 

Abstract: Purpose: To evaluate the influence of tetracycline gel, brushed on tooth surfaces, on periodontal clinical parameters following root debridement. Methods: 20 subjects diagnosed with chronic periodontitis and presenting a minimum of two proximal sites on anterior teeth (maxillary or mandibular) with probing depth ± 5 mm, were selected. Following oral hygiene instructions and ultrasonic supragingival instrumentation, subjects were assigned to one of the following groups: RDS – root debridement with Gracey curettes and root brushing with saline solution; and RDT – root debridement with Gracey curettes and root brushing with 40% tetracycline gel. Full-thickness flaps were reflected and instrumentation was performed using a clinical microscope to optimize calculus detection. Probing depth (PD), relative gingival margin level (RGML) and relative attachment level ( RAL ) measures were registered at five visits: baseline and days 30, 60, 90 and 120 postoperative. Results: Both approaches were able to markedly reduce the PD values from baseline in all periods (P< 0.0001). No differences were found for RAL values in any of the groups. No differences were found between groups. In conclusion, the application of tetracycline gel does not seem to provide any additional improvement on clinical periodontal parameters after root debridement. (Am J Dent 2008;21:168-170).

 

 

*: Dr. Antonio Wilson Sallum, Division of Prosthodontics and Periodontics, School of Dentistry at Piracicaba, Av Limeira 901, Areião, Piracicaba  CEP 13414-903, São Paulo, Brazil.  

E-*: periodontia@fop.unicamp.br

 

 

Subgingival triclosan-polydimethylsiloxane gel as an adjunct to scaling

and root planing

 

Giovana Lecio, dds ,   Luciana M. Shaddox,  dds , ms, phd,   Marcelo Diniz Carvalho, dds , ms,

Poliana Mendes Duarte, dds , ms, phd,   Roberto Santos Tunes, dds ,  Getulio Rocha Nogueira-Filho, dds , ms, phd  &  Enilson Antonio Sallum, dds , ms, phd

 

Abstract: Purpose: To evaluate the influence of a triclosan-polydimethylsiloxane-containing gel when used as an adjunct to scaling and root planing on the treatment of chronic periodontal disease. Methods: A 3-month, double-blind, randomized parallel design clinical trial was performed in 20 subjects with chronic periodontitis. The subjects, presenting at least three anterior sites with probing depth (PD) ± 5 mm and bleeding on probing (BoP), were randomly assigned to two experimental groups: Group SRP -T: scaling/root planing plus test gel application (triclosan 1% + polydimethylsiloxane 13%) or Group SRP : scaling/root planing plus control gel application (polydimethylsiloxane 13%). Immediately following mechanical therapy, each assigned gel was applied to the selected sites and once a week during the following 3 weeks. Re-examinations were carried out on days 45 and 90 after the last irrigation. Results: Significant reductions in PD and clinical attachment level ( CAL ) were observed for both groups in both periods (P< 0.05). However, SRP -T showed lower means of PD than SRP at Day 45 (3.60 ± 0.87 versus 4.77 ± 1.38, respectively, P= 0.035) and CAL at both 45 days (4.63 ± 1.17 versus 6.07 ± 1.43, P= 0.023) and 90 days (4.45 ± 1.19 versus 5.91 ± 1.37, P= 0.021). No differences were found for bleeding on probing, plaque index and gingival recession (P> 0.05) between groups. (Am J Dent 2008;21:171-174).

   

   

*: Dr. Luciana M. Shaddox, Department of Periodontology, School of Dentistry , Rm. D10-6B, University of Florida , 1600 Archer Road, P.O. Box 100434 , Gainesville , FL   32610 , USA . E-*: lshaddox@dental.ufl.edu

 

 

 

Removal time of fiber posts versus titanium posts

 

Robert Q. Frazer, dds, Robert  E.  Kovarik, dmd, ms, Kenneth  B.  Chance, dds, ms  &  Richard J. Mitchell, phd

 

Abstract: Purpose: To evaluate the time needed to remove a glass reinforced fiber post versus a titanium post. Methods: 40 extracted anterior teeth were mounted in acrylic blocks then treated endodontically. They were randomly assigned to three groups. The teeth were sectioned horizontally, with the coronal portion removed. The fiber posts were cemented with resin cement and the titanium posts were cemented with glass ionomer or resin cement. The fiber posts were removed by coring them out internally. The titanium posts were removed by creating a trough around the post then vibrating with ultrasonic energy. The teeth were examined visually and radiographically to ensure complete removal of the post and cement. Removal time included the time to make radiographs necessary to ensure complete removal. Results: Post-cement combination significantly affected the median rank of the removal time (Kruskal-Wallis test; H= 12.709; P= 0.002). The mean rank removal time of titanium posts cemented with resin cement were significantly higher than the mean rank of the other two post-cement combinations (Dunn’s multiple comparison test; P< 0.05). There was no significant difference between the other two combinations. (Am J Dent 2008;21:175-178).

 

 

*: Dr. Robert Q. Frazer, Department of Prosthodontics, University of Kentucky College of Dentistry, Room D-640, Chandler Medical Center, Lexington, KY 40539-0297, USA.  E-*: rfrazer@uky.edu

 

 

Placement of fiber prefabricated or custom made posts affects the 3-year survival of endodontically treated premolars

 

Maria Crysanti Cagidiaco, md, dds, phd,   Franklin García-Godoy, dds, ms, Alessandro Vichi, dds, phd,  Simone Grandini, dds, ms, phd,  Cecilia Goracci, dds, ms, phd  &  Marco Ferrari, md, dds, phd

 

Abstract: Purpose: To assess whether the amount of residual coronal dentin and the placement of a prefabricated (DT Light Post)(LP) or a customized fiber post (Ever Stick Post)(ES) have a significant influence on the 3-year survival of endodontically treated premolars. Methods: A sample of 345 patients provided six groups of 60 premolars in need of endodontic treatment. Groups were defined based on the amount of dentin left at the coronal level after endodontic treatment and before abutment build-up. Within each group teeth were randomly divided into three subgroups (n=20). In Subgroup A, no root canal retention was provided for the coronal restoration. In Subgroups B and C, LP and ES, respectively, were placed inside the root canal. All the teeth were finally restored with a single unit metal-ceramic crown. Results: Data were not affected by any loss to follow-up. The overall 36-month survival rate of crowned endodontically treated premolars was 76.7%. The lowest survival rate was recorded for teeth restored without any root canal retention (62.5%). Teeth restored with LP had a survival rate higher (90.9%) than those restored with ES (76.7%). The Cox regression analysis showed that the presence of root canal retention was a significant factor for survival (P< 0.05). The decrease in failure risk was higher in teeth restored with LP (HR= 0.1; 95% CI for HR= 0.09 to 0.34; P< 0.001) than when using ES (HR= 0.5; 95% CI for HR= 0.3 to 0.7; P= 0.003). Teeth retaining one (HR= 0.3; 95% CI for HR= 0.2 to 0.7; P= 0.003), two (HR= 0.2; 95% CI for HR= 0.1 to 0.5; P< 0.001), or three coronal walls (HR= 0.1; 95% CI for HR= 0.05 to 0.3; P< 0.001) had a significantly lower failure risk than teeth deprived even of the ferrule effect. Similar failure risks existed for teeth missing all the coronal walls regardless of the presence or absence of a ferrule effect (P> 0.05). Interaction terms were not significant (P> 0.05). Post placement and the amount of residual coronal dentin affected the 3-year survival of endodontically treated premolars. (Am J Dent 2008;21:179-184).

 

 

*: Prof. Dr. Marco Ferrari, Department of Oral Sciences, Policlinico Le Scotte, Viale Bracci, Siena 53100, Italy.  E-*: m.ferrari@mclink.it

 

 

Plaque removal efficacy of an advanced rotation-oscillation

power toothbrush versus a new sonic toothbrush

 

Aaron  R.  Biesbrock, dmd, phd, ms,  Patricia  A.  Walters, rdh, msdh, msob,  Robert  D. Bartizek , ms , C.   Ram  Goyal, dds   &  Jimmy  G.  Qaqish, bsc

 

Abstract: Purpose: To evaluate the plaque removal efficacy and safety of an advanced rotation-oscillation power toothbrush relative to a newly-introduced sonic toothbrush. Methods: This study used a randomized, examiner-blind, two-treatment, four-period, four-sequence crossover design. Subjects received both toothbrushes (Oral-B Triumph and Sonicare FlexCare) and a standard dentifrice from the study site and used each toothbrush at home during an acclimation phase prior to their plaque measurement visits. After abstaining from all oral hygiene for 24 hours, subjects returned to the study site and were assessed with the Rustogi Modified Navy Plaque Index. They then brushed for 2 minutes with their first randomly-assigned toothbrush and post-brushing plaque scores were recorded. This procedure was followed for three additional study visits, with subjects using their normal at-home toothbrush and dentifrice for the 2- to 5-day washout periods between visits. Subjects always abstained from all oral hygiene for 24 hours prior to their visits. Results: 45 subjects completed the study. Both brushes were found to be safe and both significantly reduced plaque after a single brushing. Oral-B Triumph was statistically significantly (P< 0.0001) more effective in plaque removal than Sonicare FlexCare for whole mouth plaque scores, gingival marginal plaque scores and interproximal plaque scores. Compared to Sonicare FlexCare, the adjusted mean plaque reduction scores for Oral-B Triumph were 21%, 23% and 22% greater for whole mouth, marginal and interproximal areas, respectively. (Am J Dent 2008;21:185-188).

   

   

*: Dr. Aaron Biesbrock, The Procter & Gamble Company, 8700 Mason-Montgomery-Road, Mason, OH 45040-9462, USA . E-*: biesbrock.ar@pg.com

 

 

 

In vivo antiplaque efficacy of combined antimicrobial dentifrice

and rinse hygiene regimens

 

Donald  J. White, phd,   Matthew  L.  Barker, phd   &   Malgorzata  Klukowska, dds , phd

 

Abstract: Purpose: To evaluate using digital plaque image analysis the antiplaque efficacy of oral care regimens including use of antimicrobial toothpaste in combination with antimicrobial mouthrinse. Methods: 16 subjects completed the study protocol including: (1) initial treatment phase, all subjects used a standard sodium fluoride dentifrice with 2x/day brushing, (2) second treatment phase, subjects were randomized to two treatment groups: stannous fluoride/sodium hexametaphosphate dentifrice or sodium fluoride triclosan/copolymer dentifrice; (3) third treatment phase, the group using stannous fluoride dentifrice rinsed with alcohol-free cetylpyridinium chloride mouthrinse and the group using triclosan dentifrice rinsed with essential oil mouthrinse. During each phase, plaque levels were assessed in the morning before toothbrushing (AM), post-brushing in the morning (PB) and in the afternoon (PM). Results: Stannous fluoride dentifrice was superior to triclosan dentifrice in plaque growth inhibition between toothbrushing. Both mouthrinses provided additional plaque prevention benefits when used with antimicrobial dentifrices. The cetylpyridinium chloride mouthrinse and stannous fluoride dentifrice regimen was particularly effective, building accretive efficacy over time. Average plaque reductions exceeded 50% vs. sodium fluoride dentifrice alone. Chemotherapeutic dentifrices and rinses increase plaque control used alone and particularly in combination. The stannous fluoride-cetylpyridinium chloride regimen showed the greatest benefits. (Am J Dent 2008;21:189-196).

   

   

*: Dr. Donald J. White, The Procter & Gamble Company, Mason Business Center, 8700 Mason-Montgomery Road, OH 45040, USA. E-*: white.dj.1@pg.com