^{February 2015 Abstracts}

 

In situ bacterial accumulation on dental restorative materials. CLSM/COMSTAT analysis

 

 

Gislaine C. Padovani, dds, ms, phd, Suzana B. P. FÚcio, dds, ms, phd, GlÁucia M. B. Ambrosano, dds, ms, phd, LourenÇo Correr-Sobrinho, dds, ms, phd  &  Regina M. Puppin-Rontani, dds, ms, phd

 

Abstract: Purpose: To evaluate the influence of different restorative materials on the biofilm structure accumulated in situ. Methods: 15 discs of each material (ceramic; resin composite; resin-modified and conventional glass-ionomers; amalgam) were adapted to palatal devices in order to accumulate biofilm in situ, under a cariogenic challenge (20% sucrose solution, 10x/day). After 7 days, the specimens were carefully removed and visualized by confocal laser scanning microscopy (CLSM). The images were analyzed qualitatively (descriptive analysis about cell viability and architecture) and quantitatively using COMSTAT software (area, bio-volume, mean thickness, maximum thickness and roughness coefficient of the biofilm). The statistical analysis was performed by using the Kolmogorov-Smirnov and Kruskal-Wallis tests (P≤ 5%). Results: The medians of the biofilm parameters analyzed showed no statistical difference regarding different materials. However, qualitatively, glass-ionomer cements and amalgam showed visually a prevalence of non-viable cells forming small clusters distributed by the biofilm, and voids were presented in smaller proportion in the biofilm volume compared to composite and ceramic. (Am J Dent 2015;28:3-8).

 

 

 

 

 

 

Mail: Prof. Dr. Regina Maria Puppin-Rontani, Piracicaba Dental School, UNICAMP, Pediatric Dentistry Department, Av: Limeira, no 901, Piracicaba, 13414-900, São Paulo, Brazil.  E-mail: rmpuppin@fop.unicamp.br

 

 

Cytokine levels in plasma and gingival crevicular fluid in chronic periodontitis

 

Xiao-Tao  Chen, mm,  Jing-Yi  Tan, mm,  Li-Hong  Lei, mm & Li-Li   Chen , md

 

Abstract: Purpose: To evaluate the Th1/Th2/Th17 cytokine levels in plasma and gingival crevicular fluid (GCF) from chronic periodontitis patients and healthy controls. Methods: The concentration of interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-17, TNF, and IFN-γ were determined using a flow cytometric multiplex immunoassay (CBA), and was compared between the periodontitis group and the healthy group. Spearman rho coefficient was used to correlate cytokines in GCF in the periodontitis group and the healthy group, respectively. Results: Comparisons of two groups of Th1/Th2/Th17 cytokine levels in plasma and GCF showed no statistically significant differences (P> 0.05), except Th17 (IL-17) level in plasma that was higher in the periodontitis group than the healthy group (P< 0.05). A stronger correlation between IL-17/IL-4 and IL-17/IL-10 was observed in periodontitis patients than in healthy controls. (Am J Dent 2015;28:9-12).

 

 

 

Mail:  Dr. Li-Li Chen, Department of Oral Medicine, The Second Affiliated Hospital, School of Medicine , Zhejiang University, 88 Jiefang Road , Hangzhou , 310009, China .  E-mail:  chenlili_1030@163.com

 

 

Formation of subsurface dentin lesions using a polymicrobial biofilm model

 

Kiyoshi Tomiyama, dds, phd, Yoshiharu Mukai, dds, phd, Hidefumi Kumada, phd, Kiyoko Watanabe, phd, Nobushiro Hamada, dds, phd  &  Toshio Teranaka, dds, phd

 

Abstract: Purpose: To simulate an oral demineralization environment by multiple species of bacteria by inducing subsurface dentin lesions with a polymicrobial biofilm model. Methods: Polymicrobial biofilms consisting of multiple species of bacteria were generated from stimulated saliva using a high-throughput active attachment model. Biofilms were grown on dentin specimens in McBain medium containing 0, 0.2 or 2.5 ppm F and on glass without fluoride for 192 hours. The medium was refreshed twice daily, after 10 and 14 hours, until 72 hours, followed by treatment for 5 minutes with 400 ppm fluoride. Specimens were recovered after 192 hours. The number of colony forming units (CFU) was measured, and integrated mineral loss (IML) was determined by transversal micro-radiography. Results: Mineral profiles in specimens grown with 0.2F and 2.5F revealed surface layers and initial lesions distinct from those grown with 0F. IML was significantly lower with 0.2F and 2.5F than with 0F (P< 0.05), although CFUs were similar. CFUs of biofilms grown on dentin in medium containing 0F were 10-fold higher than on glass (P< 0.05). Subsurface lesions on dentin formed consistently, with their growth progression inhibited by application of fluoride. To our knowledge, this is the first report describing the induction of subsurface dentin lesions by a polymicrobial biofilm model, and this model may be useful for studies of demineralization supporting in situ and in vivo models. (Am J Dent 2015;28:13-17).

 

 

 

 

 

 

Mail: Dr. Yoshiharu Mukai, Department of Cariology and Restorative Dentistry, Graduate School of Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, Japan. E-mail: mukai@kdu.ac.jp

 

In vitro effect of calcium-containing prescription-strength fluoride toothpastes on bovine enamel erosion under hyposalivation-simulating conditions

 

TaÍs  Scaramucci, dds, phd,  Alessandra  B.  Borges, dds, mds, phd,  Frank  Lippert, msc, phd,

Domenick  T.  Zero, dds, mds   &  Anderson  T.  Hara, dds, msd, phd

 

Abstract: Purpose: To evaluate the ability of calcium-containing prescription-strength fluoride (F) toothpastes in preventing enamel erosion under low salivary flow simulating conditions. Methods: Enamel and dentin bovine specimens were assigned to the following groups: A – placebo; B - 1,100 ppm F/NaF (Aquafresh Advanced); C - 5,000 ppm F/NaF (Prevident 5000 Booster); D - 5000 ppm F/NaF+calcium sodium phosphosilicate (Topex Renew); and E - 5,000 ppm F/NaF+tri-calcium phosphate (Clinpro 5000). Specimens were positioned in custom-made devices, creating a sealed chamber on the surface, connected to peristaltic pumps. Citric acid was injected into the chamber for 2 minutes, followed by artificial saliva (0.05 ml/minute), for 60 minutes, 4×/day, for 3 days. Aquafresh was also tested under normal salivary flow (0.5 ml/minute), as reference (Group F). Specimens were exposed to the toothpastes for 2 minutes, 2×/day. After cycling, surface loss (SL) and concentration of loosely- and firmly-bound F were determined. Data were analyzed by ANOVA. Results: Group A (placebo) presented highest surface loss (SL), while Group F had the lowest, for both substrates. For enamel, none of the dentifrices differed from Group B or among each other. For dentin, none of the dentifrices differed from Group B, but Group E showed greater protection than Group C. Group E presented the highest F concentrations for both substrates, only matched by Group D for firmly-bound fluoride on enamel. All fluoridated dentifrices tested reduced SL, with no additional benefit from higher F concentrations. Some formulations, especially Clinpro 5000, increased F availability on the dental substrates, but no further erosion protection was observed. (Am J Dent 2015;28:18-22).

 

 

 

Mail: Dr. Anderson T. Hara, Oral Health Research Institute, Department of Preventive and Community Dentistry, Indiana University School of Dentistry, 415 N. Lansing Street, Indianapolis, IN  46202-2876, USA.  E-mail: ahara@iu.edu

 

 

In vivo evaluation of fluoride dentifrice and diet control on the demineralization/remineralization process using laser readouts at the margin of the orthodontic bracket/enamel interface

 

Vanessa  Salvadego  de  Queiroz, dds, ms, phd,   Paulo  Roberto  Aranha  Nouer, dds, ms, phd,

CÍnthia  Pereira  Machado  Tabchoury, pharmd, ms, phd,   Ynara  Bosco de Oliveira Lima-Arsati, dds, ms, phd &  Darcy  FlÁvio  Nouer, dds, ms, phd.

 

Abstract: Purpose: To evaluate, in vivo, the effect of fluoride dentifrice and diet control on the deminerali-zation/remineralization processes at the margin of bracket/enamel interface bonded with four different bonding materials, using optical microscopy and fluorescent laser (DIAGNOdent). Methods: Premolars in 35 subjects (11 to 20 years old) were divided into Group 1 (n= 15) and Group 2 (n= 20). Four bracket/enamel interfaces (near points) and four points at a distance of 2 mm (distant points) were observed. Evaluations were made at the following times: 15 days before bracket bonding (T0), on day of bonding (T1), 1 week after bonding (T2), and 4 weeks after bonding (T3). Subjects received fluoride dentifrice, and toothbrush and were instructed to brush 3×/day, after main meals. Group 1 received the instructions at T1 and Group 2 at T0 and these were reinforced weekly. The Microarch brackets were bonded with four materials: Transbond XT; Concise Ortodôntico; Fuji Ortho LC and Monolok2. DIAGNOdent laser readouts were used for comparison. Results: Data were statistically analyzed by Mann-Whitney, Wilcoxon and Friedman tests (P< 0.05). Higher readouts were found at nearer points than at distant points; Group 2 presented lower readouts than Group 1; No differences were observed among bonding materials. (Am J Dent 2015;28:23-27).

 

 

 

 

Mail: Dr. Vanessa Salvadego de Queiroz, Department of Clinical Pathology, School of Medical Sciences, FCM State University of Campinas - UNICAMP. Campinas, São Paulo 13083-970, Brazil. E-mail: vanessasalvadego@gmail.com

 

 

Chlorhexidine does not improve but preserves bond strength to eroded dentin

 

Luciana  FÁvaro  Francisconi-dos-Rios, dds, ms phd,  Marcela  Pagani  Calabria, dds, ms phd, Leslie  Caroll  Casas-Apayco, dds, ms phd,  Heitor  Marques  HonÓrio, dds, ms phd, Marcela  Rocha de Oliveira Carrilho, dds, ms phd, JosÉ Carlos Pereira, dds, ms phd  &  Linda Wang, dds, ms phd

 

Abstract: Purpose: To evaluate the effect of aqueous solutions of chlorhexidine digluconate (CHX) in different concentrations on bond strength to eroded dentin up to 6 months, using normal dentin as a control. Methods: Exposed flat dentin of extracted third molars was only ground with 600-grit SiC paper/1 minute (normal dentin - N), or subsequently eroded by a regular-cola soft-drink (eroded dentin - E). N and E were acid-etched, washed, dried and rehydrated with 1.5 µL, respectively, of distillated water (control - NC / EC); of 0.004% CHX (N0.004% / E0.004%); or of 2% CHX (N2% / E2%). Adper Single Bond 2 was applied in all specimens and resin composite buildups were constructed with Filtek Z350. Specimens were sectioned in beams, which were tested (µTBS) immediately or after 6 months of aging. Results: Microtensile bond strength to eroded dentin was always significantly lower than that to normal dentin. Application of tested CHX solutions did not exert a significant effect immediately; however, after aging, the 2% CHX prevented abrupt bond strength loss both to eroded and normal dentin. (Am J Dent 2015;28:28-32).

 

 

Mail: Dr. Linda Wang, Alameda Octávio Pinheiro Brisolla, 9-75, Bauru/SP - 17012-901, Brazil. E-mail: wang.linda @usp.br;  wang.linda@uol.com.br

 

 

Evaluation of nanohydroxyapatite-containing toothpaste for occluding dentin tubules

 

Bennett  T.  Amaechi, bds, msc, phd,  Sapna  M.  Mathews, bds, ms,  Karthikeyan  Ramalingam, bsc, phd &  Poornima  K.  Mensinkai, bds, ms

 

Abstract: Purpose: To compare dentin tubule occlusion by dentifrices containing either nanohydroxyapatite (10%nHAP and 15%nHAP), sodium monofluorophosphate (Na-MFP) or NovaMin (NovaMin). Methods: All 80 participants wore four intraoral appliances bearing dentin blocks while using one of the four test dentifrices (n= 20/dentifrice) twice daily for 14 days. The four appliances were removed in pairs after 7 and 14 days. One treated block from each of the test periods (7 and 14 days) and their untreated controls were examined with SEM to determine the level of tubule occlusion. The remaining two treated blocks and their controls were used to determine tubule permeability to dye solution. Effectiveness was compared statistically (ANOVA/Tukey’s) based on % area covered by deposited precipitate layer (%DPL), % dye penetration inhibition (%DPI) and percentage of fully-open (%FOT), partially-occluded (%POT) and completely-occluded (%COT) tubules in each block calculated relative to the number of tubules in their control blocks. Results: SEM showed increased %COT and %DPL overtime. After 7 and 14 days, %COT, %POT, %DPL and %DPI were significantly lower with Na-MFP when compared to 10%nHAP (P < 0.01), NovaMin (P< 0.05) and 15%nHAP (P< 0.001), the three of which were not significantly different from each other in those four variables. A reverse trend was observed with %FOT (P< 0.001). Within the same dentifrice, no difference in %COT, %POT, %FOT, %DPI and %DPL after 7 and 14 days, except with Na-MFP in which %DPL significantly (P< 0.05) increased with usage. In conclusion, nanohydroxyapatite-containing and NovaMin-containing toothpastes showed equal and more effectiveness in occluding dentin tubules than Na-MFP toothpaste. (Am J Dent 2015;28:33-39).

 

 

 

 

 

Mail: Dr. Bennett T. Amaechi, Department of Comprehensive Dentistry, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229-3900, USA. E-mail: amaechi@uthscsa.edu

 

Efficacy of a combined in-office/home-use desensitizing system containing 8% arginine and calcium carbonate in reducing dentin hypersensitivity: An 8-week randomized clinical study

 

Isabela Lima FranÇa, dds, ms, Enilson Antonio Sallum, dds, phd,  Hugo Felipe do Vale, dds, phd,

MÁrcio Zaffalon Casati, dds, phd,  Antonio Wilson Sallum, dds, phd  &  Bernal Stewart, bseng msc

 

Abstract: Purpose: To determine the efficacy in reducing dentin hypersensitivity (DHS) of a combined in-office and home-use desensitizing system, each product containing 8% arginine and calcium carbonate (Test), following a dental scaling procedure, compared to the combination of a conventional prophylactic paste and a potassium nitrate dentifrice (Control), in a group of patients with known dentin hypersensitivity. Methods: An 8-week clinical study, with 50 subjects, was conducted in Piracicaba, São Paulo, Brazil, using a double-blind/two treatment design. Air blast sensitivity assessments were used to compare the efficacy of the two approaches using both the Schiff scale as well as a Visual Analogue Scale (VAS). Results: Immediately after prophylaxis, the Test treatment provided significant reduction in DHS when compared to baseline values (VAS= 26.2% and Schiff= 29.1%), while for Control treatment this difference was not statistically significant (VAS= 8.1% and Schiff= 6.6%). The comparison between groups after prophylaxis showed a greater DHS reduction for the Test treatment (P< 0.05). The reductions in DHS after 2, 4 and 8 weeks were significant for both groups, however, when considering Schiff scale, the Test treatment provided greater DHS reduction after 2 weeks (44.5% for Test versus 27.7% for Control) and 4 weeks (55.2% for Test and 40.5% for Control), while after 8 weeks there was no significant difference between groups (71.1% for Test versus 61.1% for Control). (Am J Dent 2015;28:45-50).

 

 

Mail: Dr. Enilson Antonio Sallum, Av. Limeira, 901, Areão, Piracicaba, São Paulo, Brazil  E-mail: easallum@fop.unicamp.br

 

An in vitro evaluation of the effect of fluoride products on white spot lesion remineralization

 

Agnieszka Mielczarek, md, phd, Tomasz Gedrange, md, phd   &  Joanna Michalik, msc

 

 

Abstract: Purpose: To compare the effect of combinations of fluoride (F) products on remineralization of caries-like lesions. Methods: Demineralized human enamel specimens were assessed by surface microhardness (SMH), stratified and allocated to five treatments groups: (1) Toothpaste containing 1% nano hydroxyapatite (HAP) + 1,450 ppm F; (2) Tooth mousse containing 10% casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) + 900 ppm F plus F toothpaste (1,450 ppm F as NaF); (3) F varnish containing 22,600 ppm F plus F toothpaste (1,450 ppm F as NaF); (4) F toothpaste (1,450 ppm F as NaF); and (5) placebo - distilled water (P). Each group was treated in a 21-day pH-cycling model. Groups 1, 4 and 5 were treated 2×/day. In Group 3, the tooth mousse was administered 1×/day plus 2×/day F toothpaste treatment. In Group 4, F varnish was administered 1×/week plus 2×/day treatment with F toothpaste. After cycling, SMH was re-measured and cross-sectional microhardness measurements were taken. Results: Groups 1-4 produced significant rehardening of enamel. In the superficial layer (25-50 μm deep) significantly higher mineralization (up to 83%, by Volume (V), P< 0.0001) was achieved for Groups 2 and 3. In the area of 75-100 μm deep, the highest mineralization was observed for Groups 1 and 4 (V%= 68-83%). (Am J Dent 2015;28:51-56).

 

 

 

 

 

 

Mail: Dr. Agnieszka Mielczarek, Department of Conservative Dentistry, Medical University of Warsaw, Miodowa 18, 00-246 Warsaw, Poland. E-mail: agnieszka.mielczarek@wum.edu.pl

 

 

Antimicrobial effects of carbamide peroxide against a polymicrobial biofilm model

 

Haruhiko Hasegawa, dds,  Kiyoshi Tomiyama, dds, phd, Hidefumi Kumada, phd,  Akira Kawata, dds, phd, Kazuyoshi Higashi, phd,  Osamu Takahashi, dds, phd,  Nobushiro Hamada, dds, phd  &   Yoshiharu Mukai, dds, phd

 

Abstract: Purpose: To investigate the in vitro antimicrobial effects of carbamide peroxide (CP) and CP-based home bleaching agents against polymicrobial (PM) biofilms. Methods: Using a high-throughput active attachment model, PM biofilms were cultured on glass coverslips by diluting the stimulated saliva of one healthy adult. All experiments were performed anaerobically in McBain medium, which was refreshed twice daily. After biofilm formation for 24 or 72 hours, the biofilms were treated with 0.5%, 2.5%, 5%, or 10% CP, 20-fold dilutions of HiLite Shade Up (HS) or Opalescence Regular (OR), 0.2% chlorhexidine digluconate (CHX), 0.2% NaF, or deionized water (n = 10 each). Biofilms were dispersed and the number of colony forming units (CFU) was measured on tryptic soy agar blood plates. Coverslips containing 72-hour biofilms treated with 0.5% and 10% CP and deionized water were stained and scanned by confocal laser scanning microscopy (CLSM). Results: Treatment of 24- and 72-hour biofilms with HS, OR and CH yielded significantly fewer colonies than treatment with water or 0.2% NaF. No growing colonies were observed after treatment with 10% CP. CLSM showed that the percentage of dead bacteria increased as the concentration of CP increased. (Am J Dent 2015;28:57-60).

 

 

 

 

Mail: Dr. Yoshiharu Mukai, Department of Cariology and Restorative Dentistry, Graduate School of Dentistry, Kanagawa Dental University 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, Japan. E-mail: mukai@kdu.ac.jp

 

Difference in effectiveness between strontium acetate and arginine-based toothpastes to relieve dentin hypersensitivity. A systematic review

 

Marcela BaraÚna Magno,  GlÁucia Cristina Rodrigues Nascimento, Natasha Kiss Santos da Penha, Oscar Faciola Pessoa, dds, msd, phd, Sandro Cordeiro Loretto, dds, msd, phd  &  Lucianne Cople Maia, dds, msd, phd

 

Abstract: Purpose: To present an overview of clinical evidence of strontium acetate and arginine-based toothpastes, in order to determine which of these substances was the most effective to relieve dentin hypersensitivity (DH). Methods: An electronic search was performed in PubMed, EMBASE, The Cochrane Library, LILACS, Web of Science and Open Grey databases. The search strategy included MeSH terms, synonyms and keywords with no language or date restriction. Randomized controlled clinical trial studies that compared the effectiveness of arginine/calcium carbonate and strontium acetate toothpaste were included. The risk of bias in the included studies was assessed and classified through the Cochrane Collaboration's common scheme for bias. Data were subgrouped and heterogeneity was tested via comprehensive meta-analysis. Results: A total of 3,883 potentially relevant studies were identified. After title and abstract examination, only six studies fulfilled the eligibility criteria and were classified as having a “low risk of bias”.  The majority of studies found better results for arginine/calcium carbonate in comparison with strontium acetate in alleviating DH. Only one study reported superior efficacy of strontium acetate, and only for tactile stimuli, after 8 weeks of home use. The arginine/calcium carbonate-based toothpaste provided a higher level of efficacy in terms of DH relief than the strontium-based toothpaste. (Am J Dent 2015;28:40-44).

 

 

Mail: Dr. Lucianne Cople Maia, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil, Department of Pediatric Dentistry and Orthodontics, School of Dentistry, Av Prof. Rodolpho Paulo Rocco, 325 Ilha do Fundão, Rio de Janeiro, RJ, CEP:21941-617, Brazil. E-mail: rorefa@terra.com.br