Oral cancer: Current and future diagnostic techniques

 

Crispian Scully, cbe, phd, md, mds, mrcs, fdsrcps, ffdrcsi, fdsrcs, fdsrcse, frcpath, fmedsci, fhea, fucl, dsc, dchd, DMed(HC), José  V. Bagan, dds, phd, md, Colin  Hopper, md, frcs(ed), fdsrcs  &  Joel  B. Epstein, dmd, msd, frcd(c), fdsrcse

 

Abstract: Oral cancer is among the 10 most common cancers worldwide, and is especially seen in disadvantaged elderly males. Early detection and prompt treatment offer the best chance for cure. As patient awareness regarding the danger of oral cancer increases, the demand for “screening” is expected to increase. The signs and symptoms of oral cancer often resemble less serious conditions more commonly found and similarly usually presenting as a lump, red or white patch or ulcer. If any such lesion does not heal within 3 weeks, a malignancy or some other serious disorder must be excluded and a biopsy may be indicated. Dental health care workers have a duty to detect benign and potentially malignant oral lesions such as oral cancer and are generally the best trained health care professionals in this field. Prompt referral to an appropriate specialist allows for the best management but, if this is not feasible, the dental practitioner should take the biopsy which should be sent to an oral/head and neck pathologist for histological evaluation. (Am J Dent 2008;21:199-209).

 

 

*: Prof. Crispian Scully, UCL Eastman Dental Institute, 256 Gray’s Inn Road, University College London, London WC1X 8LD, United Kingdom.  E-*: c.scully@eastman.ucl.ac.uk

 

 

Clinical evaluation of a dentifrice containing calcium sodium phosphosilicate (NovaMin) for the treatment of dentin hypersensitivity

 

Min  Quan  Du, dds, ms, phd,  Zhuan  Bian, dds, ms, phd,  Han  Jiang, dds, ms, phd,  David  C. Greenspan, phd, Anora K. Burwell, ms,  Jipin  Zhong, phd  &  Bao  Jun  Tai, dds

 

Abstract: Purpose: To evaluate the efficacy of a dentifrice containing calcium sodium phosphosilicate (NovaMin) study versus a placebo and a commercially-available SrCl₂ containing dentifrice for the treatment of dentin hyper-sensitivity. Methods: This was a 6-week, randomized, parallel-arm, double-blind clinical study. 71 subjects ranging in age from 21 to 56 years old completed the study. Evaporative and thermal stimuli were used to measure pain using a VAS scale. Measurements were obtained at baseline, 2 weeks and 6 weeks. Results: The placebo and the NovaMin groups showed a statistically significant decrease in sensitivity by both measures after 6 weeks (P< 0.05). The SrCl₂ group showed a statistically significant decrease from baseline at the 2-week time point, but not at the 6-week time point for the evaporative stimulus. The percent reduction in sensitivity at 6 weeks for the NovaMin test group was 35% for air and 39% for cold water stimulus, versus 11% for air and 22% for cold water for the SrCl₂ paste. The reductions for the placebo paste were 21% for the air stimulus and 18% for water. A cross tabulation measure of the reduction in sensitivity at each time point for all three treatments showed that the NovaMin product was more effective than either of the other products. For the air stimulus in the NovaMin group, 58% of subjects improved at each time point compared with 26% for the SrCl₂ group and 20% for the placebo group. These results demonstrate that the NovaMin dentifrice was more effective at reducing sensitivity compared with a commercial dentifrice and placebo control. (Am J Dent 2008;21:210-214).

   

   

*: Prof. Bao Jun Tai, Key Laboratory for Oral Biomedical Engineering of the Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan, 430079, P.R. China. E-*: taibaojun@126.com

 

 

 

Effect of pre-heating on depth of cure and surface hardness

of light-polymerized resin composites

 

Carlos  A.  Muñoz, dds, msd,  Peter  R.  Bond, dds, ms,  Jenny  Sy-Muñoz, dds, msd,  Daniel  Tan, dds &  John  Peterson, dds, ms

 

Abstract: Purpose: To evaluate the depth of cure and surface hardness of two resin composites when subjected to three preheating temperatures, three polymerization times and two types of curing lights. Methods: Two resin composites were used in this study (Esthet-X and TPH), three polymerization times (10, 20, 40 seconds), three preheating temperatures (70, 100, 140°F/21.1, 37.7 and 60°C), and two curing lights (halogen and LED). For depth of cure measurements, 180 specimens (4 mm in diameter and 2 mm in depth) were made for 36 combinations of variables. Four Knoop hardness measurements were obtained from both the top and bottom surfaces.  For the surface hardness, another 180 (4 x 6 mm) cylindrical specimens were fabricated. Each specimen was sectioned in half and hardness measurements were made at 0.5 mm intervals. Statistical analyses were performed using the multifactor ANOVA at a level of significance of α = 0.05. Results: For depth of cure, there was a statistical difference among all the main effects (time, temperature and curing light) for both composites (P> 0.001) when the % difference from the top was analyzed. Results indicate that there was an increase in hardness as the temperature of the composite was increased from 70 to 140°F for both composites for either the top or the bottom. The percent difference in hardness was greater when the LED curing light was used compared to the halogen curing light. Overall there was a greater change in hardness when the resin composite was polymerized at 140°F. Although the ISO standard was not met in many cases, there was a significant increase in hardness on both the top and bottom as temperature and curing time increased (P< 0.001). Results for the surface hardness showed that there was a significant statistical difference (P< 0.001) in hardness when the surface hardness at 0.5 and 3.5 mm were analyzed separately. There was a general increase in surface hardness for both the hybrid and microhybrid as time and temperature increased. For both hybrid and microhybrid groups, as the temperature increased, there was an increase in hardness and it was statistically different (P< 0.001). When the percent difference between 70 and 100°F or 70 and 140°F was evaluated, the greatest increase occurred between the 70 and 140°F and minimal increase between 100 and 140°F. Overall, the LED curing light provided a greater surface hardness for the hybrid at both depths than the halogen curing light. For the microhybrid, the halogen curing light provided the greatest surface hardness when the resin was polymerized for 40 seconds. (Am J Dent 2008;21:215-222).

 

 

*: Dr. Carlos A. Muñoz, School of Dental Medicine, The State University of New York at Buffalo, Squire Hall Room 215, 3435 Main St., Buffalo, NY 14214, USA.  

E-*: cmunoz@buffalo.edu

 

 

Hardness and elasticity of caries-affected and sound primary tooth dentin bonded with 4-META one-step self-etch adhesives

 

Yumiko Hosoya, dds, phd,  Franklin R. Tay, bdsc (hons), phd, Shoichi Miyakoshi, phd  &  David H. Pashley, dds, phd

 

Abstract: Purpose: To evaluate the quality of the interface of sound and carious primary tooth dentin bonded with two 4-META one-step self-etch adhesives. Methods: 12 sound and 12 carious primary molars were bonded with AQ Bond Plus (AQBP; Sun Medical) or Hybrid Bond (HB; Sun Medical) and restored with Clearfil Protect Liner F (Kuraray Medical Inc.). After 24 hours of water immersion, the teeth were sectioned and polished. Resin-dentin interfaces were measured with a nano-indentation tester and hardness and Young’s modulus were calculated. Data were analyzed using one-way or two-way ANOVA and Fisher’s PLSD test with α=0.05. Resin-dentin interfaces were also observed with SEM and TEM. Ammoniacal silver nitrate was used as a tracer for TEM observation. Results: Hardness and Young’s modulus of the interfacial dentin were significantly lower than the underlying intact dentin except for the carious-AQBP group. However, there was no significant difference of hardness and Young's moduli of the interfacial dentin among all groups. TEM revealed extensive interfacial nanoleakage in sound dentin bonded with either AQBP or HB. For the carious teeth, nanoleakage was absent in the hybrid layers bonded with the two adhesives. However, extensive silver deposits were identified from the subsurface, porous caries-affected dentin. (Am J Dent 2008;21:223-228).

 

 

*: Dr. Yumiko Hosoya, Department of Pediatric Dentistry, Course of Medical and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1, Sakamoto, Nagasaki, 852-8588, Japan. E-*: hosoya@nagasaki-u.ac.jp

 

 

Translucency of varied brand and shade of resin composites

 

Bin  Yu, mche  &  Yong-Keun  Lee , dds , phd

 

Abstract: Purpose: To measure and classify the translucency of varied brands and shades of resin composites. Methods: Eight light-curing resin composites, with a total of 41 shades, were investigated. The color of specimens, 12 mm in diameter and 1 mm in thickness, was measured after polymerization on a reflection spectrophotometer with the SCE geometry under the illuminant D65 over white and black backgrounds. The translucency parameter (TP) and contrast ratio (CR) were calculated and compared. The influence of shade on TP values in each brand of resin composites was analyzed with one-way ANOVA. Results: The range of TP values varied from 8.5 to 20.6, which was significantly influenced by the shade designation of resin composites (P< 0.05). In each brand, TP values varied by the shade designation. The range of mean translucency parameter value by the shade group, such as A1, A2, A3, A3.5 and B2 group, was 15.4 to 17.2. Translucency parameter was highly correlated with mean contrast ratio value (r = -0.84). (Am J Dent 2008;21:229-232).

 

 

*: Dr. Yong-Keun Lee, Department of Dental Biomaterials Science, School of Dentistry, Seoul National University, 28 Yeongeon-dong, Jongro-gu, Seoul, Korea. 

E-*: ykleedm@snu.ac.kr

 

 

 

Effect of hydrostatic pulpal water pressure on microtensile bond strength of self-etch adhesives to dentin

 

Ali I. Abdalla, phd,  Hussein Y. ElSayed,  phd   &   Franklin García-Godoy,  dds, ms

 

Abstract: Purpose: To evaluate the effect of pulpal pressure on the microtensile bond strength of four self-etch adhesives to dentin. A total-etch adhesive was added for comparison. Methods: 60 freshly extracted human third molars were selected. For each tooth, the root was removed below the cemento-enamel junction. A second parallel section was made to remove the coronal enamel to form a crown segment. The root portion of the resulting crown segment was cemented to a Plexiglas platform using cyanoacrylate cement. The crown segment was then connected with a plastic tube to a water column to produce a pressure of 20 cm H₂O at the prepared dentin surface of the crown segment. The adhesive materials were: a total-etch adhesive (Scotchbond 1) and four self-etch adhesives (Clearfil SE Bond, Hybrid Bond, Futurabond NR, and AdheSE Bond). The tested adhesives were applied to the dentin surface in three test procedures: applied to dentin without pulpal pressure, applied to dentin with pulpal pressure for 24 hours, and applied to dentin with pulpal pressure and the pressure was maintained for 6 months during storage. Grandio resin composite was placed in 3-4 layers to a height of 5-6 mm to form a crown segment. For bond strength measurement, the composite-dentin segment was removed from the Plexiglas. This segment was then sectioned to prepare the specimens for microtensile bond measurement. Results: None of the tested adhesives showed bond strength reduction when applied to dentin supplied with water pressure. After 6 months of pulpal pressure, Scotchbond 1, Clearfil SE Bond and AdheSE Bond showed significant reduction in bond strength (P< 0.05). In contrast, Futurabond NR and Hybrid Bond were not significantly affected. (Am J Dent 2008; 21:233-238).

 

   

*: Dr Ali I. Abdalla, Dept. of Restorative Dentistry, Faculty of Dentistry, University of Tanta , Tanta , Egypt . E-*: ali_abdalla79@yahoo.com

 

 

 

The influence of dynamic fatigue loading on the separate components

of the bracket-cement-enamel system

 

Tjalling J. Algera, dds, Cornelis J. Kleverlaan, phd, Birte Prahl-Andersen, dds, phd,

&  Albert J. Feilzer, dds, phd

 

Abstract: Purpose: To evaluate the influence of cyclic loading and type of adhesive on the shear bond strength of the bracket-cement-enamel bond. Methods: The materials studied were: Transbond XT (a Bis-GMA resin composite cement), Fuji Ortho LC (a resin-modified glass-ionomer cement), and Fuji IX Fast (a conventional glass-ionomer cement). The shear bond strength (SBS) and the shear bond fatigue limits (SBFL) were determined after 72-hour storage in 37°C water for the cement itself, the button-cement interface, the cement-enamel interface, and the bracket-cement-enamel system. The SBFL was determined with the aid of the “staircase method” at 10,000 cycles. The results were analyzed using ANOVA and Tukey HSD post hoc test (P< 0.05). Results: ANOVA showed significant differences between the SBS of the materials. Fatigue was observed in all substrate combinations, with the exception for the Fuji IX Fast cement-enamel and the Fuji Ortho LC bracket-cement-enamel combinations. (Am J Dent 2008;21:239-243).

 

 

*: Dr. C.J. Kleverlaan, ACTA, Department of Dental Material Science, Louwesweg 1, 1066 EA Amsterdam, E-*: dental.materials@acta.nl

 

 

 

Comparison of detachment forces of two implant overdenture

attachment types: Effect of detachment speed

 

Steven R. Jefferies, ms, dds, phd,  Daniel  W. Boston, dmd,  Michael P. Damrow, ba  &  Colin T. Galbraith, bs  

 

Abstract: Purpose: To compare detachment (retentive) force for overdenture retainers used with conventional and “mini” implant designs over a range of different detachment (separation) speeds. Methods: Two dental implant fixtures [Sendax MDI (“mini” dental implant) and Replace Select (conventional dental implant design)] with ball attachments were mounted in brass cylinders. Corresponding attachments were processed into acrylic denture resin blocks and connected to the ball attachments on the implants. The fixture/attachment assemblies were placed in an Instron testing system under ambient room temperature and humidity conditions (approximately 72°F and 35-65% relative humidity). The assemblies were separated under tensile load at 11 speeds from 10-500 mm/minute with 10 replicates at each speed. Maximum detachment (separation) force was recorded. Mean, minimum, maximum, standard deviation and range of maximum detachment (separation) force was calculated. To test the hypothesis “the Sendax MDI and the Replace Select have the same average detachment force, at a given detachment speed”, one-way ANOVA was performed. To test the hypothesis that “all detachment speeds have the same average maximum detachment force”, one-way ANOVA was performed. To test the hypothesis that “the distribution of maximum detachment forces is the same for all detachment speeds”, non-parametric Kruskal-Wallis analysis was performed. Results: For Replace Select, the mean of the maximum force varied from 6.02-3.46 N with a downward trend as detachment speed increased.  For Sendax MDI, the mean of the maximum force varied from 3.43-2.86 N. One-way ANOVA and Kruskal-Wallis analyses supported rejection of the hypotheses stated above with more than 99.99% confidence. Within the limitations of this study, the retentive properties of the Sendax MDI and the Replace Select attachment properties were different. Detachment speed had an effect on separation force for the two attachments in this study. Given the range of velocities possible in masticatory function; implant overdenture attachments, optimally, should be evaluated at more than one detachment speed to evaluate clinically-relevant, strain-rate behavior. (Am J Dent 2008;21:244-250).

   

   

*: Dr. Steven R. Jefferies, Maurice H. Kornberg School of Dentistry, Temple University , 3223 North Broad Street, Philadelphia , PA 19140 , USA . E-*: steven.jefferies@temple.edu

 

 

 

Influence of occlusal access on demineralized dentin removal

in the Atraumatic Restorative Treatment ( ART ) approach

 

Maria Fidela Lima Navarro, dds , phd,   Cynthia Junqueira Rigolon, dds , ms,

Terezinha Jesus Esteves Barata, dds , ms, phd,   Eduardo Bresciane, dds , ms, phd,

Ticiane Cestari Fagundes, dds , ms   &   Mathilde C. Peters, dds , phd

 

Abstract: Purpose: To verify the influence of cavity access diameter on demineralized dentin removal in the ART approach. Methods: 40 non-carious human premolars were randomly divided into four groups. The occlusal surface was ground flat and the teeth were sectioned mesio-distally. The hemi-sections were reassembled and occlusal access preparations were carried out using ball-shaped diamonds. The resulting size of the occlusal opening was 1.0 mm, 1.4 mm, 1.6 mm and 1.8 mm for Groups A, B, C, and D, respectively. Standardized artificial carious lesions were created and demineralized dentin was excavated. After excavation, the cavities were analyzed using: (a) the tactile method, (b) caries-detection dye to stain demineralized dentin, as proposed by Smales & Fang, and (c) Demineralized Tissue Removal index, as proposed in this study. Statistical analysis was performed using Fisher, Spearman correlation coefficient, kappa, Kruskal-Wallis and Miller tests (P< 0.05). Results: The three methods of evaluation showed no significant difference between Groups A vs. B, and C vs. D, while statistically significant differences were observed between Groups A vs. C, A vs. D, B vs. C and B vs. D. Based on the results of this study, the size of occlusal access significantly affected the efficacy of demineralized tissue removal. (Am J Dent 2008;21:251-254).

   

 

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

 

 

 

Cytotoxic effects and pulpal response caused by a mineral trioxide aggregate formulation and calcium hydroxide

 

Carlos Alberto de Souza Costa, dds , ms, phd, Paulo Tobias Duarte, dds , ms,  

Pedro Paulo Chaves de  Souza, dds , ms, phd, Elisa Maria Aparecida Giro, dds , ms, phd  &  Josimeri Hebling, dds , ms, phd

 

Abstract: Purpose: To evaluate the in vivo pulpal response after pulpotomy with different capping agents. In addition, the in vitro cytotoxic effects of both materials were assessed by applying them on culture of pulp cells. Methods: For the in vivo test, the coronal pulp of 28 teeth of dogs was mechanically removed and the root pulps were capped with the following dental materials: Group 1: Pro-Root MTA (PRMTA); and Group 2 (control): calcium hydroxide saline paste (CH). After 60 days, the animals were sacrificed and the teeth processed for histological analysis. In the in vitro test, experimental extracts obtained from both capping agents were applied on the cultured MDPC-23 odontoblast-like cells. Results: In the root pulps capped with PRMTA or CH, coagulation necrosis partially replaced by dystrophic calcification as well as tubular dentin matrix laid down by elongated pulp cells was observed. None or mild inflammatory response occurred beneath the capped pulpal wound. Regarding the pulpal response, PRMTA and CH presented no statistical difference. However, the teeth capped CH presented greater healthy pulp loss which resulted in convex shape of the hard barrier than PRMTA. When applied on the cultured cells, it was demonstrated that PRMTA and CH solutions decreased the cell metabolic activity by 9.9% and 29.4%, respectively. CH caused higher cytotoxic effects to the MDPC-23 cells as well as deeper healthy pulp tissue loss than PRMTA. However, similar sequence of healing occurred after pulpotomy with both dental materials. (Am J Dent 2008;21:255-261).

   

   

*: Dr. Carlos Alberto de Souza Costa, University of São Paulo State/UNESP, Rua Humaitá, 1680, CEP: 14.801-903, CP: 331 – Centro, Araraquara, SP, Brazil. 

E-*: casouzac@foar.unesp.br

 

 

 

Histological evaluation of mineral trioxide aggregate and calcium hydroxide in direct pulp capping of human immature permanent teeth

 

Leszek Sawicki, bds, phd,  Cornelis  H.  Pameijer, dmd, dsc, phd,  Katarzyna  Emerich, phd, dds, & Barbara  Adamowicz-Klepalska, phd, dmd

 

 

Abstract: Purpose: To evaluate histological findings in human immature permanent premolars scheduled for extraction for orthodontic reasons, in which mechanical pulp exposures were capped with white ProRoot Mineral Trioxide Aggregate (WMTA) or calcium hydroxide (CH). Methods: Forty-eight human immature premolars in 23 patients (age 10-18 years) were randomly treated with WMTA or CH. After rubber dam isolation Cl I cavities were prepared and the pulps exposed. After hemostasis the pulps were capped with either material. The preparations were restored using an acid etch, bonding agent, flowable composite and composite resin technique. The teeth were extracted after 47 to 609 days and processed for routine histological examination, stained with hematoxylin and eosin and Brown and Brenn for recognition of bacteria. Statistical analyses of inflammation, bridge formation and bacterial leakage were performed using a Chi-square test and ANOVA. Results: Forty-four of 48 teeth were suitable for microscopic evaluation, 30 with WMTA, 14 with CH. Of the WMTA group, 29 teeth were vital, 28 had formed a bridge, and one specimen had failed. Twelve of 14 teeth with CH were vital, while three teeth failed to form a bridge. No statistically significant differences between WMTA and CH were found, except for superficial and deep inflammatory cell response (P≤ 0.05). Pulp capping of intentionally exposed human immature premolars performed slightly better when using MTA. (Am J Dent 2008;21:262-266).

 

 

 

*: Dr. Leszek Sawicki, Department of Pediatric Dentistry, Medical University of Gdansk, ul E. Orzeszkowej 18, 80-208 Gdańsk, Poland. E-*: sawicki@endodoncja.pl

 

 

Survival of glass fiber post restorations over 5 years

 

Michael  Naumann, dds, dr med dent,  Sven  Reich, dds, dr med dent,  Frank  P.  Nothdurft, dds, dr med dent, Florian  Beuer, dds, dr med dent, Jörg F. Schirrmeister, dds, dr med dent 

&  Thomas  Dietrich, dmd, dr med dent, md, dr med, mph

 

Abstract: Purpose: To evaluate the survival of glass fiber reinforced composite post (GFP) restorations and to identify risk factors for restoration failure. Methods: GFPs of three consecutively placed post systems, two tapered and one parallel-sided, were adhesively luted and the core was built with a resin composite. Teeth served as abutment teeth according to the prosthetic treatment plan. 149 GFP in 121 patients (age: 53 ± 15 year; 50 men; 71 women) were followed for 5-79 months (mean ± SD: 50 ± 21 months). Cox proportional hazards models were used to evaluate the association between several clinical variables and the failure rate. Results: After exclusion of endodontic failures (n=3), significantly higher failure rates were found for restorations of anterior teeth compared to posterior teeth (hazard regression (HR): 2.8; 95% confidence interval (CI): 1.4; 5.8; P= 0.004). Restorations in teeth with no proximal contacts compared to at least one proximal contact, single crowns compared to fixed partial dentures and less than two remaining cavity walls had a HR of 2.4 (C.I.: 0.8 – 7.1), 2.4 (CI: 0.6 – 8.7), and 1.5 (C.I.: 0.6 – 3.8), respectively. However, these correlations were not statistically significant (P> 0.05). (Am J Dent 2008;21:267-272).

   

 

*: Dr. Michael Naumann , Department of Prosthodontics and Material Sciences, University of Leipzig, Nürnberger Straße 57, D-04103, Leipzig, Germany. E-*: micha.naumann@ gmx .de