Journal of Dental Sciences - Articles in Press

Enhanced cisplatin resistance in oral-cancer stem-like cells is correlated with upregulation of excision-repair cross-complementation group 1 - Corrected Proof

2012-05-21

Abstract: Background/purpose: Oral squamous cell carcinoma (OSCC) is a prevalent cancer worldwide. Recent data suggest that a subpopulation of cancer cells, termed cancer stem cells (CSCs), is capable of initiating, maintaining, and expanding the growth of tumors. Importantly, CSCs confer chemo- and radioresistance. Cisplatin is the most widely used chemotherapeutic agent, and chemoresistance to cisplatin is one of the major causes of tumor recurrence and metastasis with OSCC. However, the role of oral-cancer stem-like cells (OC-SLCs) in the chemoresistance of OSCC has not determined. The aim of this study was to investigate a key player of chemoresistance in OC-SLCs.Materials and methods: OC-SLCs were isolated through sphere formation by cultivating the OC2 cell line in defined serum-free medium. Differential expression profiles of cell-surface stemness markers between enriched OC-SLCs and parental OSCC cells were elucidated by flow cytometry. Expression of excision repair cross-complementation group 1 (ERCC1) by OC-SLCs was examined by an RT-PCR and Western blotting.Results: Initially, significant sphere formation (OC-SLCs) was observed in OC2 cells. Enriched OC-SLCs highly expressed stem-cell surface markers (CD117 and CD133) and the ABC transporter gene (ABCG2). Enhanced chemoresistance to cisplatin was also noted in OC-SLCs. Further, the chemoresistance of OC-SLCs to cisplatin was possibly correlated with ERCC1 upregulation in OC-SLCs.Conclusions: In summary, these results suggest that OC-SLCs may play a vital role in tumor recurrence due to resistance to cisplatin. Additionally, ERCC1 upregulation might be involved in platinum resistance in oral CSCs.

Prevalences of betel nut chewing and cigarette smoking among male prisoners before their imprisonment in Taiwan - Corrected Proof

Man-Line Chen, Kuei-Liang Yang, Hong-Sen Chen, Shu-Feng Shieh, Tien-Yu Shieh — 2012-05-21

Abstract: Background/purpose: Substance abuse is considered prevalent in incarcerated populations; however, consumption of betel nut in this group has not been adequately studied. In the present study, we attempted to elucidate the prevalences of betel nut chewing and cigarette smoking, and determine the relationship between use of the two substances among prisoners before imprisonment in order to increase our understanding of this phenomenon.Materials and methods: In 2000, a self-administered anonymous questionnaire was given to 976 male prisoners who were over 18 years of age and had been sentenced to imprisonment for a total incarnation period of more than 10 years in Kaohsiung Prison, Kaohsiung, Taiwan.Results: The response rate was 60.3% (589/976). Respective prevalences of betel nut chewing and smoking before imprisonment were 73.2% and 90.7%. Results of a cross-sectional analysis showed that dual-substance (betel nut and cigarette) users made up the majority (71.6%) of the study sample, whereas simple smokers and simple chewers comprised 19.0% and 1.5%, respectively. Only 7.8% of participants used neither substance. Smoking generally began 5.07 years before betel nut use. The duration of betel nut chewing was significantly associated with the daily quantity chewed (r=0.212; P<0.01), and a significant relationship was also found between the daily quantity chewed and smoking (r=0.314; P<0.01). Moreover, the daily quantity chewed increased concomitant with the chewing duration and daily quantity smoked.Conclusions: Prevalences of betel nut chewing and smoking are high among male Taiwanese prisoners before imprisonment. The association of use of these two substances among Taiwanese inmates was significant in a time-dependent manner.

Vertical fracture resistance of endodontically treated teeth restored with four sets of obturation and filling materials - Corrected Proof

Mastaneh Javaheri, Ladan Bahmani-Zanjani, Vahid Rakhshan, Maryam Foroozia — 2012-05-17

Abstract: Background/purpose: Various methods were proposed to increase the fracture resistance of endodontically treated teeth. This study comparatively evaluated the fracture resistance of teeth restored with two obturation and two filling systems.Materials and methods: Forty noncarious single-canal premolars underwent MOD and step-back root-canal cavity preparations. They were randomly divided into four groups of 10 teeth each, according to two categories of coronal restoration (amalgam-Panavia F [A] and composite [B]) and obturation (gutta-percha-AH26 [1] and Resilon-Epiphany [2]). These premolars along with 10 intact control teeth were incubated in 100% humidity (37°C) for 1 week, and then were subjected to compressive forces at a 0.5-mm/min crosshead speed to measure fracture loads. Types of fractures (restorable or nonrestorable) were evaluated under 32× magnification.Results: An ANOVA revealed a significant difference among all groups (P=0.000). According to Tukey's honest significant difference test, there were significant differences only between Groups 1B and 1A, and between 2B and 2A (those restored with amalgam compared to those restored with composite). However, an independent-samples t test revealed a significant difference between 1A and 2A as well (gutta-percha-AH26 and Resilon-Epiphany restored with amalgam, P=0.027).Conclusions: Composite-resin restorations may recover significantly more fracture resistance than those bonded with amalgam. Resilon-Epiphany may have slightly but not significantly superior results in terms of fracture resistance.

Effects of three luting agents and cyclic impact loading on shear bond strengths to zirconia with tribochemical treatment - Corrected Proof

Naoko Kawai, Jie Lin, Hidenori Youmaru, Akikazu Shinya, Akiyoshi Shinya — 2012-05-14

Abstract: Background/purpose: The purpose of this study was to investigate the effects of cyclic impact loading on shear bond strengths of three different luting cements to zirconia.Materials and methods: The following cements were used in this study for bonding two zirconia blocks that were tribochemically silica-coated with the Rocatec system: Super Bond C&B (SB); Panavia Fluoro Cement (PF); and Fuji Luting (FL). Specimens were subsequently subjected to three storage conditions: 106 compressive cyclic impact loading (CL), 106 shear cyclic impact loading (SL), and no cyclic impact loading (Control) in distilled water at 37°C with a mechanical fatigue testing device. Shear bond strength tests were performed with a universal testing machine.Results: Bond strengths of PF+Control (63.6±2.4MPa) and PF+CL (57.2±3.8MPa) were significantly higher than those with SB and FL. There was no significant difference between CL and SL (P>0.05) with SB and FL. The bond strength of the FL resin-modified glass ionomer cement was significantly lower than those with PF and SB. After applying tribochemical treatment, all specimens subjected to cyclic impact loading exhibited cohesive failure in the resin cement.Conclusions: After 106 compressive cyclic impact loading, the highest bond to zirconia was obtained with 10-methacryloxydecyl-dihydrogenphosphate containing a luting system (Panavia Fluoro Cement). After applying tribochemical treatment to zirconia, all cements used in this study survived more than 106 shear or compressive cyclic impact loading at 10kg.

Damage to the root after tooth movement towards a temporary anchorage device: An animal pilot study - Corrected Proof

2012-05-14

Abstract: Background/purpose: Obvious craters are consistently found on roots when the teeth move against the screws of a temporary anchorage device (TAD) in human studies. In order to understand the dynamics of tissue reactions with this contact during orthodontic tooth movement (OTM), an animal experiment was performed.Methods: Two mongrel dogs were used. In the first animal, the teeth were moved towards the screws for 12 weeks, and a 6-week healing period was used. In the second animal, loading was continued for 18 weeks without a healing period.Results: Screws in contact with a root during OTM remained stable. Damage to the roots was indeed present as shallow dents, although this amount of damage was relatively small compared to the width of the root. A few inflammatory cells were detected in the periodontal structures. Once the force of the load was removed, there was little evidence of ongoing resorption.Conclusions: A root moving towards a screw during OTM leads to crater-like damage. When time was allowed for healing, a trace of labeled cementum was found to have repaired the root surface, although a large portion of the concavity was filled in with alveolar bone, and the periodontal ligament space remained constant. A root moving against a screw produced excessive tipping. To avoid deviation from the predicted biomechanics and damage to the root, extra caution should be used to ensure the best benefits for patients when TADs are used interdentally for distalization of the dentition during orthodontic treatment.

Evaluation of the surface roughness of a standard abraded dental porcelain following different polishing techniques - Corrected Proof

Haroon Rashid — 2012-05-14

Abstract: Background/purpose: To evaluate the surface roughness of the metal ceramic VITA VMK 95, a standard dental porcelain used for metal-ceramic restorations.Materials and methods: Glazed ceramic blocks of VITA VMK 95 were grinded using a rugby-shaped diamond bur in order to mimic the chairside-adjustment process and then polished using two polishing techniques. Polishing was performed using Sof-Lex discs or Sof-Lex discs followed by polishing with brushes and a prophylaxis paste. To evaluate the surface roughness, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) using the Genie digital image capture system were performed. Average roughness (Ra), root mean square roughness (Rq), valley roughness (Rv), and peak roughness (Rp) were evaluated using CLSM.Results: The results were analyzed using one-way analysis of variance with the post hoc Tukey test at a significance level of 5%. There were statistically significant differences between the rough group and the two polished groups (P<0.05). There was no statistically significant difference between the two polished groups (P>0.05).Conclusions: Although the Sof-Lex discs significantly reduced the surface roughness, their use with the prophylaxis paste and polishing brushes did not cause a further reduction in the surface roughness.

Caries experience among adolescents in southeast Italy - Corrected Proof

2012-05-07

Abstract: Background/purpose: According to WHO recommendations, 12-year-olds are considered an important target group for evaluating the level of dental caries among children with permanent teeth, and are often chosen for international comparisons. The aim of the present study was to evaluate the current oral health status of 12-year-old children in southeast Italy, stratified by gender and residential area.Materials and methods: The survey was conducted on 431 children enrolled by multistage cluster sampling. A dental caries experience index (decayed, missing, and filled permanent teeth; DMFT) was recorded at schools by a team of examiners trained at the start of the study. Statistical analyses by Chi-square, Fisher's exact, and Wilcoxon tests were performed using SAS version 9.1 software for PCs. We applied the Zero-Inflated Negative Binomial regression model in the STATA package.Results: Caries prevalence was recorded in 38.3% of the sample. Estimated means and 95% confidence intervals of the DMFT index by gender were: 1.15 (0.91–1.39) for males, 1.26 (1.02–1.5) for females, and 1.21 (1.03–1.39) for the total sample. The D component of the index was dominant. The mean number of caries found in southeast Italy was significantly higher than the national mean (t=3.125, P=0.002), but significantly lower than the mean for south Italy (t=−2.125, P=0.03). Results of the regression model showed that only the mother and father's nationality and educational level contributed to the DMFT.Conclusions: The oral health situation of 12-year-old children from southeast Italy seems to be in line with that in other Western European countries.

Effects of applying glutaraldehyde-containing desensitizer formulations on reducing dentin permeability - Corrected Proof

2012-05-07

Abstract: Background/purpose: The efficacy of dentin-desensitizing agents is commonly evaluated in clinical studies by measuring patients’ pain response upon stimulation. Although indispensable, such trials are time-consuming, and the results depend on an individual’s subjective pain rating. Therefore, in vitro efficacy screening prior to clinical testing is highly desirable. The objective of this study was to investigate in vitro dentin permeability of two glutaraldehyde-containing desensitizer formulations after different modes and times of application.Materials and methods: Coronal tooth slices, 1.3mm thick, were dissected from 60 freshly extracted third molars. Specimens were treated with EDTA to remove the cutting smear. The dentin disks were clamped in a split chamber device to determine the baseline permeability under a liquid pressure of 2.5kPa for 2 minutes and 13kPa for 1 minute, to record liquid flow through the dentin using a photochemical method. Slices were soaked in a 2% albumin solution and reevaluated under the same pressure cycles prior to active or passive application for 15, 30, or 60 seconds of either Gluma Desensitizer or Gluma PowerGel (GDP) (Heraeus Kulzer, Hanau, Germany) and then reevaluated. Dentin-disk permeability was determined as the area under the photo signal output voltage line during the pressurizing period (mV s). The statistical data analysis used a Kruskal-Wallis ANOVA and Mann-Whitney post-hoc test with the significance level set to 5%.Results: Permeability at the baseline and after albumin soaking did not significantly differ. For both desensitizing compounds, 30 and 60 seconds of active and passive applications resulted in significantly reduced dentin permeability. After the 15 second application, only the actively treated samples with GDP showed a significant reduction in permeability.Conclusions: The liquid and the gel desensitizing agents both significantly reduced dentin permeability. The obvious advantage of a gel formulation is the controlled application, limited to the hypersensitive tooth area, thus avoiding inadvertent contact with adjacent gingival tissues.

Fracture resistance of endodontically treated teeth restored with or without post systems - Corrected Proof

Şükran Bolay, Elif Öztürk, Behram Tuncel, Atilla Ertan — 2012-05-07

Abstract: Background/purpose: The aim of this study was to determine and compare the fracture resistance of endodontically treated teeth restored with or without posts.Materials and methods: Undamaged, extracted human premolar teeth (48 in total) were randomly divided into four groups of 12 each. Clinical crowns of the teeth were cut 3mm coronal to the cementoenamel junction. Root canals were enlarged using rotary canal instruments (Dentsply) and filled with gutta-percha (Dentsply) as well as a sealer (AH 26, De Trey). In all groups, gutta-percha was removed, and the post space was prepared using tapered drills (FRC Postec post kit, Ivoclar Vivadent). The first group of fiber-reinforced composite posts (FRC Postec Plus, Ivoclar Vivadent) and the second group of Ever Stick posts (Stick Tech) were luted into the root canals using dual curing resin cement (Variolink II, Ivoclar Vivadent). In the third group, post spaces were filled using a hybrid resin composite (Tetric Evo Ceram, Ivoclar Vivadent). The fourth group served as a control with direct resin composite core reconstruction formed without a post. Composite cores were constructed with a hybrid resin composite (Tetric Evo Ceram, Ivoclar Vivadent) in all groups. Fracture loading was accomplished using an universal testing machine at a crosshead speed of 1mm/min in compression mode.Results: There were no statistically significant differences between the fracture resistance values for the four experimental groups (P>0.05).Conclusions: Fiber-reinforced posts can be used as a core material in endodontically treated teeth as well as composite core reconstructions.

Accidental swallowing of the head of a dental mirror: Report of a rare case - Corrected Proof

Murat Oncel, Burhan Apiliogullari, Funda Kont Cobankara, Seza Apiliogullari — 2012-05-07

Abstract: Foreign body ingestion/aspiration episodes are potential complications in all branches of dentistry. We report a case of swallowed head of dental mirror found in the esophagus. In this unusual case, a 26-year-old male who was anxious because of excessive pain accidentally swallowed the head of the dental mirror during examination. Given the absence of immediate clinical complications, the patient underwent a chest radiograph. The head of dental mirror was located in the middle third of the esophagus and was later removed by rigid esophagoscopy. To our knowledge, this is the first documented case of a swallowed head of dental mirror found in the esophagus. In addition to the clinical repercussions, this paper also discusses management strategies for patients who have accidentally swallowed components of dental instruments.

Fifteen years of follow-up of a removable prosthetic design to maintain two remaining molars in a patient with mandibular reconstruction - Corrected Proof

Ming-Lun Hsu, Jacqueline Chia-Hsuan Wu, Ling-Ming Yu — 2012-05-07

Abstract: This clinical report describes a long-term prosthetic solution for a patient who had undergone mandibular reconstruction with a fibular graft, leaving only two right molars. The only retention device for the removable prosthesis design included a telescoping system with an O-ring application, but without fibula graft involvement. This prosthesis design was motivated by the altered bony and muscular architecture resulting in an increased maxillomandibular space and thick soft tissue in the denture-bearing area. This case demonstrates that appropriate denture design, consistent recall maintenance, and oral hygiene motivation minimized periodontal destruction and maximized prosthetic use for the patient despite the unfavorable loading conditions.

Torus palatinus in end-stage renal disease patients receiving peritoneal dialysis: Does renal osteodystrophy play a role? - Corrected Proof

2012-04-30

Abstract: Background: Our aim was to investigate the prevalence, size, locations, and shapes of torus palatinus (TP) in end-stage renal disease (ESRD) patients receiving peritoneal dialysis (PD) in order to analyze the relationship between the TP size and duration of PD.Materials and methods: During 2007, 91 ESRD patients receiving PD were studied using dental examinations at our outpatient clinic.Results: The prevalence of TP was 41.7% (n=38). Most cases of TP were < 2cm in size (81.6%) and spindle-shaped (78.9%). The duration of PD was statistically higher in patients with TP size > 2cm (6.8±3.6 years) than patients with TP size of < 2cm (3.5±2.6 years).Conclusions: The higher prevalence of TP and different TP shape (spindle) in comparison with our previous study and the significant relationship between duration of PD and TP size might be due to an underlying disorder, such as renal osteodystrophy.

Comparison of conventional and L-extension deltopectoral flaps in head-and-neck reconstructions - Corrected Proof

Chun-Ming Chen, Huey-Er Lee, Ju-Hui Wu, Pei-Chen Lu, Je-Kang Du, Kun-Tsung Lee — 2012-04-30

Abstract: Background/purpose: In this study, we investigated outcomes for conventional deltopectoral (DP) flaps and L-extension deltopectoral (L-DP) flaps in head-and-neck reconstructions.Materials and methods: Twenty-three conventional DP flaps and 10 L-DP flaps were created in 33 patients. The latter flaps were applied with no delay. The flaps were folded only in the L-DP-flap group. Seven of 10 L-DP flaps were folded to become bilayered flaps in order to repair full-thickness defects. Flap success rates and complication rates were compared between the conventional DP-flap and L-DP-flap groups.Results: Success rates were 91.3% in the DP-flap group and 90% in the L-DP-flap group. Overall complication rates of the transferred flaps were 30.4% and 40% for DP and L-DP flaps, respectively. Complications in the two groups were analyzed by a Chi-square test, and no significant differences were found.Conclusions: Although the DP flap is considered to be the “aged workhorse” in contemporary head-and-neck reconstructions, it was shown to be a beneficial regional flap with a dependable pedicle and easy technique. The L-DP flap is of value particularly when used to treat full-thickness defects of the head-and-neck.

Effects of eluted components from 4-META/MMA-TBB adhesive resin sealer on osteoblastic cell proliferation - Corrected Proof

2012-04-27

Abstract: Background/purpose: Adhesive resin sealer systems are applied to seal root-canal systems more effectively through the formation of a resin impregnation layer. The purpose of this study was to investigate the effects of eluted components of the adhesive, Super-Bond sealer (SBS), on the proliferation of osteoblastic cells in vitro.Materials and methods: The standard powder:liquid ratio according to the manufacturer's instructions was used to produce a cylindrical block of SBS (5mm in diameter, 10mm long) for this elution study. The resin block was placed on a 100-mm culture dish. Osteoblastic cells were seeded at a density of 4×106 in α-minimum essential medium containing 10% fetal bovine serum and cultured in a humidified incubator. After 3 days of culture with or without SBS, cells were retrieved and lysed according to the manufacturer's instructions. The cellular events induced by the eluted components from SBS were analyzed using an antibody assay for mitogen-activated protein kinases (MAPKs) and a 3-(4,5-dimethylthyazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore, the concentration of boron, a component of the catalyst, tri-n-butyl borane (TBB), was analyzed using inductively coupled plasma optical emission spectrometry.Results: Expression of MAPKs increased after SBS application. The MTT assay indicated that TBB, one of the components of SBS, accelerated the proliferation of osteoblastic cells. Values of boron were 1.66±0.37 and 1.74±0.30ppm in cells cultured with and without FBS, respectively.Conclusions: The eluted components from SBS can increase the expression of some MAPKs related to osteoblastic cell proliferation and differentiation in vitro. Both the elution experiment and treatment of cell culture with SBS components indicated that the boron originating from TBB is likely to be responsible for activation of the proliferation of osteoblastic cells.

Evaluation of caries risk in a young adult population using a computer-based risk assessment model (Cariogram) - Corrected Proof

Ilkay Peker, Tandogan Mangal, Hulya Erten, Gulcin Alp, Emre Avci, Gulcin Akca — 2012-04-23

Abstract: Background/purpose: Cariogram is a software program which was recently developed for the practical application of caries-risk assessment. The purpose of this study was to evaluate the relationships between caries risk and different variables of Cariogram in a young adult population.Materials and methods: This study included 90 volunteers (49 females and 41 males) aged 19–25 years. Systemic diseases, diet frequency, fluoride programs, and the decayed, missing, and filled teeth (DMFT), decayed, missing, and filled surfaces (DMFS), and plaque indices were recorded by clinic and radiographic examinations. The saliva secretion rate, and Streptococcus mutans and Lactobacillus counts were determined by saliva sampling.Results: Statistically significant correlations were found between the caries risk determined by Cariogram and the past caries experience (DMFT and DMFS indices), fluoride programs, and S. mutans and Lactobacillus counts in the saliva. The results of a linear regression analysis showed that the most important factors for caries risk were the past caries experience, diet frequency, fluoride program, saliva secretion rate, and S. mutans and Lactobacillus counts.Conclusions: According to the results of this study, the most important factors for caries risk were the past caries experience, fluoride programs, and S. mutans and Lactobacillus counts in saliva. Cariogram is a helpful method for dentists in clinical practice to assess caries risk, and it can be used as a didactic tool for patient education and motivation.

Outcomes of intentionally replanted molars according to preoperative locations of periapical lesions and the teeth - Corrected Proof

WooCheol Lee, Won-Jun Shon, Seung-Ho Baek, Kee-Yeon Kum, Hyeon-Cheol Kim — 2012-04-23

Abstract: Background/purpose: The aims of this retrospective study were to assess the influence of preoperative periapical lesions on the healing of intentionally replanted teeth and compare outcomes of intentional replantation (IR) between maxillary and mandibular molars.Materials and methods: In this study, we retrospectively analyzed 79 cases in whom the IR procedure was used. The outcome of treatment was classified clinically and radiographically as either success or failure.Results: The overall success rate of the reviewed IR procedures was 68.7%. The success rate of IR with mandibular molars (78.0%) was significantly higher than that with maxillary molars (41.2%). There was no significant difference between success rates of IR for teeth with and without preoperative periapical lesions (66.7% vs. 72.0%, respectively).Conclusions: Within the limitations of this study, IR of mandibular molars seemed to provide a higher success rate than that for maxillary molars, regardless of the presence of preoperative periapical lesions.

WITHDRAWN: Treatment of traumatized maxillary central incisors - Corrected Proof

Jun Kuo, Yng-Tzer Joseph Lin — 2011-05-03

The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:<10.1016/j.jds.2011.09.009>. The duplicate article has therefore been withdrawn.