Aim. To evaluate tooth surface loss (TSL) severity and associated risk factors in a representative sample of Saudi adults. Materials and Methods. Four hundred TSL patients (200 females and 200 males) participated in this...Aim. To evaluate tooth surface loss (TSL) severity and associated risk factors in a representative sample of Saudi adults. Materials and Methods. Four hundred TSL patients (200 females and 200 males) participated in this study. Each patient completed a comprehensive questionnaire interview (using a modified Tooth wear Assessment Questionnaire) and then examined for the severity of TSL (using ordinal scale). Results. Seventy-five percent of participants demonstrated attrition, 90% had erosion, 15% had abrasion, and 95% had more than one type of TSL. The most common risk factors were consumption of acidic food/drinks (78%), parafunctional habits (70%), and unilateral chewing (50%). 77% of participants demonstrated grade 2 TSL. Males demonstrated greater TSL severity (P ≤ 0.05). Age, systemic disease, number of remaining teeth, acidic food/drinks, bruxism/parafunction, biting objects, facial pain/tenderness, sour taste, exposure to dust, unilateral chewing, using dental abrasives, and brushing frequency/technique had significant relationship with TSL severity (P ≤ 0.05). Conclusions. TSL has a multifactorial aetiology. Parafunction, gastrointestinal problems, and diet were the most common aetiological factors reflecting changes to stressful modern life-styles, eating/drinking habits, and behaviours. Gender didn't influence the aetiology of TSL; however males demonstrated more TSL severity. Patients' age had significant correlation to TSL severity.
Introduction. The aim of this study was to investigate the effect of three different types of disinfectant agents on alginate impression material after 5 and 10 minutes. Method and Materials. In this in vitro experimenta...Introduction. The aim of this study was to investigate the effect of three different types of disinfectant agents on alginate impression material after 5 and 10 minutes. Method and Materials. In this in vitro experimental study, 66 circular samples of alginate impression material were contaminated with Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans fungus. Except for control samples, all of them were disinfected with sodium hypochlorite 0.525, Deconex, and Epimax by way of spraying. Afterwards, they were kept in plastic bags with humid rolled cotton for 5 and 10 minutes. The number of colonies was counted after 24 and 48 hours for bacteria and after 72 hours for fungus. Statistical Mann-Whitney test was used for data analysis (α = 0.05). Results. After 5 minutes, Epimax showed the highest disinfection action on Staphylococcus aureus as it completely eradicated the bacteria. The disinfection capacity of different agents can be increased as time elapses except for Pseudomonas aeruginosa which was eradicated completely in both 5 and 10 minutes. Conclusion. This study revealed that alginate can be effectively disinfected by three types of disinfecting agents by spraying method, although Epimax showed the highest disinfection action after 10 minutes compared to other agents.
Aim. To evaluate the antibacterial activity of four endodontic sealers on Enterococcus faecalis by a direct contact test. Material and Methods. Enterococcus faecalis was used as a test organism. Direct contact test which...Aim. To evaluate the antibacterial activity of four endodontic sealers on Enterococcus faecalis by a direct contact test. Material and Methods. Enterococcus faecalis was used as a test organism. Direct contact test which is based on measuring the effect of close contact between test bacteria and tested material on the kinetics of bacterial growth was performed to overcome the disadvantages of agar diffusion test. The sealers tested were zinc oxide eugenol-based sealer, glass-ionomer-based sealer, polydimethyl-siloxane-based sealer, and urethane dimethacrylate resin-based sealer. Data was collected by recording the optical density with the help of a spectrophotometer. Results. The sealers exhibited different inhibitory effects. The results obtained were subjected to statistical analysis by Kruskal Wallis analysis of variance and Dunn's multiple comparison test. Group comparison showed very highly significant difference between the groups. Conclusion. Zinc oxide eugenol-based sealer was the most effective and urethane dimethacrylate resin-based sealer was the least effective against Enterococcus faecalis, whereas glass-ionomer-based and polydimethyl-siloxane-based sealers were effective only for a short period. Inhibition of the bacterial growth is related to the direct contact of the microorganism with the sealer.
Increasing access for citizens to health services, including dental care, is one of the primary targets of the Indonesian Ministry of Health. To assess progress toward this goal, we sought to describe the magnitude of un...Increasing access for citizens to health services, including dental care, is one of the primary targets of the Indonesian Ministry of Health. To assess progress toward this goal, we sought to describe the magnitude of unmet needs for dental care among Indonesians. Secondary data of nationally representative surveys conducted from 2003 to 2007 were analysed to describe the associations between unmet needs for dental care in different demographic groups. In average, 2.28% of the Indonesian population reported perceiving need for dental care and 0.74% reported utilizing dental care. The average of unmet need was 72.04%. Logistic regression analysis indicated that respondents who lived in rural areas, who were uninsured, had higher odds ratios in reporting unmet dental care needs. Perceived need for and utilization of dental care among Indonesians was found to be low. Moreover, the unmet need for dental care is relatively high.
Introduction. In order to minimize the required time to regain esthetic and function, immediately loaded implants were suggested. The aim of this study was to comparatively evaluate the Nisastan and XIve implants using b...Introduction. In order to minimize the required time to regain esthetic and function, immediately loaded implants were suggested. The aim of this study was to comparatively evaluate the Nisastan and XIve implants using biomechanical and histomorphometric tests. Materials and Methods. In this experimental study, 6 Nisastan one-piece immediately loaded screw type implant (OPILS) and 6 Xive implants with 3.4 mm diameter and 11 mm long were used. The implants were immediately loaded with temporary coating. After three months, the torque required to break bone-implant contact was measured and was recorded. All implants were extracted with surrounding bone and histologically were evaluated. The data were inputted into the SPSS 11.5 to run student T-test statistical analyses (α = 0.05). Results. The success rates of both types of implants was 100%, and none of them failed due to mobility or bone loss. The mean removal torque value (RTV) was 142.08 and 40 N/Cm for Xive and Nisastan implants, respectively, and their RTVs showed a significant difference between two mentioned implants (P = 0.004). None of the histomorphometric values showed significant differences between the two implants (P > 0.05). Discussion. both systems have the capability to induce osseointegration under immediate loads but that Xive implants showed higher capability for bone contact.
The aim of this study was to compare the effect of 17% EDTA, 5% maleic acid, and Nd:YAG laser on smear layer removal by SEM. Eighty single-rooted teeth were divided into three groups of 25 according to the final procedur...The aim of this study was to compare the effect of 17% EDTA, 5% maleic acid, and Nd:YAG laser on smear layer removal by SEM. Eighty single-rooted teeth were divided into three groups of 25 according to the final procedure for smear layer removal: irrigation by 17% EDTA or 5% maleic acid or Nd:YAG laser irradiation. The other five teeth was used as control. Roots were sectioned into buccal and lingual parts, and smear layer presence was recorded in the coronal, middle, and apical thirds under SEM. Data were analyzed by Kruskal-Wallis, Mann-Whitney, Friedman, and Wilcoxon tests. There was no significant difference between smear layer removal of 17% EDTA and 5% maleic acid. Nd:YAG laser showed the least effect significantly. The coronal part of samples was significantly cleaner than the middle, and the middle was cleaner than the apical section. 17% EDTA and 5% maleic acid were more effective in smear layer removal compared to Nd:YAG laser.
THE AIM OF THIS STUDY WAS TO IDENTIFY AND COMPARE ANY DIFFERENCES IN THE POSITION OF THE ANTERIOR LIMIT OF THE DENTITION PROVOKED BY THREE DIFFERENT TYPES OF ORTHODONTIC MECHANICS: traditional edgewise, straightwire and...THE AIM OF THIS STUDY WAS TO IDENTIFY AND COMPARE ANY DIFFERENCES IN THE POSITION OF THE ANTERIOR LIMIT OF THE DENTITION PROVOKED BY THREE DIFFERENT TYPES OF ORTHODONTIC MECHANICS: traditional edgewise, straightwire and self-ligating. A sample of 54 patients (selected from a group of 289 patients) possessed a range of Little's Irregularity Index values for the upper and lower dental arches between a minimum of 6.5 and a maximum of 13.5 at T0, and corresponding final values no greater than 2 and hence of minimal irregularity. The 54 patients were subdivided into three groups according to the type of brackets used in their treatment: Group 1 was composed of 24 patients treated using the self-ligating technique, Group 2 of 15 patients treated using a conventional straight-wire technique (Roth) and Group 3 of 15 patients treated using the standard edgewise technique. Cephalometric tracings were performed on laterolateral teleradiography. Group 1 value was found to be nonsignificant, whereas significant labial inclination was noted in Groups 2 and 3 (P < 0.05). A significant labial inclination of the upper incisors was also evidenced in all three sample groups.
Objectives. To evaluate the effect of apical foramen diameter and apical barrier thickness on the sealing ability of mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM) plugs in open apices. Materials and...Objectives. To evaluate the effect of apical foramen diameter and apical barrier thickness on the sealing ability of mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM) plugs in open apices. Materials and Methods. The fluid filtration method was conducted on a total of 136 roots. Samples were randomly divided into two control (n = 8) and four experimental groups (n = 30). Apical foramen diameters measuring 1.1 and 1.7 mm were shaped for groups "1 and 3" and "2 and 4", respectively. In groups 1 and 2 MTA plug and in groups 3 and 4 CEM plug was inserted. The groups were further divided into subgroups according to the thickness of the apical plugs (3- or 5-mm). Microleakage was measured at 1, 7, and 30 days. Results. Mixed ANOVA test showed that the microleakage in groups 1 and 3 as well as all 5-mm plug subgroups were significantly less than groups 2 and 4 (P < 0.05) and 3-mm subgroups (P < 0.05), respectively. Microleakage was significantly lower at 30th day (P < 0.05). Conclusions. Reducing canal diameter or increasing apical plug thickness and the time interval increases the sealing ability of apical barriers. Furthermore, in comparison to MTA, CEM plugs demonstrated superior sealing ability.
Objective. The aim of this cross-sectional study was to investigate the prevalence of dental anomalies that could be a cause of malocclusion in the western region of Saudi Arabia. Materials and Methods. A retrospective s...Objective. The aim of this cross-sectional study was to investigate the prevalence of dental anomalies that could be a cause of malocclusion in the western region of Saudi Arabia. Materials and Methods. A retrospective study of 878 digital orthopantomograms (OPGs) taken of patients, age ranging between 12 and 30 years, who presented to treatment at the Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia between 2002 and 2011. The OPGs and dental records were reviewed for congenitally missing teeth, supernumerary teeth, impactions, ectopic eruption, transposition, germination, fusion, dilacerations, taurodontism, dens in dent, and any other unusual conditions that can be assessed with OPG. Results. The prevalence of patient that exhibited at least one dental anomaly was 396 (45.1%) patients. The prevalence of congenitally missing teeth was 226 (25.7%), impacted teeth 186 (21.1%), dilacerated teeth 10 (1.1%), supernumerary teeth 3 (0.3%), odontoma 1 (0.1%), and taurodontism was also 1 case (0.1%) of the total radiographs reviewed. Conclusions. Congenitally missing teeth were found to be the most prevalent anomaly (25.7%), and the second frequent anomaly was impacted teeth (21.1%), whereas root dilacerations, supernumerary teeth, and taurodontism were the least frequent anomalies (1.1%, 0.3% and 0.1%, resp.).
Objectives. The primary objectives of this retrospective study were first to compare the upper and lower pharyngeal airway spaces between orthodontic patients with and without maxillary constriction and second to evaluat...Objectives. The primary objectives of this retrospective study were first to compare the upper and lower pharyngeal airway spaces between orthodontic patients with and without maxillary constriction and second to evaluate the effect of rapid maxillary expansion (RME) on these airway spaces. A secondary objective was to compare the mode of breathing between groups. Materials and Methods. The experimental (RME) group consisted of 30 patients (mean age, 14.2 ± 1.3 years, 16 boys and 14 girls) with maxillary constriction who were treated with hyrax-type RME. The control group comprised the records of age- and gender matched patients (mean age, 13.8 ± 1.5 years, 16 boys and 14 girls) with no maxillary constriction but requiring nonextraction comprehensive orthodontic treatment. Cephalometric measurements in the sagittal dimension of upper and lower airway spaces for the initial and final records were recorded. Mode of breathing and length of treatment were also compared. Results. The sagittal dimension of the upper airway increased significantly in the RME group (mean = 1.3 mm) compared to the control group (mean = 0.5 mm), P = 0.016. However, there was no significant difference in the lower pharyngeal airway measurement between the RME group (mean = 0.2) and the control group (mean = 0.4), P = 0.30. There was no significant difference with respect to mode of breathing between the two groups (P = 0.79). Conclusion. Rapid maxillary expansion (RME) during orthodontic treatment may have a positive effect on the upper pharyngeal airway, with no significant change on the lower pharyngeal airway.
Intracystic fluid was aseptically collected from 11 patients with postoperative maxillary cyst (POMC), and DNA was extracted from the POMC fluid. Bacterial species were identified by sequencing after cloning of approxima...Intracystic fluid was aseptically collected from 11 patients with postoperative maxillary cyst (POMC), and DNA was extracted from the POMC fluid. Bacterial species were identified by sequencing after cloning of approximately 580 bp of the 16S rRNA gene. Identification of pathogenic bacteria was also performed by culture methods. The phylogenetic identity was determined by sequencing 517-596 bp in each of the 1139 16S rRNA gene clones. A total of 1114 clones were classified while the remaining 25 clones were unclassified. A total of 103 bacterial species belonging to 42 genera were identified in POMC fluid samples by 16S rRNA gene analysis. Species of Prevotella (91%), Neisseria (73%), Fusobacterium (73%), Porphyromonas (73%), and Propionibacterium (73%) were found to be highly prevalent in all patients. Streptococcus mitis (64%), Fusobacterium nucleatum (55%), Propionibacterium acnes (55%), Staphylococcus capitis (55%), and Streptococcus salivarius (55%) were detected in more than 6 of the 11 patients. The results obtained by the culture method were different from those obtained by 16S rRNA gene analysis, but both approaches may be necessary for the identification of pathogens, especially of bacteria that are difficult to detect by culture methods, and the development of rational treatments for patients with POMC.
The aim of the study was to assess the pattern of malocclusion in different ethnic group of Mauritian population visiting the Orthodontic Department at Mauras College of Dentistry and Hospital, Republic of Mauritius. The...The aim of the study was to assess the pattern of malocclusion in different ethnic group of Mauritian population visiting the Orthodontic Department at Mauras College of Dentistry and Hospital, Republic of Mauritius. The study population comprised of 624 patients who visited the orthodontic department during 2010. The clinical examination was conducted by a well-calibrated orthodontist. The data were recorded in the case sheets and was analyzed for presence of angles class I, class II, and class III malocclusion in both male and female patients of Asian, African, Caucasian, and Chinese ethnicity aged 5-55 years. Malocclusion was found to be high in females compared to males. 414 patients (150 male + 264 female) presented with class I, 182 patients (52 male + 130 female) presented with class II, and 28 patients (12 male + 16 female) presented with class III. Asian ethnic group were more affected and patient seeking orthodontic treatment was high in 11-15 years age group.
A variety of suture materials are available for primary wound closure following oral surgical procedures. The aim was to review the tissue reactions to the various suture materials used in oral surgical interventions. Da...A variety of suture materials are available for primary wound closure following oral surgical procedures. The aim was to review the tissue reactions to the various suture materials used in oral surgical interventions. Databases were searched using the following keywords: cotton, nylon, polyglecaprone 25, polytetrafluoroethylene (ePTFE), Polyglactin 910, polyglycolic acid (PGA), polylactic acid, silk, surgery, suture, and tissue reaction. Articles published only in English language were included. Seventeen studies were included. Two studies reported that polyglecaprone 25 had positive effects on wound-healing as compared to silk. Six studies reported that silk elicits more intense tissue inflammatory response and delayed wound healing as compared to other suture materials (including ePTFE, polyglecaprone-25, PGA, and nylon). Polyglactin 910 sutures were associated with the development of stitch abscess in one clinical study. Eight studies reported that tissue reactions are minimal with nylon sutures. Tissue reactions to suture materials used for oral surgical interventions may vary depending on the surface properties and bacterial adherence properties of the material.
Introduction. Sealing abilities of two self-etch adhesives were evaluated after two aging processes: storage in water and thermocycling. Materials and Methods. Cl V cavities were prepared on the buccal and lingual aspect...Introduction. Sealing abilities of two self-etch adhesives were evaluated after two aging processes: storage in water and thermocycling. Materials and Methods. Cl V cavities were prepared on the buccal and lingual aspects of 48 human premolars, with cervical margins 1 mm below the CEJ. Clearfil Protect Bond (CPB) and BeautiBond (BB) (two-step and one-step self-etch adhesives, resp.) were applied, each to half of the cavities and restored with composite resin. Each group was randomly subdivided into 4 subgroups (n = 12) and evaluated for dye penetration after 24 hours, after 3000 thermocycling rounds, after a 6-month water storage, and after 3000 thermocycling rounds plus 6-month water storage, respectively. Data was analyzed using SPSS 11.5 and Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Results. There were no significant differences in enamel and dentin microleakage between the adhesives (P = 0.683; P = 0.154). Furthermore, no significant differences were observed in enamel microleakage of each one of CPB and BB (P = 0.061 and P = 0.318, resp.). However, significant decrease was observed in subgroups 3 and 4 (P = 0.001) for CPB dentinal margins. Conclusion. In this study, limited aging procedures had no influence on marginal integrity of composite resin restorations bonded with self-etch adhesives of CPB and BB. Furthermore, CPB dentinal sealing improved after aging.
Purpose. To evaluate the histopathological condition of the pulp in teeth with different levels of chronic periodontitis in humans. Methods. Twenty-five single-root nondecayed teeth were divided into three groups as foll...Purpose. To evaluate the histopathological condition of the pulp in teeth with different levels of chronic periodontitis in humans. Methods. Twenty-five single-root nondecayed teeth were divided into three groups as follows: group 1, clinical attachment level (CAL) 3 to 4 mm and alveolar bone loss (BL) from 4 to 6 mm without reaching the tooth apex; group 2, CAL ≥ 5 mm and BL > 6 mm without reaching the tooth apex; group 3, CAL ≥ 5 mm and BL > 6 mm up to the tooth apex. Histological analyses were accomplished after laboratorial processing. Results. The mean of CAL was 3.2 ± 0.7 mm in group 1, 7.6 ± 2.0 mm in group 2, and 12.1 ± 2.8 mm in group 3, while for BL it was 4.8 ± 0.9 mm, 7.6 ± 2.2 mm, and 11.9 ± 2.1 mm, respectively. Histopathological data in the pulpal chambers were similar among the three groups showing normal aspects, and, the radicular pulps showed variable levels of reactive dentin, fibrosis, dystrophic mineralizations, atrophy, and mononuclear inflammatory infiltrate. Conclusions. Gradual progression of the chronic periodontitis led to changes in the histopathological aspects of the radicular pulp with progressive involvement.
Purpose. The aim of the present study was to evaluate the clinical response of the pulp in teeth with chronic periodontitis. Methods. Consecutive patients who had been admitted to the Clinics of Periodontology and fulfil...Purpose. The aim of the present study was to evaluate the clinical response of the pulp in teeth with chronic periodontitis. Methods. Consecutive patients who had been admitted to the Clinics of Periodontology and fulfilled the criteria of inclusion were enrolled from January to December 2007. Ninety-eight single-root teeth from 27 patients with chronic periodontitis were evaluated clinically with regard to clinical attachment level (CAL), probing depth (PD), and gingival recession (REC). After periodontal measurements, Pulpal Sensitivity (PS) was evaluated with the use of a cooling stimulus test. Data was analyzed with Student's t test and contingency C coefficient. Results. Teeth that responded positively to PS test presented lower values of CAL (7.8 ± 2.8 mm), PD (5.0 ± 2.3 mm), and REC (2.8 ± 1.8 mm) in comparison to those that responded negatively (CAL = 12.0 ± 2.2 mm; PD = 7.9 ± 1.6 mm; REC = 4.1 ± 2.4 mm) (P < 0.01, Student's t test). In addition, significant correlations were observed between PS and periodontal parameters. Conclusions. Within the limits of this study, it could be suggested that the progression of periodontitis may significantly influence the negative pulpal response.
Background. In India there have been limited number of studies on periodontal status among drug addicts, and thus this study aims to assess the Oral hygiene and periodontal status in substance abusers and compare it with...Background. In India there have been limited number of studies on periodontal status among drug addicts, and thus this study aims to assess the Oral hygiene and periodontal status in substance abusers and compare it with non-substance abusers. Methods. A comparative study was conducted to assess the periodontal status in substance abusers. Non-substance abusers were procured from the general population of Bangalore. From the control group 250 non-substance abusers were age and sex matched with the study population of substance abusers. The oral hygiene and periodontal condition of all subjects was assessed using Oral hygiene index- simplified (OHI-S), Russell's periodontal indices and Gingival bleeding index. Results. The mean of OHI-S and Periodontal Index (Russell's Index) scores were higher (2.70 and 3.68, resp.) in substance abusers than the control group (2.45 and 2.59, resp.). The mean Gingival bleeding score was lower (9.69) in substance abusers than the control group (22.7) and found to be statistically significant. A positive correlation found between OHI-S and Russell's periodontal index whereas negative correlation was found between OHI-S and Gingival bleeding in substance abusers. Conclusions. Though the oral hygiene was fair, more periodontal destruction and less of gingival bleeding were observed in substance abusers as compared to control group.
The objective of this paper was to assess the effects of school-based fluoride mouthrinsing (S-FMR: weekly using 0.2% NaF solution) in two groups of school children with different periods of exposure to S-FMR in elementa...The objective of this paper was to assess the effects of school-based fluoride mouthrinsing (S-FMR: weekly using 0.2% NaF solution) in two groups of school children with different periods of exposure to S-FMR in elementary school. Subjects were the S-FMR group consisted of 599 children, participated for six years. The control group consisted of 282 children, participated for less than one year in the sixth year of elementary school. From the results of the present survey, the caries reduction rate of S-FMR in the permanent teeth was 36.6% for DMFT and 42.8% for DMFS, and person rates with DMF, DMFT, DMFS, and CO (questionable caries under observation) were inhibited in both boys and girls. Girls in the control group showed clearly higher values for all parameters of dental caries because of earlier teeth eruption; however, no gender differences were observed in the S-FMR group. As caries prevalence in the first molars accounted for about 85% regardless of participation to S-FMR, and first molar caries were more common in the mandible than in the maxilla, consideration should be given to preventive measures against pit-and-fissure-caries in addition to S-FMR.
Porphyromonas gingivalis (Pg) fimbriae, in addition to lipopolysaccharide, are involved in the pathogenesis of periodontal disease. At the same time, bioactive compounds such as fibronectin (FN) and melatonin in saliva a...Porphyromonas gingivalis (Pg) fimbriae, in addition to lipopolysaccharide, are involved in the pathogenesis of periodontal disease. At the same time, bioactive compounds such as fibronectin (FN) and melatonin in saliva and gingival crevicular fluid have been reported to exert a preventive effect against periodontitis. Here, we review current knowledge regarding the potent inhibitory effects of FN and melatonin against Pg fimbria-induced induction of proinflammatory cytokines, cyclooxygenase-2 (COX-2) expression, and NF-kappa B activation in mouse macrophages and discuss their possible clinical application for prevention of periodontal diseases induced by oral bacteria.
The aim of the study was to investigate the effect of bleaching on the colouration of tooth enamel and shear bond strength of orthodontic ceramic brackets based upon current whitening practice. The bleaching and bonding...The aim of the study was to investigate the effect of bleaching on the colouration of tooth enamel and shear bond strength of orthodontic ceramic brackets based upon current whitening practice. The bleaching and bonding techniques were performed on extracted bovine teeth for the investigation of their colorimetric spectrum and the adhesive bond strength on surface enamel. One group was designated as the control group with no pre-treatment. Another group was treated with a 45% hydrogen peroxide solution prior to bonding. The difference in colour was expressed as the Euclidian distance ΔE. The resulting shear bond strength was analyzed and evaluated by scores of Adhesion Remnant Index. Statistical analysis was performed using the Kruskall-Wallis and post-hoc test. The colorimetric analysis revealed statistically significant differences between original and bleached as well as bleached and debonded teeth setting off a blue colour shift. Furthermore, statistically there was no significant difference noted in bonding strength between non-treated surfaces and those treated with peroxide. It can be concluded that peroxide pre-treatment does result in colour differences of teeth. Bonding and debonding procedures seem to have no statistically significant influence on the enamel colour using current materials.