Molar root canal treatment performed by undergraduate dental students; an observational study of procedural errors and student perception.

BACKGROUND: Molar root canal treatment (RCT) is challenging and requires training and specific skills. Rotary instrumentation (RI) reduces the time needed for instrumentation but may increase the risk of certain procedural errors. The aims of this study were to evaluate the quality of molar RCTs provided by undergraduate students, to compare the prevalence of procedural errors following manual and RI, and to assess the students' self-perceived confidence to perform molar RCT without supervision and their preference for either manual or RI. METHODS: Molar RCTs performed by the final year students were evaluated radiographically according to predefined criteria (Appendix 1). The procedural errors, treatment details, and the students' self-perceived confidence to perform molar RCT and their preference for either manual or RI were recorded. Descriptive statistics were performed, and the Chi-squared test was used to detect any statistically significant differences. RESULTS: 60.4% of RCTs were insufficient. RI resulted in more sufficient treatments compared with MI (49% vs. 30.3% respectively. X2: 7.39, p = 0.007), required fewer visits to complete (2.9 vs. 4.6 respectively. X2: 67.23, p < 0.001) and was the preferred technique by 93.1% of students. The most common procedural errors were underextension of the root canal obturation (48.4%), insufficient obturation (45.5%), and improper coronal seal (35.2%) without a significant difference between the two techniques. 26.4% of the participating students reported that they did not feel confident to perform molar RCT without supervision. CONCLUSION: The quality of molar RCT provided by UG students was generally insufficient. RI partially improved the technical quality of RCT compared with MI. UG students need further endodontic training and experience before they can safely and confidently practise molar RCT.

Endocrowns Clinical Performance and Patient Satisfaction: A Randomized Clinical Trial of Three Monolithic Ceramic Restorations.

PURPOSE: The purpose of this randomized, double-blind, clinical trial was to assess the survival of endocrowns made from three different monolithic ceramic materials, and to evaluate patient satisfaction. MATERIALS AND METHODS: Fifty-three patients (sixty root canal treated molar teeth) were enrolled. Teeth were prepared to a flat butt-joint margin and randomly divided between three material groups: lithium disilicate-reinforced glass-ceramic, monolithic zirconia and polymer infiltrated hybrid ceramic. Predefined cementation protocols were used. Clinical assessment using modified United States Public Health Service (USPHS) criteria was carried out after two years by two independent clinicians blinded to the material used. Radiographic examination was conducted to check for the presence of caries, excess cement, and periapical infection. Statistical analysis was performed using the Kruskal Wallis and Wilcoxon signed-rank tests as well as the Kaplan-Meier survival estimate. RESULTS: Forty-eight patients were available for assessment after 2 years (recall rate 90.6%). The overall Kaplan-Meier survival estimate among all groups was 90.9% with no statistically significant difference between the groups (p = 0.17). Three zirconia endocrowns debonded after 9, 10 and 13 months (82.4% survival rate), while 2 hybrid ceramic endocrowns chipped/fractured (89.5% survival rate). Lithium disilicate endocrowns had a 100% survival rate. The Kruskal Wallis test revealed no statistically significant difference between the groups in the USPHS criteria ratings and the radiographic assessment (P>0.05). Patient satisfaction ranged from 82.3% in the zirconia group to 100% in both the lithium disilicate and hybrid ceramic groups. CONCLUSIONS: Endocrowns provide a predictable option for the restoration of endodontically treated molar teeth in the short term. Lithium disilicate-reinforced ceramic had fewer complications and required less intervention compared with zirconia and hybrid ceramics. Long-term follow-up is required to substantiate these study results.

Methodological Quality of Systematic Reviews Relating to Performance of All-Ceramic Implant Abutments, Frameworks, and Restorations.

PURPOSE: To assess the methodological quality of published systematic reviews relating to all ceramic implant frameworks, abutments and restorations. MATERIALS AND METHODS: Published systematic reviews relating to all ceramic implant restorations for single tooth and multiple teeth replacements were retrieved to assess their methodological qualities. Sixteen systematic reviews were included for methodological quality assessment by two independent assessors using AMSTAR-2 critical appraisal tool. Inter-rater agreement was assessed using the weighted Cohen's Kappa statistic. RESULTS: Most systematic reviews included randomized clinical trials and nonrandomized studies of intervention. The majority of included systematic reviews (15 out of 16) scored critically low on quality with more than one critical flaw when assessed using the AMSTAR-2 tool. Most systematic reviews assessed lacked analysis of the effects of the risk of bias and heterogeneity of the included studies. The inter-rater agreement of the independent assessors was substantial (0.63). CONCLUSIONS: Confidence in the evidence presented in these systematic reviews was undermined by their tendency to overlook the effect of risk of bias and heterogeneity in evidence synthesis.

Use of High Performance Polymers as Dental Implant Abutments and Frameworks: A Case Series Report.

Dental implant abutments can be made of different materials including titanium, gold, zirconia, alumina, and polymeric materials. Polyetheretherketone (PEEK) is a high performance thermoplastic polymer that can be used as a dental implant abutment material. It has an elastic modulus comparable to bone and can reduce stress shielding. PEEK is a radiolucent material that can allow better radiographic imaging of peri-implant tissues and can be veneered with composite materials or bonded to ceramics. PEEK is widely used in orthopedic and spinal surgeries, and it possesses mechanical and biological characteristics that encourage its use as dental implant abutments. This article will review the use of PEEK in dentistry and in particular as a dental implant abutment and over implant framework. Clinical reports will be presented to suggest some uses of PEEK materials in implant dentistry.

Direct 3D Printing of Flexible Nasal Prosthesis: Optimized Digital Workflow from Scan to Fit.

A maxillofacial prosthesis is a successful treatment modality to restore missing facial parts. Digital technologies and 3D printing are employed in constructing facial prostheses such as ears; however, their application is still partial, and final prostheses are usually manufactured conventionally using stone molds. This report aims to introduce a complete digital workflow to construct a nasal prosthesis and compare it to the conventional workflow of a patient requiring a nasal prosthesis. A computer tomography scan showing the defect was exported to specialized software to create 3D reconstructions of the patient's face and underlying bone. The nose was digitally designed restoring facial esthetics, anatomy, shape, and skin color. Different skin tones were digitally matched to skin tissues adjacent to the defect area using the Spectromatch system. The design was 3D printed in flexible and colorful material at 16 µm resolution using a 3D printer. External color pigmentations were applied to the nose for optimum esthetics, and the prosthetic nose was sealed in silicone and left to heat polymerize for 15 minutes. The prosthetic nose was retained in place using biomedical adhesive, and the patient was pleased with it. This report proposes a complete digital workflow to directly design and fabricate a prosthetic nose of acceptable esthetics. Such a workflow can lead to enhanced prosthesis reproducibility and acceptability and may become an effective treatment option for treatment of patients with facial defects.

Evaluating Various Preparation Protocols on the Shear Bond Strength of Repaired Composite.

INTRODUCTION: The aim of this study is to evaluate the effect of different combinations of various surface treatments on the shear bond strength (SBS) of repaired composite resin. MATERIALS AND METHODS: A total of 122 composite samples were prepared from Filtek Z350 XT. Samples were light cured and stored for 6 weeks. Surface treatment of old composite was done in five groups: Group I: bur roughening + phosphoric acid etching, group II: bur roughening + hydrofluoric acid etching + silane coupling agent, group II: air abrasion + phosphoric acid etching, group IV: air abrasion + phosphoric acid etching + silane coupling agent, group V: air abrasion + hydrofluoric acid etching + silane coupling agent. Bonding agent was applied to all surface-treated old composites and light cured. The fresh composite resin was bonded to treated surfaces and cured and stored in water at 37°C for 6 weeks. Shear bond strength was measured by a universal testing machine. RESULTS: Shear bond strength values of all groups were not statistically significant except for group V, which showed statistically significant higher SBS than group III. CONCLUSION: Techniques with readily available materials at the clinic can attain similar SBS to more elaborate technique involving potentially hazardous materials.

Shear bond strength of self-adhesive resin cements to base metal alloy.

STATEMENT OF PROBLEM: Many self-adhesive cements have been introduced in the past few years, with little or no data regarding their clinical performance. This study investigated the shear bond strength of some recently introduced self-adhesive resin cements. PURPOSE: The purpose of this study was to evaluate the shear bond strength of self-adhesive and conventional resin-based cements to a base metal alloy. MATERIAL AND METHODS: Four groups (10-12 each) that comprised 3 self-adhesive cements (SmartCem2; RelyX Unicem; seT SDI) and a conventional resin-based cement (RelyX ARC) were tested. Cylindrical cement specimens (diameter, 3 mm; height, 3 mm) were applied to nickel-free base metal alloy (Sheradent) disks with a diameter of 12 mm, and the surface was treated with airborne-particle abrasion of 50 µm aluminum oxide. The metal disks were fixed in brass molds specifically designed for the shear bond test device. Test specimens were incubated at 37°C for 24 hours and then the shear bond was tested with a Zwick Roll testing machine at a 0.8 mm/min cross-head speed. In addition, bond failures were investigated and categorized as adhesive, cohesive, or mixed. Shear bond strengths were calculated by dividing the maximum debonding force over the cross-sectional area of each specimen. One-way ANOVA and the Tukey (honestly significant difference) post hoc test were used to test statistical significant differences among the groups (α=.05). RESULTS: Statistical analysis showed significant differences among different resin cements (F=14.34, P<.001). The highest mean shear bond strength was observed for SmartCem2 (14.18 MPa), and the lowest was reported for seT (3.52 MPa). The observed failure mode in all the materials was adhesive in nature, which occurred at the resin-metal interface. CONCLUSIONS: The early bond strength of self-adhesive resin cements varied significantly among the tested materials. SmartCem2 showed the highest bond strength, which was 4 times the strength observed for seT SDI.

Deep Margin Elevation - A Retrospective Clinical Study.

PURPOSE: The aim of this retrospective study was to assess the short- to mid-term restorative and periodontal outcome of deep margin elevation (DME) performed using resin composite. MATERIALS AND METHODS: Twenty-eight teeth treated with DME and indirect adhesive restorations were followed-up for a mean of 25.4 months (minimum: 12 months). Clinical and radiographic examination assessed the adaptation of the DME material and indirect restorations, presence of recurrent caries or discoloration, periodontal health at DME and non-DME sites, and periapical health. RESULTS: The overall success rate was 96.6%. One tooth showed signs and symptoms of apical pathology after 34 months following DME. No caries, discoloration, or periodontal pockets were detected in any of the treated teeth. DME had no detrimental effect on the gingival/periodontal health or plaque accumulation. There was no correlation between the distance from the DME material to the marginal bone level and pocket depth, gingival inflammation, and plaque accumulation (p > 0.05). CONCLUSION: Deep margin elevation might be considered a safe procedure for teeth with deep subgingival proximal caries in the short- and mid-term.

Multiple lingual cusps trait on mandibular premolars and hypoconulid reduction trait on mandibular first molar in living Jordanian population. Intra- and inter-trait interactions.

The objective was to determine the expression and fluctuating asymmetry of two dental morphological traits in the living Jordanians: The lingual cusp number on the lower premolars (LP1 and LP2) and the hypoconulid (distal cusp) reduction on the lower first molar (LM1). In addition, both intra- trait and inter- trait interactions were analyzed. Three hundred school children (15.5 +/- 0.4 years) were involved. Impressions for the mandibular dental arches were taken, and dental casts were reproduced. The above-mentioned traits were observed. Paired sample t test and nonparametric correlation analysis were used for data analysis. Three-cusped LP1 was found in 11.40 % of the examined students, while the two-cusped LP1 was found in 88.60%. In comparison, the Three-cusped LP2 was found in 61.40% while the two-cusped LP2 was found in 38.60% of the observed subjects. The frequencies of the 4-cusped and 5-cusped LM1 were found to be 8.65% and 91.35%, respectively. Nonparametric correlation analysis revealed positive and statistically significant association between the expression of two lingual cusps on LP1 and on LP2 in both genders (p < 0.01), while there was no significant correlation between expression of two lingual cusps on either LP1 or LP2 and the hypoconulid loss on LM1 in both genders (p > 0.05). Bilateralism was highly significant in the tested traits in both genders (p < 0.001). This finding might be a sign of relatively low environmental stresses experienced by the living Jordanians and/or great ability of its individuals to buffer the adverse effects of such stresses on dental development. This study is a useful addition to the existing literature in that it examines a previously poorly characterized population and assists in placing the contemporary Jordanian population within the current framework of human population groups globally.

Mechanical properties and bonding of maxillofacial silicone elastomer mixed with nano-sized anti-microbials.

OBJECTIVES: The antibacterial efficacy of silicone is improved by impregnating it with antimicrobials such as chlorohexidine and zinc oxide. The purpose of this study was to examine mechanical properties and bonding of maxillofacial silicone elastomer mixed with Zinc Oxide nanoparticles (ZnO-NP), and Chlorohexidine Diacetate Salt (CHX) at three different concentrations (1 %, 3 %, and 5 %). METHODS: Specimens of a silicone elastomer (M511) were prepared and divided into 7 groups. Group 1 was control of no additive. Groups 2-4 included silicone elastomer mixed with ZnO-NP (surface area = 67 m2/g) at 3 different concentrations (by weight %); 1 %, 3 % and 5 %. Groups 5-7 included silicone elastomer mixed with CHX at the same concentrations. Tear and tensile strengths, elongation percentage, modulus of elasticity, and shear bond strength to primed acrylic resin surfaces were evaluated. Data was analyzed with 1-way ANOVA, Bonferroni, and Dunnett's T3 post-hoc tests (P < 0.05). RESULTS: There was significant effect of the additives on the tensile strength, elongation percentage, tear strength, and shear bond strength (P < 0.05). Shear bond strengths ranged from 0.55 to 0.96 MPa. Silicone elastomer mixed with CHX (5 %) resulted in the highest shear bond strength (P < 0.05). Non-linear regressions between tensile strength and ZnO and CHX additives were 0.95 and 0.96 respectively. SIGNIFICANCE: All additives reduced the tensile strength of the silicone. However, CHX at 5 % optimized shear bond strength and thus is proposed in order to fabricate maxillofacial prostheses of sufficient mechanical properties, bonding and antimicrobial activity.

A Cone Beam CT Study on the Correlation between Crestal Bone Loss and Periapical Disease.

The aim of this study was to determine whether the degree of bone loss around teeth can be linked to the loss of vitality of adjacent teeth and periapical disease, which necessitates root canal treatments. Three hundred and twenty-one full maxilla cone-beam computed tomography scans were examined. The parameters investigated included the degree of crestal bone loss in relation to the cementoenamel junction, the presence/absence of apical periodontitis, and the presence/absence of root canal treatments. Out of the 2001 teeth examined, 696 (34.8%) showed evidence of crestal bone loss. The degree of crestal bone loss was classified as mild, moderate, or severe. A significant association (p < 0.001) was found between the presence of crestal bone loss around a tooth and root canal treatment of that tooth. It was found that it is more likely for teeth with crestal bone loss to be root canal treated compared to teeth with existing root canal treatment and healthy crestal bone levels. Furthermore, teeth with buccal or lingual crestal bone loss were significantly associated with a higher rate of periapical disease than teeth without crestal bone loss (p < 0.001). CBCT identified the severity of bone loss on all surfaces of the teeth, and the most common presentation was bone loss to the mid-root level. Teeth with crestal bone loss were significantly more likely to be associated with a higher rate of periapical disease. Teeth with crestal bone loss were more likely to be root treated than teeth with healthy crestal bone levels.

Hypocone reduction and Carabelli's traits in contemporary Jordanians and the association between Carabelli's trait and the dimensions of the maxillary first permanent molar.

The objective of this study is to determine the prevalence of expression and bilateralism of two dental morphological traits in contemporary Jordanians: The hypocone reduction trait on the maxillary second permanent molar and Carabelli's trait on maxillary permanent first and second molars. Furthermore, inter-trait correlation and the relationship of Carabelli's traits with upper first molar dimensions were investigated. Three hundred subjects of school children at their 10th grade and of an average age of 15.5 +/- 0.4 years were involved. Alginate impressions for the maxillary arch were taken, dental casts were reproduced. The selected accurate casts were of 132 male- and 155 female-students. The frequencies of hypocone reduction trait on the maxillary second molar and Carabelli's trait on the maxillary molars were examined. Buccolingual and mesiodistal diameters of the maxillary first molar were measured and recorded. Paired Sample t test and Nonparametric Correlation analysis were used for data analysis. Hypocone reduction trait on the maxillary second molar was found in 29.8% of the examined students. Positive forms of Carabelli's trait on first and second molars were observed in 65.0% and 3.8%, respectively. Nonparametric correlation analysis revealed positive association between Carabelli's trait on first molar and hypocone reduction trait on the maxillary second molar. The presence of Carabelli's trait on first molar was strongly associated with the increase of buccolingual, but not the mesiodistal, diameter. Bilateralism was found highly significant in the tested traits and both genders (p < 0.001). This finding might be a sign of relatively low environmental stresses in the living Jordanian population and/or great ability of its individuals to buffer the adverse effects of such stresses.

Effect of freshly placed core buildup composites on setting of silicon impression materials.

Aim: The aim is to study the effect of freshly placed composite build-ups on setting of additional silicone impression materials. Settings and Design: In vitro - experimental study. Materials and Methods: Three composite materials; Build-It™ F. R™, Filtek™ Bulk Fill flow and Filtek™ Z350 and three light-bodied additional silicone impression materials; Elite HD+, Aquasil LV Ultra and Express™ were used. Cylindrical-shaped specimens were made of each material (diameter 15 mm and height 10 mm). The silicone specimens were brought into contact with the composite specimens, which were either freshly cured (9 groups, n = 90) or cured and then stored in normal saline for 1 week (9 groups, n = 90). Shore A hardness (SAH) scores of silicone surfaces were recorded following the ASTM D2240-5 standards for shore A Durometer testing. Six measurements were made per each silicone surface and medians were calculated. Kruskal-Wallis and Mann-Whitney tests (SPSS v20) were used to check statistical significant differences between all groups and paired comparisons, respectively (P < 0.05). Statistical Analysis Used: Kruskal-Wallis and Mann-Whitney tests. Results: The SAH scores of additional silicones in direct contact with freshly placed composites were significantly less than SAH scores of additional silicones in direct contact with composites specimens aged for 1 week in 7 out of 9 combinations (P < 0.05). Only when Express™ and Elite HD+ were applied over freshly placed Filtek™ Bulk Fill flow, the SAH scores difference was not statistically significant to SAH scores of matching combinations applied after 1 week of composite storage. Conclusions: Freshly placed composite might affect setting of additional silicone impression materials. Dentists should carefully assess final impression on areas of prepared teeth that have received composite fillings recently.

Observance of proper mercury hygiene practices by Jordanian general dental practitioners.

OBJECTIVES: To assess the knowledge and observance of proper mercury hygiene and amalgam waste management (AWM) among Jordanian general dental practitioners (GDPs). SUBJECTS AND METHODS: Interviews were conducted with randomly selected 250 Jordanian GDPs, using a specially designed questionnaire. Out of the total of 250 GDPs, 228 (91.2%) agreed to participate. The questionnaire covered aspects related to professional information and total amalgam contact (TAC) of these practitioners. The second part focused on the degree of awareness of the protocols related to mercury hygiene and safe AWM. RESULTS: Mean TAC was 3.2+/-3.6 hours per week. Of the Jordanian practitioners, 22.6% reported no undergraduate training in amalgam safety measures. Almost a quarter of GDPs did not have proper ventilation in their clinics, around 20-25% did not use protective clothing or eye protection, 5.3% were mixing amalgam manually, and 13.9% used their bare fingers for inserting the freshly mixed amalgam. Most of unused amalgam ends up through the drain or in trash; there are no recycling facilities to be used. CONCLUSIONS: Most Jordanian GDPs do not strictly follow the mercury hygiene and AWM guidelines. Promoting the American Dental Association (ADA) guidelines through undergraduate and postgraduate training will help GDPs acquire proper attitude towards the proper hygiene practices described in these recommendations.

Awareness of the risk of developing medication-related osteonecrosis of the jaw among bisphosphonate users.

OBJECTIVE: In this retrospective observational study, we evaluated awareness among patients using bisphosphonates (BPs) regarding the risk of developing medication-related osteonecrosis of the jaw (MRONJ) and whether they received appropriate dental screening and treatment prior to commencing medication. METHODS: Patients using BPs who attended the endodontics clinic at Jordan University Hospital in 2019 were interviewed using a pre-designed questionnaire. Data were analysed using descriptive statistics and chi-squared tests. RESULTS: In total, 110 patients were interviewed (84 women, 26 men; age 40-78 years). A total of 94 patients were using oral BP and 16 received intravenous (IV) BP. We found that only 12.4% of participants were aware about the risk of MRONJ following BP use, and only one third of them has received information from their prescribing physicians. In total, 5% of participants were referred to a dentist for screening prior to initiating BP treatment. Patients receiving IV BP and those with a university-level education had better awareness about the risk of MRONJ than oral BP users and those with a high school education level. CONCLUSION: Patients' awareness about MRONJ risk was low in our population. Better patient education and collaboration among physicians and dentists are needed prior to starting BP treatment.

Satisfaction of optional pairing in clinical dental training.

PURPOSE: The aim of this study was to investigate the perceived satisfaction of optional pairing in undergraduate clinical dental training of fourth- and fifth-year dental students and newly graduated intern dentists in the subject of conservative dentistry and endodontics. METHODS: Data were collected through a paper-based 2-part questionnaire. The first part was made of 3 questions; gender, undergraduate dental year, and grade point average (GPA). The second part involved 9 questions about assistant student-year level preference, satisfaction of optional pairing and main advantages and disadvantages of pairing. Statistical analysis was performed using descriptive statistics and Chi-square test to investigate any statistically significant differences. RESULTS: A total of 92.4% were satisfied with optional clinical pairing. Satisfied respondents reported most prevalent advantages were speeding things up (88.5%) and helping in transferring instruments and materials (85.6%). Unsatisfied respondents reported the most prevalent disadvantages were like to work independently (56.8%) and the assistant was not always cooperative (32.4%). Students with low grade point averages (GPAs) felt incompetent to work in pairs compared with high GPA students (P = 0.001). Only 32.4% of participants thought that the assistant student should be given an evaluation mark. About 75% of respondents reported that clinical pairing improved their diagnostic skills and treatment planning. CONCLUSIONS: Optional pairing in clinical dental training had a high satisfaction percentage. Allowing students to choose their own assistants may reduce pairing disadvantages and enhance its advantages. Students may gain a mentoring benefit from being encouraged to optionally pair with similar or higher study-year students.

Esthetic outcome of immediately placed and nonfunctionally loaded implants in the anterior maxilla utilizing a definitive abutment: A pilot clinical trial.

BACKGROUND: Immediate dental implants placement and loading utilizing definitive abutments might save time and cost when an esthetic final result is anticipated. The objective of this prospective clinical trial was to evaluate the esthetic outcome of immediate implantation and immediate nonfunctional loading utilizing definitive abutments, with and without bony substitutes filling the peri-implant gap. MATERIALS AND METHODS: In this clinical trial study a total of 11 implants were placed utilizing a flapless immediate post extraction approach in the maxilla (second premolar to second premolar). Atraumatic extraction was performed and implants were immediately placed. The gap was either left without grafting or filled with particulate bone material. Immediate nonfunctional loading was performed utilizing a definitive abutment. The pink esthetic scores (PESs) were assessed preoperatively, at 1- and 2-year follow-up periods. Dental casts were obtained at respective time intervals; scanned, registered, and closest point distances were measured. For all statistical tests, value of P = 0.05 was set as a statistical significance level. RESULTS: The mean of PES at baseline was 9.4 ± 1.69, at 1 year was 9.5 ± 2.07, at 2 years was 10.2 ± 2.75, for the graft group 10.3 ± 2.8, and for nongrafting group was 10.2 ± 2.59. There were no statistically significant differences in PESs at baseline when compared to 1- and 2-year intervals, and for grafting group versus nongrafting group (P = 0.24). Distances between the two time points for all cases were <1 mm in all reference planes. CONCLUSION: Immediate placement and nonfunctional loading utilizing a definitive abutment appear to result in a stable result as far as esthetic outcome and alveolar process sufficiency are concerned.

Phase down of amalgam. Awareness of Minamata convention among Jordanian dentists.

OBJECTIVES: To assess the knowledge of Jordanian dentists toward phase down of dental amalgam as recommended by the Minamata Convention, and their training and competency in placing posterior composites.  Methods: This study was conducted through structured questionnaire interviews with randomly selected cohort of dentists in Jordan between March 2015 and June 2015. Out of 230 dentists who were invited, 196 (85.2%) agreed to participate. Dentists were asked if they know about the Minamata Convention. They were also asked about their training in placement of posterior composite.  Results: Out of the 196 interviewed, only 13.8% know about Minamata Convention and 17% had an undergraduate training in favor of placing composites in posterior teeth. Approximately 50% of those dentists were not trained in using rubber dam when placing posterior composites, while only 38.3% had training in sectional matrix placement. Undergraduate training did not influence (p=0.00) the dentists' decision to remove old amalgam based on patient's demands. Only 28.1% were of the opinion of discontinuing the use of amalgam due to its alleged health and environmental hazards. There was no general agreement on the type of composite, liner, and bonding strategy when placing posterior composites. Conclusion: Dentists are not well informed on the Minamata Convention and the phase down of amalgam. Training in posterior composite placement should be given more room in undergraduate curriculum and continuous dental education.

Bond strength of self-adhesive resin cements to tooth structure.

OBJECTIVES: The aim of this study was to evaluate the strength of the bond between newly introduced self-adhesive resin cements and tooth structures (i.e., enamel and dentin). METHODS: Three self-adhesive cements (SmartCem2, RelyX Unicem, seT SDI) were tested. Cylindrical-shaped cement specimens (diameter, 3 mm; height, 3 mm) were bonded to enamel and dentin. Test specimens were incubated at 37 °C for 24 h. The shear bond strength (SBS) was tested in a Zwick Roll testing machine. Results were analyzed by one-way ANOVA and t-test. Statistically significant differences were defined at the α = 0.05 level. Bond failures were categorized as adhesive, cohesive, or mixed. RESULTS: The SBS values ranged from 3.76 to 6.81 MPa for cements bonded to enamel and from 4.48 to 5.94 MPa for cements bonded to dentin (p > 0.05 between surfaces). There were no statistically significant differences between the SBS values to enamel versus dentin for any given cement type. All cements exhibited adhesive failure at the resin/tooth interface. CONCLUSIONS: Regardless of their clinical simplicity, the self-adhesive resin cements examined in this study exhibit limited bond performance to tooth structures; therefore, these cements must be used with caution.

Technical quality of root canal treatment of posterior teeth after rotary or hand preparation by fifth year undergraduate students, The University of Jordan.

The aim of this study was to investigate the technical quality of root canal treatment provided by the undergraduate students as their first experience in molar endodontics using nickel-titanium (NiTi) files in a crown-down approach compared with stainless steel standard technique. This study was carried out by the fifth year undergraduate students attending peer review sessions as a part of their training programme, using two different questionnaires to assess the overall technical quality and potential problems regarding endodontic complications after root canal preparation with these two techniques. The overall results indicated a statistically significant difference in the performance of the two instrument techniques in difficult cases showing better performance of the NiTi system and mean rotary preparation time (P < 0.001). Under the conditions of this study, novice dental students, using NiTi ProTaper rotary files, were able to prepare root canals faster with more preparation accuracy compared with canals of same teeth prepared with hand instruments.