Avicenna Journal of Dental Research
Volume:4 Issue: 1, Jan 2012

The interest of dental research in metal-free restorations has been rising in the last 20 years following the introduction of innovative all-ceramic materials in the daily practice. In particular, high-strength ceramics and related CAD/CAM techniques have widely increased the clinical indications of metal-free restorations, showing more favorable mechanical characteristics compared to the early ceramic materials. Zirconia has been recently introduced in prosthetic dentistry for the fabrication of crowns and fixed partial dentures, in combination with CAD/CAM techniques. The aim of the present paper was to provide a brief review on some aspects of zirconia dental restorations with focus on recent scientific researches.

Statement of the Problem: In recent decades, immediate implant placement has been proposed to eliminate undesirable consequences of conventional methods of delayed placement. In addition, because of the nature of this treatment method, a higher risk of complications such as infection and also higher failures rates may be expected. The aim of this study was to compare clinical outcomes of conventional and immediate placement of dental implants in a group of Iranian war-wounded subjects. In a cross-sectional study, a questionnaire was filled for war-wounded patients referred for dental implants to Ghazi Tabatabaei Clinic in Tehran from March 2000 to March 2007. Finally univariate and then multivariate analyses of clinical outcomes of implantation were carried out. A total of 271 implants, placed in 42 patients, were assessed. In the univariate analysis only associated interventions had a significant effect (P=0.018) while use of grafts (P=0.071), method of implantation (P=0.054) and length of implant (P=0.057) had a tendency toward significant relation with clinical outcomes of implantation. Logistic regression model showed that use of graft and longer implants were independently associated with clinical failure of implantation. In this study with limited follow-up period 3% of implants failed clinically, with a tendency toward higher rates for immediately placed ones. Besides, use of grafts during associated interventions was associated with higher probability of clinical failure which could show that these interventions could even worsen the clinical outcome of implantation. The finding that longer implants had higher rates of failure might be attributed to short follow-up period.

Statement of the Problem: Some studies reveal that the oral cavity acts as a potential reservoir for H. pylori or a possible route of transmission. The aim of this study was to evaluate the association between advanced periodontal diseases and gastrointestinal problems and the effect of oral hygiene on this relationship. This descriptive cross-sectional study was carried out on 71 patients with advanced periodontal disease, referring to Kermanshah Dental School. History of any systemic disease (non-gastrointestinal), alcohol consumption, smoking, addiction and diabetes was considered as exclusion criteria. Patients were divided into two groups: non-gastrointestinal problems and gastrointestinal problems (regurgitation, swelling and peptic ulcers). In addition, these groups were subdivided into three subgroups: no tooth brushing, and brushing once and twice a day. Statistical analysis was carried out using chi-squared and Fisher’s exact tests. Statistical significance was defined at P<0.05. There were 42 patients (59.1%) with gastrointestinal problems. The statistical difference between advanced periodontal diseases and gastrointestinal problems in patients was significant (P<0.05). 81.1% of patients not brushing daily, 68.9% brushing once a day and 13.3% brushing twice a day had gastrointestinal problems, with statistically significant differences (P<0.05). This study revealed that patients with advanced periodontal disease have also more gastrointestinal disorders and tooth brushing twice a day significantly decreased gastrointestinal problems in patients.

Statement of the problem: Addition of metallic nano-particles to composite resins can change their water contact angle. The aim of this study was to evaluate the effect of addition of nano-particles of silver and zinc oxide to composite resins on their water contact angle. This in vitro study was performed on 60 composite resin samples. Nano-silver and nano-zinc oxide were added to composite resin at 0.5% and 1% by weight. SEM-EDX analysis was performed to confirm the homogeneity of the nano-particle distribution. Composite resin discs were made in molds measuring 10 mm in diameter and polished with silicon carbide papers. Water contact angle measurements were performed on 4 points on the surface of each sample, and the mean of the points was reported as the water contact angle of the sample. Two-way ANOVA, followed by the Tukey-HSD test and independent t-test with a significance level of 5%, were used for data analysis. The addition of nano-particles caused a reduction in the contact angle between water and composite resin (P=0.000). The interaction of the type of nano-particle and its concentration on the contact angle was significant (P=0.000). Water contact angle varied depending on the type of nano-particle (P=0.000) and its concentration (P=0.028). Addition of silver and zinc-oxide nano-particles to composite resin reduced the water contact angle of composite resin.

Statement of the Problem: Replacement of missing or lost teeth with dental prostheses supported by dental implants has been accepted and received positive evaluations from patients who have undergone implant treatment. The aim of this study was to evaluate the level of patient knowledge about dental implants among a selected sample of dental patients in Tabriz, Iran. A total of 150 patients were selected from among those referring to Tabriz dental school. Patients’ knowledge regarding dental implants was evaluated through a questionnaire. The results of this study indicate that 60% of the subjects knew about dental implants. So that in 42% patients, dentists were the main source of information about dental implants. The survey concluded that an acceptable number of patients had heard of dental implants as a treatment option for replacing missing teeth, with dentists being the main source of information.

Statement of the Problem: Although the primary use of tissue conditioners is to treat abused mucosa, these materials are also frequently used as functional impression materials. Insufficient information is available on the effect of these materials on the surface of dental stone casts. This study evaluated the effect of a tissue conditioner (Acrosoft) on surface roughness of dental stone. A tissue conditioner, Acrosoft (Marlic Medical Industries Co., Iran) was evaluated. One impression material (Impregum) was used as control. Ten specimens of Impregum and 20 specimens of Acrosoft, stored in water bath for 24 hours (n=10) and 48 hours (n=10), were prepared. Ring and stone molds, specified in ISO specification 4823 and ADA specification 19, were used in this study. Then, the stone mold was adapted on the ring, and the dental stone (Velmix) was mixed, poured over the top of each specimen and allowed to remain for 60 minutes. Mean surface roughness (Ra) values of dental stone casts made from the tissue conditioner were determined using a profilometer. Ra values were compared with one-way and two-way ANOVA and Tukey test. The results indicated that the surface roughness values significantly increased with the Acrosoft compared to that with Imperium (P=0.000). Duration of immersion in water had no significant effect on the surface roughness of stone casts (P=0.54). Acrosoft cannot be used as a functional impression material because it is not compatible with dental stone

Statement of the problem: Many diseases to be treated by dentists require drug therapy. Lack of paying enough attention to principles of drug prescription can lead to problems such as unsuccessful treatment. On the other hand, the most important way to prevent such problems is paying enough attention to prescription of drugs. In this descriptive study, 260 prescriptions randomly gathered from 20 drugstores in Tabriz were evaluated. Each prescription was assessed on the basis of numbering, drug form, instructions, dosage, spelling and interactions. Data were analyzed using SPSS 15. 72.3% of prescriptions belonged to male and 27.7% belonged to female dentists. Of these 80.8% were prescribed by general dentists, 2.7% by post-graduate students and 16.5% by specialists. In order to assess the relation between the time of graduation and attention to principles, medical certificate number was used to categorize data. Principles of drug prescription were followed more accurately by female groups. Instructions and spelling received more attention by specialists and post-graduate students compared to general dentists, which might be attributed to the fact that more explanations are needed for specialized treatments offered to pharmacists and patients.

Internal bleaching technique is a common treatment option for discolored non-vital anterior teeth, but it is not advisable for cases with internal cervical resorption. Therefore, other conservative bleaching techniques, such as external bleaching, may be proper treatment options in this situation. Remaining discoloration should be covered by restorative options. The best choice for conservative restorations is ceramic laminate because of color stability, biocompatibility and durable esthetics. This clinical report presents the treatment of two severely discolored non-vital maxillary incisors with internal resorption in a 25-year-old man. A step-by-step practice is proposed for bleaching and restorative treatments of these discolored teeth are described.