Dental Research Journal
Volume:12 Issue: 1, Jan 2015

Congenitally missing teeth (CMT), or as usually called hypodontia, is a highly prevalent and costly dental anomaly. Besides an unfavorable appearance, patients with missing teeth may suffer from malocclusion, periodontal damage, insuffi cient alveolar bone growth, reduced chewing ability, inarticulate pronunciationand other problems. Treatment might be usually expensive and multidisciplinary. Thishighly frequent and yet expensive anomaly is of interest to numerous clinical, basic science and public health fi elds such as orthodontics, pediatric dentistry, prosthodontics, periodontics, maxillofacialsurgery, anatomy, anthropology and even the insurance industry. This essay reviews the fi ndings on the etiology, prevalence, risk factors, occurrence patterns, skeletal changes and treatments of congenitally missing teeth. It seems that CMT usually appears in females and in the permanent dentition. It is not conclusive whether it tends to occur more in the maxilla or mandible and also in the anterior versus posterior segments. It can accompany various complications and should be attended by expert teams as soon as possible.

Implant placement plays a vital role in oral rehabilitation following loss of the incisors. Thus, having knowledge of anatomical variations of adjacent neurovascular structures especially the nasopalatine canal (NPC) is essential. Due to the lack of basic information in Iran about the morphology of this canal and the probability of its variety in different populations, this study was designed on an Iranian population. In this descriptive study, we selected cone-beam computed tomography images of 198 patients comprising of 98 males and 100 females in two dental groups (edentulous or dentate). The shape of the nasopalatine foramen and the form of the canal in axial views were assessed. Then, the canal height and its diameter at the palatal, middle and nasal levels in crosssectional images were measured. The available bone in the buccal and palatal sides of the canal was assessed. Data analysis was carried out using a Chi-square test and an independent t-test (P ≤ 0.05). The majority of the samples (81.8%) presented a single foramen. Cylindrical shape (57.6%) was the most frequently detected canal form. The mean of the estimated canal height was 12.84 ± 2.88 mm. The canal diameter at the palatal level between the sexes and dental groups showed statistically signifi cant differences. In our investigated population, the NPC form was mainly cylindrical with a single opening foramen. The mean of the canal height was higher than that found in other populations. Furthermore, the canal diameter in the edentulous group was greater than that observed in the other group.

There have been numerous researches on ozone application in dentistry; yet the data regarding its whitening effect is very limited. The present study compares the bleaching effect of ozone with offi ce bleaching. In this experimental study, 15 maxillary premolar teeth were selected and sectioned mesio-distally and bucco-lingually. The sections were then placed in tea for 1 week according to the Sulieman method and were divided into three groups each comprised of 15 sections. The samples were bleached as followed; Group I: Bleached with 35% hydrogen peroxide in three intervals of 8 min each, Group II: Underwent ozone treatment using Ozotop unite for 4 min and Group III: Bleached with a combination of both methods. The color indices of the samples, i.e., (a) green-red pigment, (b) blue-yellow pigment, (L) brightness, (ΔE) overall color change, were evaluated pre- and post-bleaching utilizing a digital camera, Photoshop software and CIE lab index. The color changes of specimens then were calculated and analyzed through randomized analysis of variance and Tukey tests. P < 0.001 was considered to be signifi cant. The color change (ΔE) in Group II was signifi cantly lower than those in the two other groups (P < 0.001). There was no signifi cant difference between the color change of Groups I and III (P = 0.639). In addition, the results of L, a and b brought forth a similar pattern to the fi ndings obtained from ΔE. The hydrogen peroxide gel has a more powerful whitening effect than ozone; in addition, ozone has no synergistic effect when is used simultaneously with hydrogen peroxide.

Bone loss is one of the hallmarks of periodontitis. Hence, a major focus of research into periodontal regeneration has concentrated on the initiation of Osteogenesis. Osteoinduction requires the differentiation of mesenchymal cells into osteoblasts with subsequent formation of new bone. The present study has been carried out to evaluate periodontal bone regenerationin intrabony defects using osteostimulative oleaginous calcium hydroxide suspension Osteora® (Metacura, Germany) in combination with osteoconductive bone graft Ossifi ™ (Equinox Medical Technologies, Holland). A total of 22 sites in patients within the age range of 25-50 years, with intrabony defects were selected and divided into two groups (Group A and Group B) by using the split-mouth design technique. All the selected sites were assessed with the clinical parameters such as - Plaque Index, Gingival Index, Sulcus Bleeding Index, Periodontal Probing Depth,Clinical Attachment Level, Gingival Recession and radiographic parameter to assess the amount of Defect Fill. Mann-Whitey U-test and Wilcoxon Signed Rank Test has been used to fi nd the signifi cance of study parameters on continuous scale for the comparison between the mesial and distal bone levels. P < 0.05 was considered to be statistically signifi cant. Osteora® in combination with osteoconductive Ossifi ™ showed better regenerative potential and more signifi cant amount of bone fi ll in periodontal intrabony defects than when Ossifi ™ was used alone (P = 0.039). Osteora® can be used as an adjunct to osteoconductive bone grafts, as an osteostimulating agent in the treatment of periodontal intrabony defects.

Water fl uoride level is unknown in many regions of Iran. Besides, only few noncontrolled studies world-wide have assessed the effect of water fl uoride on dental fl uorosis and caries. We aimed to measure the fl uoride level of 76 water supplies in 54 cities and evaluate the effect of fl uoride on dental caries and fl uorosis in a large multi-project study. In the fi rst phase (cross-sectional), fl uoride levels of 76 water tanks in 54 cities/villages in fi ve provinces of Iran were randomly evaluated in fi ve subprojects. In the second phase (retrospective cohort), 1127 middle school children (563 cohort and 564 control subjects) in the high and low ends of fl uoride concentration in each subproject were visited. Their decayed, missing and fi lled teeth (DMFT) and fl uorosis states were assessed. The data were analyzed using Chi-square, Mann-Whitney U and independent-samples t-test (α = 0.05). Mean fl uoride level was 0.298 ± 0.340 mg/L in 54 cities/villages. Only eightwater tanks had fl uoride levels within the normal range and only one was higher than normal and the rest (67 tanks) were all at low levels. Overall, a signifi cant association was observed between fl uoride level and fl uorosis. However, this was not the case in all areas, as in 2 of 5 provinces, the effect of fl uoride on fl uorosis was not confi rmed. In 4 of the 5 areas studied, there was a signifi cant link between fl uoride level and DMFT. Extremely low fl uoride levels in Iran cities are an alarming fi nding and need attention. Higher fl uoride is likely to reduce dental caries while increasing fl uorosis. This fi nding was not confi rmed in all the areas studied.

The purpose of this study was to compare the effi cacy of EndoVac irrigation system and side-vented closed ended needle (Max-I probe) in removing smear layer from root canals at 1 mm and 3 mm from working length using ProTaper rotary instrumentation. A total of 50 freshly extracted maxillary central incisors were randomly divided into two groups after complete cleaning and shaping with ProTaper rotary fi les. In one group, fi nal irrigation was performed with EndoVac system while in other group, fi nal irrigation was done with a 30 gauge Max-I probe. 3% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetracetic acid were used as fi nal irrigants in all teeth. During instrumentation, 1 ml of 3% NaOCl was used for irrigation after each rotary instrument in the similar manner as in fi nal irrigation. After instrumentation and irrigation, teeth were sectioned longitudinally into buccal and palatal halves and viewed under scanning electron microscope for evaluation of smear layer. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U-test. (P < 0.05) At 3 mm level, there was no signifi cant difference between two groups. At 1 mm level, EndoVac group showed signifi cantly better smear layer removal compared with Max-I probe (P = 0.0001). EndoVac system results in better smear layer removal at 1 mm from working length when compared to Max-I probe irrigation.

Metal nanoparticles have been recently applied in dentistry because of their antibacterial properties. This study aimed to evaluate antibacterial effects of colloidal solutions containing zinc oxide (ZnO), copper oxide (CuO), titanium dioxide (TiO2) and silver (Ag) nanoparticles on Streptococcus mutans and Streptococcus sangius and compare the results with those of chlorhexidine and sodium fl uoride mouthrinses. After adding nanoparticles to a water-based solution, six groups were prepared. Groups I to IV included colloidal solutions containing nanoZnO, nanoCuO, nanoTiO2 and nanoAg, respectively. Groups V and VI consisted of 2.0% sodium fl uoride and 0.2% chlorhexidine mouthwashes, respectively as controls. We used serial dilution method to fi nd minimum inhibitory concentrations (MICs) and with subcultures obtained minimum bactericidal concentrations (MBCs) of the solutions against S. mutans and S. sangius. The data were analyzed by analysis of variance and Duncan test and P < 0.05 was considered as signifi cant. The sodium fl uoride mouthrinse did not show any antibacterial effect. The nanoTiO2- containing solution had the lowest MIC against both microorganisms and also displayed the lowest MBC against S. mutans (P < 0.05). The colloidal solutions containing nanoTiO2 and nanoZnO showed the lowest MBC against S. sangius (P < 0.05). On the other hand, chlorhexidine showed the highest MIC and MBC against both streptococci (P < 0.05). The nanoTiO2-containing mouthwash proved to be an effective antimicrobialagent and thus it can be considered as an alternative to chlorhexidine or sodium fluoride mouthrinses in the oral cavity provided the lack of cytotoxic and genotoxic effects on biologic tissues.

Different environmental conditions, such as high temperature or exposure to some chemical agents, may affect the force decay of different methods of space closure during orthodontic treatment. The aim of this in vitro study was to evaluate the force decay pattern in thepresence of tea as a popular drink in some parts of the world and two mouthwashes that are usually prescribed by the orthodontist once the treatment is in progress. Elastic chain (EC), nickel-titanium (Ni-Ti) closed coil spring and tie back (TB) method were used as the means of space closure. The specimens were placed in fi ve different media: Hot tea, hot water (65°), chlorhexidine mouthwash, fl uoride mouthwash and the control group (water at 37°). The specimens were stretched 25 mm and the elastic force of three systems was measured at the beginning of the study, after 24 h, after 1 week and after 3 weeks. One-way ANOVA was used to compare the results between the groups and Duncan test was carried out to compare the sets of means in different groups (P ≤ 0.05). Tea increases the force decay in the EC and TB groups. Oral mouthwashes also resulted in more rapid force decay than the control group. EC and Ni-Ti groups were not much affected in the presence of oral mouthwashes. Regarding the immersion media, TB method showed the biggest variation in different media and Ni-Ti coil spring was least affected by the type of media.

Osseointegration of dental implants is infl uenced by many biomechanical factors that may be related to stress distribution. The aim of this study was to evaluate the effect of type of luting agent on stress distribution in the bone surrounding implants, which support a three-unit fi xed dental prosthesis (FDP) using fi nite element (FE) analysis. A 3D FE model of a three-unit FDP was designed replacing the maxillary fi rst molar with maxillary second premolar and second molar as the abutments using CATIA V5R18 software and analyzed with ABAQUS/CAE 6.6 version. The model was consisted of 465108 nodes and 86296 elements and the luting agent thickness was considered 25 μm. Three load conditions were applied on eight points in each functional cusp in horizontal (57.0 N), vertical (200. N) and oblique (400.0 N, θ = 120°) directions. Five different luting agents were evaluated. All materials were assumed to be linear elastic, homogeneous, time independent and isotropic. For all luting agent types, the stress distribution pattern in the cortical bone, connectors, implant and abutment regions was almost uniform among the three loads. Furthermore, the maximum von Mises stress of the cortical bone was at the palatal side of second premolar. Likewise, the maximum von Mises stress in the connector region was in the top and bottom of this part. Luting agents transfer the load to cortical bone and different types of luting agents do not affect the pattern of load transfer.

The aim of the present study was to estimate chronological age based on third molar development and to determine the association between dental age and third molar calcifi cation stages. In this cross-sectional study, 505 digital panoramic radiographs of 223 males (44.2%) and 282 females (55.8%) between the age of 6 and 17 were selected from patients who were treated in Departments of Pediatrics and Orthodontics of Isfahan University of Medical Sciences between the years of 2009 and 2013. Correlation between chronological age and third molar development was analyzed with SPSS 21 using Spearman’s Rank correlation coeffi cient, Chi-square test and multiple regression statistical tests (P < 0.05). All third molars demonstrated a highly signifi cant correlation with dental age (P < 0.001). The teeth showing the highest relationship with dental age were mandibular left third molar in males and mandibular right third molar in females (rs = 0.072). When multiple regression was used to predict dental age based on molar calcifi cation stage, the only signifi cant correlation was between maxillary left third molar in males (P < 0.05). There was no statistically signifi cant correlation for any of third molars in females. Relationship between chronological age and molars development stage was signifi cant in all age subgroups and in both gender (P < 0.001). Strong correlation was observed between left third molars and dental age in males. Results showed that third molar calcifi cation stage can be used as an age predictor and in general mandibular teeth seems to be more reliable for this purpose in both genders and in all ages.

The aim of this study was to determine the pattern and amount of change exhibited in mandibular intercanine and intermolar width during treatment and assessing its stabilit 1-3 years post-retention. The material consisted of 70 cases of which 20 cases were treated without extraction and 30 cases were treated with extraction, which were compared with 20 untreated cases which served as a control group. A series of three measurements were made for each case of the treated group: At the beginning of treatment, end of active treatment and 1-3 years post-retention; and for the control group: At 12, 15 and 18 years of age. The Wilcoxon signed ranks test was used to evaluate treatment changes in each group. The Kruskal-Wallis H test was used to compare the treatment changes between the 3 groups (α = 0.05). SPSS 16 software (SPSS Inc., Chicago, IL, USA) was used to evaluate the data. Mean changes of intercanine width for three groups was −0.5 mm for control group, −0.26 mm for non-extraction group and +0.18 mm for extraction group. Intermolar width of the extraction group decreased signifi cantly during treatment. In contrast to the extraction group, the control and non-extraction groups both demonstrated an increase in mean intermolar width which was 0.66 mm and 0.91 mm respectively. It was concluded that although mean changes of intercanine and intermolar width were statistically signifi cant but they were not perceptible clinically.

There is a strong evidence that genetic as well as environmental factors affect the age of onset, severity and lifetime risk of developing periodontitis. The objective of the present study was to compare and to evaluate the association between interleukin (IL)-1α(-889) and gene polymorphisms in patients with generalized aggressive periodontitis, chronic periodontitis and healthy controls. A total of 60 Indian patients, with 20 aggressive periodontitis, 20 chronic periodontitis and 20 healthy controls were recruited for this study. From each patient, a volume of 2 ml of blood was collected by venipuncture in the ante-cubital fossa and was stored in sodium EDTA vacutainers and was used for genotyping assays with the polymerase chain reaction restriction fragment length polymorphism technique. Clinical parameters such as oral hygiene index, gingival index and clinical attachment loss (CAL) were evaluated for each patient. Genotype distribution between different groups were analyzed using Chi-square test. A P = 0.05 or less was set for signifi cance. The mean oral hygiene index was 3.7 ± 0.86 and 3.25 ± 0.30 for chronic and aggressive periodontitis cases respectively. The CAL was 4.29 ± 0.63 mm for chronic periodontitis and 6.44 ± 0.57 mm for aggressive periodontitis. Homozygous genotype 2,2 was more predominant in cases of aggressive periodontitis whereas in chronic periodontitis, heterozygous genotype 1,2 was more predominant when compared with others (P < 0.001). Odds ratio for aggressive versus chronic periodontitis was calculated as 6.2 (95% confi dence interval 6.019-7.892). The results of the present study support a positive association between aggressive periodontitis and the presence of the IL-1α-889, allele 2 polymorphism in Indian patients.

Many oral squamous cell carcinomas (OSCCs) arise within regions that previously had premalignant lesion. Early diagnosis and prompt treatment of premalignant lesions offers the best hope of improving the prognosis in patients with OSCC. Exfoliative cytology is a simple and non-invasive diagnostic technique that could be used for early detection of oral premalignant and malignant lesions. This study was undertaken to evaluate the quantitative changes in nuclear area (NA), cytoplasmic area (CA) and nuclear-to-cytoplasmic ratio (NA/CA) in cytological buccal smears of oral leukoplakia with dysplasia (OLD) and OSCC patients while comparing with normal healthy mucosa. A quantitative study was conducted over 90 subjects including 30 cases each of OLD, OSCC and clinically normal oral mucosa. The smears obtained were stained with Papanicolaou (PAP) stain and cytomorphological assessment of the keratinocytes was carried out. The statistical tools included arithmetic mean, standard deviation, Chi-square test, analysis of variance, Tukey multiple comparison. P < 0.001 was considered as signifi cant. The mean NA of keratinocytes in the normal mucosa was 65.47 ± 4.77 μm2 while for OLD it was 107.97 ± 5.44 μm2 and 139.02 ± 8.10 μm2 for that of OSCC. The differences show a statistically signifi cant increment in NA (P < 0.001). There was signifi cant reduction (P < 0.001) in the CA of keratinocytes from OSCC when compared with those from smears of OLD and normal mucosa with the values of 1535.80 ± 79.38 μm2, 1078.51 ± 56.65 μm2 and 769.70 ± 38.77 μm2 respectively. The NA/CA ratio in the smears from normal oral mucosa, OLD and OSCC showed a mean value of 0.043 ± 0.004, 0.100 ± 0.008, 0.181 ± 0.015 respectively with a signifi cant difference among the groups (P < 0.001). Evaluation of nuclear and CA of keratinocytes by cytomorphometry can serve as a useful adjunct in the diagnosis and prognosis of a dysplastic lesion which may lead to OSCC.

The aim of this study was to evaluate the interaction of bioactive and biodegradable poly (lactide-co-glycolide)/bioactive glass/hydroxyapatite (PBGHA) and poly (lactide-co-glycolide)/bioactive glass (PBG) nanocomposite coatings with bone. Sol-gel derived 58S bioactive glass nanoparticles, 50/50 wt% poly (lactic acid)/poly (glycolic acid) and hydroxyapatite nanoparticles were used to prepare the coatings. The nanocomposite coatings were characterized by scanning electron microscopy, X-ray diffraction and atomic force microscopy. Mechanical stability of the prepared nanocomposite coatings was studied during intramedullary implantation of coated Kirschner wires (K-wires) into rabbit tibia. Titanium mini-screws coated with nanocomposite coatings and without coating were implanted intramedullary in rabbit tibia. Bone tissue interaction with the prepared nanocomposite coatings was evaluated 30 and 60 days after surgery. The non-parametric paired Friedman and Kruskal-Wallis tests were used to compare the samples. For all tests, the level of signifi cance was P < 0.05. The results showed that nanocomposite coatings remained stable on the K-wires with a minimum of 96% of the original coating mass. Tissue around the coated implants showed no adverse reactions to the coatings. Woven and trabecular bone formation were observed around the coated samples with a minimum infl ammatory reaction. PBG nanocomposite coating induced more rapid bone healing than PBGHA nanocomposite coating and titanium without coating (P < 0.05). It was concluded that PBG nanocomposite coating provides an ideal surface for bone formation and it could be used as a candidate for coating dental and orthopedic implants.

Myiasis is the condition of infestation of the body by fl y larvae (maggots). The deposited eggs develop into larvae, which penetrate deep structures causing adjacent tissue destruction. It is an uncommon clinical condition, being more frequent in tropical countries and hot climate regions, and associated with poor hygiene, suppurative oral lesions, alcoholism and senility. The diagnosis of Myiasis is basically made by the presence of larvae. The reported cases of oral Myiasisassociated with oral cancer in the literature are few. This paper reports two cases of oral and maxillofacial Myiasis involving larvae in patients with squamous cell carcinoma in adult males. The condition was managed by manual removal of the larvae, one by one, with the help of forceps and subsequent management through proper health care.