Retention strength of cobalt-chromium vs nickel-chromium titanium vs Cp titanium in a cast framework association of removable partial overdenture

Aim: There is little information considering the framework association between cast clasps and attachments. The aim of this study was to evaluate the retention strength of frameworks match circumferential clasps and extra resilient attachment cast in three different alloys (cobalt-chromium, nickel-chromium titanium and commercially pure titanium), using two undercut (0.25 and 0.75 mm) and considering different period of time (0, 1/2, 1, 2, 3, 4 and 5 years). Methods: Using two metallic matrices, representing a partially edentulous mandibular right hemiarch with the first molar crown, canine root and without premolars, 60 frameworks were fabricated. Three groups (n = 20) of each metal were cast and each group was divided into two subgroups (n = 10), corresponding the molar undercut of 0.25 mm and 0.75 mm. The nylon male was positioned at the matrix and attached to the acrylic resin of the prosthetic base. The samples were subjected to an insertion and removal test under artificial saliva environment. Results: The data were analyzed and compared with ANOVAs and Tukey's test at 95% of probability. The groups cast in cobaltchromium and nickel-chromium-titanium had the highest mean retention strength (5.58 N and 6.36 N respectively) without significant difference between them, but statistically different from the group cast in commercially pure titanium, which had the lowest mean retention strength in all the periods (3.46 N). The association frameworks using nickel-chromium-titanium and cobalt-chromium could be used with 0.25 mm and 0.75 mm of undercut, but the titanium samples seems to decrease the retention strength, mainly in the 0.75 mm undercut. The circumferential clasps cast in commercially pure titanium used in 0.75 mm undercuts have a potential risk of fractures, especially after the 2nd year of use. Conclusion: This in vitro study showed that the framework association between cast clasp and an extra resilient attachment are suitable to the three metals evaluated, but strongly suggest extra care with commercially pure titanium in undercut of 0.75 mm. Clinical significance: Frameworks fabricated in Cp Ti tend to decrease in retentive strength over time and have a potential risk of fracture in less than 0.75 mm of undercut.

Bonding all-ceramic restorations with two resins cement techniques: A clinical report of three-year follow-up

Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate. This article presents three-year clinical results of a 41 years old female patient B.H.C complaining about her unattractive smile. Two all-ceramic crowns and two laminates veneers were placed in the maxillary incisors and cemented with a self-adhesive resin luting cement and conventional resin luting cement, respectively. After a three-year follow-up, the restorations and cement/teeth interface were clinically perfect with no chipping, fractures or discoloration. Proper use of different resin luting cements shows clinical appropriate behavior after a three-year follow-up. Self-adhesive resin luting cement may be used for cementing all-ceramic crowns with high predictability of success, mainly if there is a large dentin surface available for bonding and no enamel at the finish line. Otherwise, conventional resin luting agent should be used for achieving an adequate bonding strength to enamel.

Nd:YAG Laser Irradiation effect on apical intracanal dentin-a microleakage and SEM evaluation

The purpose of this in vitro study was to evaluate the effect of neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation on intracanal dentin surface by SEM analysis and its interference in the apical seal of filled canals. After endodontic treatment procedures, 34 maxillary human incisors were randomly assigned to 2 groups. In the negative control group (n=17), no additional treatment was performed and teeth were filled with vertically condensed gutta-percha; in the laser-treated group (n=17), the root canals were irradiated with Nd:YAG laser (1.5 W, 100 mJ, 15 Hz) before filling as described for the control group. Two specimens of each group were prepared for SEM analysis to evaluate the presence and extent of morphological changes and removal of debris; the other specimens were immersed in 0.5% methylene blue dye (pH 7.2) for 24 h for evaluation of the linear dye leakage at the apical third. SEM analysis of the laser-treated group showed dentin fusion and resolidification without smear layer or debris. The Student's t-test showed that the laser-treated group had significantly less leakage in apical third than the control group. Within the limitations of this study, it may be concluded that the morphological changes on the apical intraradicular dentin surface caused by Nd:YAG laser resulted in less linear dye apical leakage.

Evaluation of transverse changes in the dental arches according to growth pattern: a longitudinal study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dental age as indicator of adolescence

Aim: The purpose of the present study was to analyze the relationship between root formation of the first premolars and skeletal maturation stages identified in hand-wrist radiographs. Methods: A cross-sectional study was carried out involving the panoramic and hand-wrist radiographs obtained on the same date of 232 patients, 123 boys and 109 girls aged 4 years and 5 months to 17 years and 12 months. Root formation stages of the first premolars were related to the ossification stages of the sesamoid bone, epiphyseal stages of the phalanx of the thumb and epiphyseal stages of the radius. Results: The studied variables demonstrated statistically significant correlations. Conclusion: Roots of the lower first premolars do not reach 2/3 of their complete length before adolescence.

Conservative reconstruction of the smile by orthodontic, bleaching, and restorative procedures

The following is a clinical case report of a patient whose chief complaint was the presence of generalized spacing in the maxillary anterior segment following orthodontic treatment. After meticulous clinical analyses and discussions of the clinical procedures to be adopted, dental bleaching was performed in both arches with 10% hydrogen peroxide (Opalescence Trèswhite Supreme 10% Hydrogen Peroxide - Ultradent Products, Inc., South Jordan, USA) after the conclusion and stabilization of orthodontic treatment. Then, the orthodontic appliance was removed and the diastemas in the maxillary anterior teeth were closed with Amelogen Plus (Ultradent Products, Inc., South Jordan, USA) resin composite. It was observed that the association of orthodontic, bleaching, and restorative procedures was capable of restoring dental shape, function, and esthetics, allowing the patient to smile without hesitation.

Cephalometric evaluation of hyoid bone position in a patient with Down syndrome: Case report

The hyoid bone contributes to the maintenance of the airway, chewing and swallowing, given to its anatomical and functional relations to the craniocervical complex. Cephalometric analysis has great importance for orthopedics, orthodontics and oral maxillary surgery. For the treatment of patients with special care needs, the cephalometric evaluation of the position of the hyoid bone should also contribute as a complementary element for dental diagnosis and the selection of the adequate treatment. The aim of this paper is to demonstrate the alteration of the hyoid position after carrying out the functional orthopedic maxillary treatment in a 9 year-old patient with Down Syndrome. Initial cephalometric analysis revealed inadequate position of hyoid bone. The association of speech therapy to dynamic functional rehabilitation of jaws showed a positive effect in occlusal relation and facial expression. After treatment, all dimensions obtained from the hyoid triangle were higher than initial ones, except the anterior-posterior value of C3-H, which suggested function improvement of stomatognathic system. Once considered its anatomical and physiological relationship with the others structures of the stomatognathic system, cephalometric analysis of hyoid bone position was helpful to the comprehension of the craniofacial abnormalities related to chromosomal anomaly, and thus is essential to the interdisciplinary dialogue.

Occurrence of traumatic dental injury in cases of domestic violence

The purpose of this study was to investigate the prevalence and types of traumatic dental injuries in situations of domestic violence. A coross-sectional study was conducted and data were collected from the police occurrence records to domestic physical aggression between 2001 and 2005. Of the 1,844 subjects who underwent medical evaluation, 15 had information pertaining to traumatic dental injuries. From the medical records, the forensic medical reports completed by the forensic medical experts who examined the victims after the aggression were reviewed and data of individuals with dental injuries (e.g., fractures, luxation and avulsion) were collected. In the selected sample, there was a predominance of individuals with injuries to the head and neck region (38.7%), and the frequency of traumatic dental injuries among all injuries to the head and neck region was 2.0%. The most frequently injured teeth were the maxillary incisors (31.8%), followed by the mandibular incisors (27.3%) and the maxillary canines (9.1%). In 31.8% of the injured teeth, the forensic experts did not specify the nomenclature. Of the dental trauma cases, 59.1% were fractures, 27.2% were luxations and 13.7% were avulsions. In conclusion, domestic violence was an important etiologic factor of traumatic dental injury. The aggression in all cases occurred in the form of punches and slaps. Fracture was the most common type of traumatic dental injury, and the most frequently injured teeth were the incisors.

Complete denture wearing and fractures among edentulous patients treated in university clinics

Objective: The prevalence of wearing and fracture of complete dentures was evaluated among edentulous patients treated in two dental schools in Brazil. Background: Acceptance and wearing of complete dentures are related to adaptive behaviour of edentulous patients. However, one reason that could interfere with the wearing dentures is their potential to fracture, which is still a common complication in denture rehabilitation practice. Material and methods: Two hundred and twenty-four edentulous patients rehabilitated with complete dentures from 2000 to 2005 in Araçatuba and Araraquara Dental School, University of State of São Paulo, were assessed in 2006 and 2007 to answer a questionnaire about wearing and fracture of their dentures. Statistical analysis were performed using Epi Info software and chi-squared test to compare maxillary and mandibular data (α = 0.05). Results: Almost 26% of the patients did not wear their dentures, and among the remainder, the majority wore the maxillary denture. About 30% of the dentures were fractured, with higher prevalence in the maxillary arch (p = 0.003). Conclusions: Discontinuation of wearing dentures was quite high, especially considering the treatment which was carried out in university clinics. Prevalence of fractures was also high, greater for the maxillary denture, and was one of the main reasons for non-wearing of complete dentures. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

The challenges of treating a fused tooth

This paper describes and discusses the multidisciplinary treatment involving a permanent maxillary lateral incisor fused to a supernumerary tooth, both presenting pulp necrosis and periapical lesion. A 15-year-old male patient sought treatment complaining of pain, swelling and mobility on the maxillary right lateral incisor. After clinical and radiographic examination, root canal preparation was performed according to the crown-down technique and a calcium hydroxide dressing was placed for 15 days. The patient returned and the definitive endodontic filling was done with thermomechanical compaction of gutta-percha and sealer. After 18 months, clinical and radiographic examinations were carried out and no pain or swelling was reported. Two years after endodontic treatment, the patient returned for periodontal and cosmetic treatments. Nine months later, a cone-beam computed tomography (CBCT) revealed that the previously detected periodontal defect and periapical lesion were persistent. Apical endodontic surgery was indicated. The supernumerary tooth was removed, the communicating distal surface was filled and the surgical site received bioactive glass and demineralized bovine organic bone. The pathological tissue was submitted to histopathological examination and the diagnosis was periapical cyst. One year after the apical endodontic surgery, CBCT showed bone formation at maxillary lateral incisor apical area. Two years after the surgery, the restoration was replaced due to aesthetic reasons and periapical radiograph showed success after 5 years of treatment. A correct diagnosis and establishment of an adequate treatment plan resulted in a successful management of the case.

Expression of opg, rank, and rankl proteins in tooth repair processes after immediate and delayed tooth

This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the repair after immediate and delayed replantation of rat teeth. Fifty-six Wistar rats (Rattus norvegicus albinus) had their maxillary right lateral incisor extracted and then replanted, according to the following conditions: group I (control; n = 8), teeth were not extracted; group II (n = 16), immediate replantation; group III (n = 16), delayed replantation without treatment; and group IV (n = 16), delayed replantation after root surface treatment (periodontal ligament removal and immersion in 2% acidulated-phosphate sodium fluoride) and calcium hydroxide intracanal dressing. Rats in group I were euthanized on the first day of the experiment, while the animals in the other groups were euthanized 10 and 60 days after replantation (n = 8/period). Hematoxylin and eosin-stained sections were obtained for histological analysis. The immunohistochemical analysis revealed expression of OPG and RANKL proteins in all groups and both postreplantation times, except for group II at 60 days. In the experimental groups, RANK expression was observed only at 10 days. In conclusion, there was strong immunostaining for the OPG-RANK-RANKL system at the earlier postreplantation time, suggesting a more effective participation of these proteins at the start of the healing process, as their expression decreased at 60 days. Copyright © 2013 by Mutaz B. Habal, MD.

Alveolar bony crest preservation at implants installed immediately after tooth extraction: An experimental study in the dog

Aim: To evaluate the influence of deproteinized bovine bone mineral in conjunction with a collagen membrane, at implants installed into sockets in a lingual position immediately after tooth extraction, and presenting initial horizontal residual buccal defects <2 mm. Material and methods: The pulp tissue of the mesial roots of 4P4 was removed in six Labrador dogs, and the root canals were filled with gutta-percha and cement. Flaps were elevated, and the buccal and lingual alveolar bony plates were exposed. The premolars were hemi-sectioned, and the distal roots were removed. Implants were installed in a lingual position and with the margin flush with the buccal bony crest. After installation, defects resulted at about 1.7 mm in width at the buccal aspects, both at the test and control sites. Only in the left site (test), deproteinized bovine bone mineral (DBBM) particles were placed into the defect concomitantly with the placement of a collagen membrane. A non-submerged healing was allowed. Results: After 3 months of healing, one implant was found not integrated and was excluded from the analysis together with the contralateral control implant. All remaining implants were integrated into mature bone. The bony crest was located at the same level of the implant shoulder, both at the test and control sites. At the buccal aspect, the most coronal bone-to-implant contact was located at a similar distance from the implant margin at the test (1.7 ± 1.0 mm) and control (1.6 ± 0.8 mm) sites, respectively. Only small residual DBBM particles were found at the test sites. Conclusion: The placement of an implant in a lingual position into a socket immediately after tooth extraction may favor a low exposure of the buccal implant surface. The use of DBBM particles, concomitantly with a collagen membrane, did not additionally improve the outcome obtained at the control sites. © 2011 John Wiley & Sons A/S.

Detection of cavitated approximal surfaces using cone beam CT and intraoral receptors

Objectives: The aim of this study was to compare cone beam CT (CBCT) in a small field of view (FOV) with a solid-state sensor and a photostimulable phosphor plate system for detection of cavitated approximal surfaces. Methods: 257 non-filled approximal surfaces from human permanent premolars and molars were recorded by two intraoral digital receptors, a storage phosphor plate (Digora Optime, Soredex) and a solid-state CMOS sensor (Digora Toto, Soredex), and scanned in a cone beam CT unit (3D Accuitomo FPD80, Morita) with a FOV of 4 cm and a voxel size of 0.08 mm. Image sections were carried out in the axial and mesiodistal tooth planes. Six observers recorded surface cavitation in all images. Validation of the true absence or presence of surface cavitation was performed by inspecting the surfaces under strong light with the naked eye. Differences in sensitivity, specificity and agreement were estimated by analysing the binary data in a generalized linear model using an identity link function. Results: A significantly higher sensitivity was obtained by all observers with CBCT (p,0.001), which was not compromised by a lower specificity. Therefore, a significantly higher overall agreement was obtained with CBCT (p,0.001). There were no significant differences between the Digora Optime phosphor plate system and the Digora Toto CMOS sensor for any parameter. Conclusions: CBCT was much more accurate in the detection of surface cavitation in approximal surfaces than intraoral receptors. The differences are interpreted as clinically significant. A CBCT examination performed for other reasons should also be assessed for approximal surface cavities in teeth without restorations. © 2013 The British Institute of Radiology.

Apexification with white MTA in an immature permanent tooth with dens invaginatus

Dens invaginatus, also known as dens in dente, is a developmental dental anomaly resulting in an invagination of the enamel organ into the dental papilla. These cases present technical difficulties to the root canal treatment. Apexification using an apical plug of mineral trioxide aggregate (MTA) has been indicated as an alternative to long-term intracanal use of calcium hydroxide in immature permanent teeth. It is considered as a simple and rapid technique. This paper reports a case of Oehlers' Type 1 dens invaginatus in an immature permanent maxillary right lateral incisor, which presented pulp necrosis secondary to dental trauma and was treated by apexification with white MTA apical plugging followed by conventional root canal therapy. The operative procedures are described and the technique is discussed. The physical and biological properties of MTA, associated with appropriate instrumentation and obturation techniques, make this material an excellent option in the endodontic therapy of immature permanent teeth with dens invaginatus.