Absence and hypoplasia of the mental foramen detected in CBCT images: a case report

The mental foramen (MF) is an important anatomic landmark of the mandible, through which the mental nerve and blood vessels emerge. The importance of MF in dental practice is especially related to dental implants placement and other surgical procedures in the region. It is fundamental to be careful in order to avoid nerve and vessels injury during procedures. Anatomic variations of the MF can be found, such as occurrence of multiple foramina and unusual location. In very rare occasions, the absence of MF can be detected. The observation of this variation is not always possible using only conventional radiographs. The modern imaging resource cone beam computed tomography (CBCT) allows an accurate three-dimensional assessment of MF, as well as the identification of its variations. The aim of this article is to report MF absence and hypoplasia detected in CBCT images of a 27-year-old daughter and her 63-year-old mother, both from Brazil. Despite the MF anatomic variations, they presented no sensorial disturbance in the regions supplied by the mental nerve.

Biomechanical and Microscopic Response of Bone to Titanium Implants in the Presence of Inorganic Grafts

This study evaluated the biomechanical and microscopic response of previously grafted bone to titanium implants. The lower incisors of 16 rabbits were surgically extracted, and bilateral perforations communicating with the remaining sockets were created distally. A socket/perforation defect on each mandible was chosen at random to be immediately filled with a xenogenic graft, whereas the contralateral perforation was left to heal naturally and served as a paired control. After 60 days, titanium implants were installed in the previously operated areas. After periods of 2 and 6 months, the animals were killed, and the force necessary to retrieve implants as well as the bone-implant contact (BIC) and bone mass (BM) were quantified and statistically compared by 2-way analysis of variance and Tukey`s test (alpha = .05). No significant differences in removal torque were observed, either by time or by treatment condition. Differences in BIC and BM between experimental and control groups were not statistically significant through the intervals studied (P < .05). The presence of a xenogenic graft did not influence the microscopic tissue response to titanium implants or fixation into newly formed or mature bone.

A longitudinal study of quality of life of elderly with mandibular implant-supported fixed prostheses

Objectives: To verify the consequences of implant-supported fixed oral rehabilitation on the quality of life (QL) of elderly individuals. Material and methods: Fifteen patients were studied, being 10 females and five males; all were aged > 60 years, were completely edentulous, wore removable dentures on both arches, and were treated with implant-supported fixed dentures. Three QL questionnaires were applied, two related to the oral conditions (Oral Impact on Daily Performance - OIDP - and Oral Health Impact Profile, short version - OHIP-14) and one dealing with global aspects (World Health Organization Quality of Life - WHOQOL-BREF), before 3, 6, and 18 months after surgical placement of implants. Results: Scores in the OIDP and OHIP-14 questionnaires were better after dental treatment. The WHOQOL-BREF was less sensitive, confirming the higher reliability of specific questionnaires (focal) compared with general questions in such situations. Conclusion: Treatment with implant-supported fixed prostheses improved QL in the elderly; these effects are better detected by specific instruments focused on the subject.

Relational learning in children with deafness and cochlear implants

This four-experiment series sought to evaluate the potential of children with neurosensory deafness and cochlear implants to exhibit auditory-visual and visual-visual stimulus equivalence relations within a matching-to-sample format. Twelve children who became deaf prior to acquiring language (prelingual) and four who became deaf afterwards (postlingual) were studied. All children learned auditory-visual conditional discriminations and nearly all showed emergent equivalence relations. Naming tests, conducted with a subset of the: children, showed no consistent relationship to the equivalence-test outcomes.. This study makes several contributions: to the literature on stimulus equivalence. First; it demonstrates that both pre- and postlingually deaf children-can: acquire auditory-visual equivalence-relations after cochlear implantation, thus demonstrating symbolic functioning. Second, it directs attention to a population that may be especially interesting for researchers seeking to analyze the relationship. between speaker and listener repertoires. Third, it demonstrates the feasibility of conducting experimental studies of stimulus control processes within the limitations of a hospital, which these children must visit routinely for the maintenance of their cochlear implants.

Auditory Neuropathy/Auditory Dyssynchrony in children with Cochlear Implants

The electrical stimulation generated by the Cochlear Implant (CI) may improve the neural synchrony and hence contribute to the development of auditory skills in patients with Auditory Neuropathy / Auditory Dyssynchrony (AN/AD). Aim: Prospective cohort cross-sectional study to evaluate the auditory performance and the characteristics of the electrically evoked compound action potential (ECAP) in 18 children with AN/AD and cochlear implants. Material and methods: The auditory perception was evaluated by sound field thresholds and speech perception tests. To evaluate ECAP`s characteristics, the threshold and amplitude of neural response were evaluated at 80Hz and 35Hz. Results: No significant statistical difference was found concerning the development of auditory skills. The ECAP`s characteristics differences at 80 and 35Hz stimulation rate were also not statistically significant. Conclusion: The CI was seen as an efficient resource to develop auditory skills in 94% of the AN/AD patients studied. The auditory perception benefits and the possibility to measure ECAP showed that the electrical stimulation could compensate for the neural dyssynchrony caused by the AN/AD. However, a unique clinical procedure cannot be proposed at this point. Therefore, a careful and complete evaluation of each AN/AD patient before recommending a Cochlear Implant is advised. Clinical Trials: NCT01023932

Effects of Mandibular Fixed Implant-Supported Prostheses on Masticatory and Swallowing Functions in Completely Edentulous Elderly Individuals

To evaluate the effect of oral rehabilitation with immediately loaded fixed implant-supported mandibular prostheses on chewing and swallowing in elderly individuals. Materials and Methods: Fifteen completely edentulous patients aged more than 60 years (10 women and five men), wearing removable dentures in both arches, had a mandibular denture replaced by an implant-supported prosthesis. All individuals were evaluated before surgery and again 3, 6, and 18 months later with regard to mastication and swallowing conditions. Examinations entailed an interview, evaluation of tactile sensitivity of the face, and observation of food intake, masticatory type, formations of bolus, and pain during mastication. The swallowing evaluation comprised observation of clinical signs related to the oral and pharyngeal stages of swallowing, as well as the presence of oral residue. The findings of different evaluations before and 3, 6, and 18 months after the surgical-prosthetic procedure were statistically compared by analysis of variance for repeated measurements at a significance level of 5%. Results: The questionnaire revealed a reduction in complaints of masticatory and swallowing disturbances, a decreased need for liquid ingestion, and reduced choking and coughing. Clinical evaluations showed improved oral function and bolus propulsion for both solid and paste-consistency foods; pain during mastication was also resolved. Conclusion: Treatment with mandibular implant-supported dentures had positive effects on the clinical aspects of mastication and swallowing in elderly individuals. INT J ORAL MAXILLOFAC IMPLANTS 2009; 24:110-117

Orthodontic-surgical treatment of Class III malocclusion with extraction of an impacted canine and multi-segmented maxillary surgery

Establishment of a treatment plan is based on efficacy and easy application by the clinician, and acceptance by the patient. Treatment of adult patients with Class III malocclusion might require orthognathic surgery, especially when the deformity is severe, with a significant impact on facial esthetics. Impacted teeth can remarkably influence treatment planning, which should be precise and concise to allow a reasonably short treatment time with low biologic cost. We report here the case of a 20-year-old man who had a skeletal Class III malocclusion and impaction of the maxillary right canine, leading to remarkable deviation of the maxillary midline; this was his chief complaint. Because of the severely deviated position of the impacted canine, treatment included extraction of the maxillary right canine and left first premolar for midline correction followed by leveling, alignment, correction of compensatory tooth positioning, and orthognathic surgery to correct the skeletal Class III malocclusion because of the severe maxillary deficiency. This treatment approach allowed correction of the maxillary dental midline discrepancy to the midsagittal plane and establishment of good occlusion and optimal esthetics. (Am J Orthod Dentofacial Orthop 2010;137:840-9)

Open-bite orthodontic-surgical treatment in the Klippel-Trenaunay-Weber syndrome: a case report

We describe the orthodontic treatment of a patient with Klippel-Trenaunay-Weber syndrome (KTWS) who received orthodontic treatment that included rapid palatal expansion and orthognathic surgery. There is no report in the literature with this orthodontic treatment protocol, that was considered successful. The pros and cons of this approach as well as the risks involved are discussed. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: e17-e25)

Experimental Surgical and Orthodontic Extrusion of Teeth in Dogs

The purpose of this study was to evaluate histologically the root surfaces of teeth submitted to orthodontic and surgical extrusion procedures in a dog model. Eighteen adult male dogs, divided into six groups of three dogs each, were used in the study Each animal underwent two procedures: rapid orthodontic extrusion and surgical extrusion of the maxillary lateral incisors. The animals were sacrificed to produce samples at 7, 14, 45, 90, 120, and 180 days after surgery for assessment of cross sections of the coronal, medial, and apical thirds of the treated teeth. At early time points, some active surface and inflammatory resorption was observed exclusively in the surgical extrusion group; however, samples collected at later times demonstrated functional repair of the resorption gaps in both groups. Ankylosis was observed as a minor event and was apparently of a transient nature in samples of the surgical extrusion group. The results demonstrate the importance of maintaining the periodontal ligament and cementum surface; both are vital for the prevention of root resorption. It may be postulated that orthodontic extrusion is more conservative and physiologic than surgical extrusion; however the results showed that function was restored in both groups. (Int J Periodontics Restorative Dent 2009;29:435-443.)

Survival of Dental Implants in the Cleft Area-A Retrospective Study

Objective To evaluate the survival rate of dental implants placed in the cleft area Design Retrospective study Setting Hospital for Rehabilitation of Craniofacial Anomalies, Brazil Institutional Tertiary Healthcare Center Patients 120 patients who received dental implants in the grafted cleft area in the years 1999 to 2005 Interventions Clinical data were evaluated from the records of 120 patients according to the following criteria placement grafted, cleft area, and age at surgery, age at placement of dental implants, site and dimension of implants, interval between placement of implants and the last clinical follow-up, and interval between placement and removal or indication for removal of implants Main Outcome Measures Percentage of survival rate of implants Results Mean age at placement of the bone graft was 17 6 years and 21 years at placement of implants A total of 123 cleft areas received secondary bone graft and bone graft to install implants (regraft) The mean survival rate was 34 months since placement of the implant to the last clinical follow-up and 26 months since placement of the prosthesis Seven dental implants were removed The survival rate since placement to the last clinical follow-up was 94 3% Conclusion Rehabilitation of the cleft area with dental implants is a viable and secure alternative, with good prognosis

Long-term stability of surgical-orthodontic open-bite correction

Introduction: The objective of this study was to evaluate the long-term stability of open-bite surgical-orthodontic correction. Methods: Thirty-nine patients at an initial mean age of 20.83 years were evaluated cephalometrically at pretreatment (T1), immediately after treatment (T2), and at the last recall (T3), with a mean follow-up time of 8.22 years. The surgical protocol included single-jaw or double-jaw surgery. Because the patients had different anteroposterior malocclusions, the sample was divided into a Class I and Class II (I-II) subgroup (3 Class I, 20 Class II malocclusion patients) and a Class III subgroup (16 patients). The dentoskeletal characteristics of the total sample and the subgroups were compared at T1, T2, and T3 with dependent analysis of variance (ANOVA). Results: Overbite relapse in the posttreatment period was statistically significant in the whole sample and the Class I-II subgroup. Fourteen patients of the whole sample (35.9%) had clinically significant open-bite relapse (negative overbite). Conclusions: There was a statistically significant open-bite relapse in the overall sample and in the Class I-II subgroup. The clinically significant values of long-term open-bite correction stability were 64.11%, 47.82%, and 87.50% in the overall sample, the Class I-II subgroup, and the Class III subgroup, respectively. (Am J Orthod Dentofacial Orthop 2010;138:254.e1-254.e10)

Finite Element Analysis of 2 Immediate Loading Systems in Edentulous Mandible: Rigid and Semirigid Splinting of Implants

Purpose: The objective of this study was to evaluate the stress on the cortical bone around single body dental implants supporting mandibular complete fixed denture with rigid (Neopronto System-Neodent) or semirigid splinting system (Barra Distal System-Neodent). Methods and Materials: Stress levels on several system components were analyzed through finite element analysis. Focusing on stress concentration at cortical bone around single body dental implants supporting mandibular complete fixed dentures with rigid ( Neopronto System-Neodent) or semirigid splinting system ( Barra Distal System-Neodent), after axial and oblique occlusal loading simulation, applied in the last cantilever element. Results: The results showed that semirigid implant splinting generated lower von Mises stress in the cortical bone under axial loading. Rigid implant splinting generated higher von Mises stress in the cortical bone under oblique loading. Conclusion: It was concluded that the use of a semirigid system for rehabilitation of edentulous mandibles by means of immediate implant-supported fixed complete denture is recommended, because it reduces stress concentration in the cortical bone. As a consequence, bone level is better preserved, and implant survival is improved. Nevertheless, for both situations the cortical bone integrity was protected, because the maximum stress level findings were lower than those pointed in the literature as being harmful. The maximum stress limit for cortical bone (167 MPa) represents the threshold between plastic and elastic state for a given material. Because any force is applied to an object, and there is no deformation, we can conclude that the elastic threshold was not surpassed, keeping its structural integrity. If the force is higher than the plastic threshold, the object will suffer permanent deformation. In cortical bone, this represents the beginning of bone resorption and/or remodeling processes, which, according to our simulated loading, would not occur. ( Implant Dent 2010; 19:39-49)

Early Bone Healing and Biomechanical Fixation of Dual Acid-Etched and As-Machined Implants with Healing Chambers: An Experimental Study in Dogs

Purpose: To evaluate the biomechanical fixation, bone-to-implant contact (BIC), and bone morphology of screw-type root-form implants with healing chambers with as-machined or dual acid-etched (DAE) surfaces in a canine model. Materials and Methods: The animal model included the placement of machined (n = 24) and DAE (n = 24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Following euthanasia, half of the specimens were subjected to biomechanical testing (torque to interface failure) and the other half were processed for histomorphologic and histomorphometric (%BIC) assessments. Statistical analyses were performed by one-way analysis of variance at the 95% confidence level and the Tukey post hoc test for multiple comparisons. Results: At 4 weeks, the DAE surface presented significantly higher mean values for torque to interface failure overall. A significant increase in %BIC values occurred for both groups over time. For both groups, bone formation through the classic appositional healing pathway was observed in regions where intimate contact between the implant and the osteotomy walls occurred immediately after implantation. Where contact-free spaces existed after implantation (healing chambers), an intramembranous-like healing mode with newly formed woven bone prevailed. Conclusions: In the present short-term evaluation, no differences were observed in BIC between groups; however, an increase in biomechanical fixation was seen from 2 to 4 weeks with the DAE surface. INT J ORAL MAXILLOFAC IMPLANTS 2011;26:75-82

Surgical planning for resection of an ameloblastoma and reconstruction of the mandible using a selective laser sintering 3D biomodel

Ameloblastoma is a benign locally aggressive infiltrative odontogenic lesion. It is characterized by slow growth and painless swelling. The treatment for ameloblastoma varies from curettage to en bloc resection, and the reported recurrence rates after treatment are high; the safety margin of resection is important to avoid recurrence. Advances in technology brought about great benefits in dentistry; a new generation of computed tomography scanners and 3-dimensional images enhance the surgical planning and management of maxillofacial tumors. The development of new prototyping systems provides accurate 3D biomodels on which surgery can be simulated, especially in cases of ameloblastoma, in which the safety margin is important for treatment success. A case of mandibular follicular ameloblastoma is reported where a 3D biomodel was used before and during surgery.

In vitro osteogenesis induced by cells derived from sites submitted to sinus grafting with anorganic bovine bone

Objectives: This study evaluated key parameters of the in vitro osteogenesis induced by osteoblastic cells obtained from sites submitted to sinus grafting with anorganic bovine bone (ABB) in comparison with cells derived from bone sites of the same patients. Materials and methods: In three patients, the augmentation of maxillary sinus was carried out using ABB (Bio-Oss (R)). After at least 6 months, during the surgical intervention for titanium implants placement, biopsies were taken from these areas using trephine burs (grafted group). Bone fragments, of the same patients, from sites that had not received graft were also obtained with trephine burs and used as a control group. Osteoblastic cells were obtained from grafted and control groups by enzymatic digestion and cultured under standard osteogenic condition until subconfluence. First passaged cells were cultured in 24-well culture plates. Cell adhesion was evaluated at 24 h. For proliferation and viability assay, cells were cultured for 1, 3, 7, and 10 days. Total protein content and alkaline phosphatase (ALP) activity were measured at 3, 7, 10, 14, 17, and 21 days. Cultures were stained with Alizarin red S at 21 days, for detection of mineralized matrix. Data were compared by Student`s t-test. Results: Cell adhesion and viability were not affected by cell source (P>0.05). Total protein content was greater (P<0.05) for grafted group. Cell proliferation, ALP activity, and bone-like nodule formation were all greater (P<0.05) for the control group. Conclusions: Taken together, these results indicate that the in vivo long-term contact of cells with ABB downregulates the expression of osteoblast phenotype and consequently the in vitro osteogenesis.