Franco Santoro

A novel method for banking dental pulp stem cells.

Dental pulp stem cells (DPSC), a cell type of mesenchymal origin showing high proliferation and plasticity, are an emerging source of adult stem cells offering interesting features in view of potential applications in regenerative medicine. These features prompted us to develop a new method to cryopreserve DPSC inside a whole tooth, thus avoiding the need to purify the cells before cryopreservation and reducing the initial costs and workload of tooth banking. In this study we cryopreserved 4 human deciduous whole teeth after digging micro-channels into the tooth with an Nd:YAG laser beam (laser piercing) to allow the cryopreservative to reach the dental pulp and preserve the cells at -80°C. Then, we isolated, expanded and characterized in vitro the stem cells after tooth thawing and mechanical fracture. In parallel, we characterized cells extracted from 2 teeth cryopreserved without laser piercing and from 4 non cryopreserved, non laser pierced, freshly fractured teeth. Our data demonstrate that DPSC isolated from laser pierced cryopreserved teeth show mesenchymal stem cells morphology, immunophenotype, viability and proliferation rate similar to those of cells isolated from fresh, non cryopreserved teeth, whereas significant loss of cell viability and proliferation rate was shown by cells isolated from teeth cryopreserved without laser piercing. These data support the use of this method for prospective whole tooth banking.

Determinants for success rates of temporary anchorage devices in orthodontics: a meta-analysis (n > 50)

INTRODUCTION The aim of this study was to review the literature and evaluate the failure rates and factors that affect the stability and success of temporary anchorage devices (TADs) used as orthodontic anchorage. METHODS Data were collected from electronic databases: MEDLINE database, Scopus, and Web of Knowledge. Four combinations of term were used as keywords: screw orthodontic failure, screw orthodontic success, implant orthodontic failure, and implant orthodontic success. The following selection criteria were used to select appropriate articles: articles on implants and screws used as orthodontic anchorage, data only from human subjects, studies published in English, studies with more than 50 implants/screws, and both prospective and retrospective clinical studies. RESULTS The search provided 209 abstracts about TADs used as anchorage. After reading and applying the selection criteria, 26 articles were included in the study. The data obtained were divided into two topics: which factors affected TAD success and to what degree and in how many articles they were quoted. Clinical factors were divided into three main groups: patient-related, implant-related, and management-related factors. CONCLUSIONS Although all articles included in this meta-analysis reported success rates of greater than 80 per cent, the factors determining success rates were inconsistent between the studies analysed and this made conclusions difficult.

Histomorphometric Evaluation of Anorganic Bovine Bone Coverage to Reduce Autogenous Grafts Resorption: Preliminary Results

Physiologic resorption due to remodeling processes affects autogenous corticocancellous grafts in the treatment of atrophic jawbone alveolar ridges. Such a situation in the past made overgrafting of the recipient site mandatory to get enough bone support to dental implants in order to perform a prosthetic rehabilitation. Anorganic bovine bone, conventionally used to treat alveolar bone deficiencies in implant surgery, showed a high osteoconductive property thanks to its micro and macrostructure very similar to that of human hydroxyapatite. An original technique provides for the application of a thin layer of anorganic bovine bone granules and a collagen membrane on the top of the corticocancellous onlay bone grafts to reduce in a remarkable way the graft resorption due to remodeling. The results of a clinical prospective study and a histomorphometric analysis done on autogenous grafts harvested from the iliac crest showed that the proposed technique is able to maintain the original bone volume of the corticocancellous blocks.

Osseointegration and guided bone regeneration in ectodermal dysplasia patients.

Dental and surgical implant treatment for patients affected by ectodermal dysplasia syndrome can be very complicated. The guided bone regeneration (GBR) membrane technique together with bone grafting is used to facilitate the placement of osseointegrated implants in a prosthetically guided position. Two groups with the same bony anatomical features were assessed. The first consisted of 13 ectodermal dysplasia patients in whom 66 implants with bone grafts and membranes were inserted. In the second control group, 120 implants with GBR were placed in 20 patients. The implants were assessed at the second stage of surgery, and at a follow-up after 1, 2, and 3 years of functional loading. There was no statistically significant difference in the osseointegration rate between the two groups. Despite the anatomical defects associated with the decreased occlusal vertical dimension and the reduced edentulous alveolar ridges, both in height and width, osseointegrated implants together with GBR and bone grafts can be used successfully in patients with ectodermal dysplasia syndrome.

Histomorphometrical evaluation of fresh frozen bone allografts for alveolar bone reconstruction: preliminary cases comparing femoral head with iliac crest grafts.

PURPOSE In the past few years, the use of fresh frozen bone (FFB) grafts has significantly increased. The aim of this study was to evaluate the reconstruction of alveolar bone using femoral head and iliac crest FFB grafts. MATERIALS AND METHODS The study included 10 patients who need endosseous implant insertion in severe atrophic maxillae. The patients were treated with FFB grafts collected from the femoral head or iliac crest. Bone regeneration was evaluated 6 months after surgery by macroscopic and microscopic analyses. RESULTS Our results showed good regenerative capacity, both with the FFB from the femoral head and iliac crest. In particular, similar percentages of new-bone formation and graft residual were observed, whereas differences between the percentage of total bone (higher for the iliac crest) and the percentage of non-mineralized tissue (higher for the femoral head) were present. A significantly higher percentage of CD34-positive vessels in the FFB allograft from the femoral head than in the iliac crest were observed. CONCLUSIONS These findings suggest that FFB allografts could represent a reliable option in oral and maxillofacial surgery. Nevertheless, differences between the use of femoral head or iliac crest bone allografts linked with their different structures should be considered for a more effective surgery.

A Four-Year Survival Rate Multicenter Prospective Clinical Study on 377 Implants: Correlations Between Implant Insertion Torque, Diameter, and Bone Quality.

The purpose of this study was to evaluate the survival rate and incidence of prosthetic complications in 377 implants with a double octagon connection. Furthermore, the correlations among implant dimensions (diameter and length), bone quality, and insertion torque were investigated. A 4-year multicenter prospective clinical study was designed to evaluate the survival rate of 377 dental implants inserted in 189 patients between January 2004 and April 2010. After an average follow-up of 46 months, the implant survival rate was 99.7%, and the incidence of complication was 0.53%. Moreover, insertion torque was statistically related in a significant way to implant diameter. The connection system seemed to reduce the risk that the prosthetic component screw would loosen. Within the limits of this study, it was observed that a wider diameter corresponded to a higher implant primary stability. Implant length did not seem to be critical in obtaining higher primary stability.

Do ultrasonic dental scalers interfere with implantable cardioverter defibrillators? An in vivo investigation

OBJECTIVES To test the in vivo effects of an ultrasonic dental scaler on various implanted cardioverter defibrillator (ICD) models. METHODS 12 consecutive patients with ICDs had continuous both electrocardiogram monitoring and device interrogation to detect interferences during the use of an ultrasonic dental scaler. RESULTS No interferences were detected by any ICD. Evaluation of the electrocardiograms for each patient failed to show any abnormalities in pacing during testing. CONCLUSION The results of this study suggest that the routinary clinic use of piezoelectric dental scalers do not interfere with the functioning of any of the tested ICDs. CLINICAL SIGNIFICANCE Ultrasonic dental scalers have been suspected of electromagnetic interference (EMI) with the normal functioning of ICDs and the use of this type of equipment for patients with these devices has been controversial. This is the first in vivo study to investigate EMI of ICD activity during the operation with ultrasonic dental scaler.

Long-Term Retrospective Evaluation of Dental Implants Placed in Resorbed Jaws Reconstructed With Appositional Fresh-Frozen Bone Allografts.

Introduction:The aim of this study was to evaluate the outcome of fresh-frozen bone allografts in preprosthetic surgery for implant placement purposes. Materials and Methods:The cohort comprised 45 patients treated with fresh-frozen bone block grafts and dental implants. Clinical and radiological evaluations were performed to evaluate the survival rate. The data were statistically analyzed with the Kaplan-Meier estimator to assess the influence of possible predictors of implant failure on survival. Results:Overall, 262 implants were retrospectively analyzed. The survival rate was 90.84% over a mean follow-up of 50 months. Comparing the donor site and the position of the implants, no statistically significant differences could be detected (P = 0.7194 and P = 0.2901, respectively), whereas sex resulted in a marginally statistically significant difference (P = 0.0581). When considering age categorized on the median value (⩽55/>55 years), age resulted in a statistically significant difference (P = 0.0340), with higher failures found in older people. Conclusion:Implant loss was strictly related to the lack of primary osseointegration. Female sex and old age were found to be risk factors, which could negatively influence implant survival.

Measuring effectiveness of orthognathic surgery by electromyography: A restrospective clinical study

BACKGROUND This study investigates retrospectively if the initial electromyography (EMG) status of patients who underwent orthognathic surgery correlates with the extent of postsurgical EMG functional recovery. METHODS Clinical records concerning 20 patients who underwent Le Fort I and/or sagittal osteotomy of the mandibular ramus to correct skeletal dental class III malocclusions were retrieved and presurgical and postsurgical EMG data were analyzed and compared. Additionally, postsurgical EMG recovery was compared with that of a set of healthy, not surgically treated class I patients, with no sign of disorders affecting the temporomandibular joint (TMJ). Finally, the effect of six independent variables (age, sex, time from surgery, extent of segment re-positioning, malocclusion class, upper jaw repositioning) on muscular recovery was investigated by means of correlation analysis. RESULTS A significant increase of the average EMG activity after orthognathic corrective surgery was observed (P=0.01). The postsurgical increase of EMG values showed a negative correlation trend with those collected before surgery (r=-0.38, clenching on teeth; r=-0.33, clenching on cotton rolls). None of the independent variables had any effect on the postsurgical outcome. CONCLUSIONS Orthognathic surgery improves the muscular activity of patients who present skeletal dental class III malocclusions. This improvement can be objectively assessed with EMG measurements. Patients who benefit more from orthognathic surgery seem to be those displaying the lowest presurgical EMG activity.