Danilo Alessio Di Stefano

Alveolar Ridge Regeneration with Equine Spongy Bone: A Clinical, Histological, and Immunohistochemical Case Series

BACKGROUND In the case of localized ridge atrophy, a ridge augmentation procedure, with the use of bone substitutes and barrier membranes, may then be necessary. PURPOSE The aim of the present study was a clinical, histological, and immunohistochemical evaluation of an equine spongy bone in alveolar ridge augmentation procedures. MATERIALS AND METHODS Five patients showing horizontal mandibular ridge defects participated in this study. A ridge augmentation was performed through an onlay apposition of equine bone covered by a titanium-reinforced membrane. After 6 months of healing, five bone cores from nonaugmented sites (control) and five from augmented sites (test) were retrieved. RESULTS In test sites, no postoperative complications occurred. Horizontal bone width increased from 24 to 37 mm. In control sites, the newly formed bone represented 33%, and in test sites, 35% of the total area. The mean value of the microvessel density was 25.6 +/- 3.425 per mm(2) in controls, while 33.3 +/- 2.5 vessels per mm(2) in the test sites were found (p < .05). Both groups showed a high intensity (++) of vascular endothelial growth factor expression in the newly formed bone, while a low intensity (+) was found in the mature bone. CONCLUSION Equine bone appeared to be biocompatible and to be associated with new vessel ingrowth. Within the limits of the small sample size, the present study indicated that equine bone could be used in mandibular ridge augmentations.

Prevention and treatment of postoperative infections after sinus elevation surgery: clinical consensus and recommendations.

Introduction. Maxillary sinus surgery is a reliable and predictable treatment option for the prosthetic rehabilitation of the atrophic maxilla. Nevertheless, these interventions are not riskless of postoperative complications with respect to implant positioning in pristine bone. Aim. The aim of this paper is to report the results of a clinical consensus of experts (periodontists, implantologists, maxillofacial surgeons, ENT, and microbiology specialists) on several clinical questions and to give clinical recommendations on how to prevent, diagnose, and treat postoperative infections. Materials and Methods. A panel of experts in different fields of dentistry and medicine, after having reviewed the available literature on the topic and taking into account their long-standing clinical experience, gave their response to a series of clinical questions and reached a consensus. Results and Conclusion. The incidence of postop infections is relatively low (2%–5.6%). A multidisciplinary approach is advisable. A list of clinical recommendation are given.

Correlation between Initial BIC and the Insertion Torque/Depth Integral Recorded with an Instantaneous Torque-Measuring Implant Motor: An in vivo Study

BACKGROUND Quantitative intraoperative evaluation of bone quality at implant placement site and postinsertion implant primary stability assessment are two key parameters to perform implant-supported rehabilitation properly. A novel micromotor has been recently introduced allowing to measure bone density at implant placement site and to record implant insertion-related parameters, such as the instantaneous, average and peak insertion torque values, and the insertion torque/depth integral. PURPOSE The aim of this study was to investigate in vivo if any correlation existed between initial bone-to-implant contact (BIC) and bone density and integral values recorded with the instrument. MATERIALS AND METHODS Twenty-five patients seeking for implant-supported rehabilitation of edentulous areas were consecutively treated. Before implant placement, bone density at the insertion site was measured. For each patient, an undersized 3.3 × 8-mm implant was placed, recording the insertion torque/depth integral values. After 15 minutes, the undersized implant was retrieved with a 0.5 mm-thick layer of bone surrounding it. Standard implants were consequently placed. Retrieved implants were analyzed for initial BIC quantification after fixation, dehydration, acrylic resin embedment, sections cutting and grinding, and toluidine-blue and acid fuchsine staining. Correlation between initial BIC values, bone density at the insertion site, and the torque/depth integral values was investigated by linear regression analysis. RESULTS A significant linear correlation was found to exist between initial BIC and (a) bone density at the insertion site (R = 0.96, explained variance R(2)  = 0.92) and (b) torque/depth integral at placement (R = 0.81, explained variance R(2)  = 0.66). CONCLUSIONS The system provided quantitative, reliable data correlating significantly with immediate postinsertion initial BIC, and could therefore represent a valuable tool both for clinical research and for the oral implantologist in his/her daily clinical practice.

Sinus lift with autologous bone alone or in addition to equine bone: an immunohistochemical study in man.

Purpose:The aim of the present study was to perform a comparative histological and immunohistochemical evaluation of microvessel density, vascular endothelial growth factor, and nitric oxide synthase (NOS) expression in sinus augmentation using autologous bone alone or in combination with equine bone. Materials and Methods:Sixteen patients underwent sinus augmentation with autologous bone and a 50:50 mixture of autologous and equine bone. Control cores were harvested from preexisting nonaugmented bone under the sinus floor. The specimens were processed for immunohistochemistry. Results:The greatest values of microvessel density were found in the sites grafted with autologous bone with significant differences between control versus autologous group (P < 0.01) and control versus autologous + equine group (P < 0.01). The higher and lower intensities of vascular endothelial growth factor and NOS3 expression were prevalent in the sites grafted with autologous bone with significant differences with the controls (P < 0.05). No significant differences (P > 0.05) were found in the NOS1 expression among the groups. Conclusion:The results obtained showed that the mixture of autologous and equine bone was biocompatible, and its use was associated with new blood vessels ingrowth during healing, which has been found to be extremely important for bone formation.

Histomorphometric Comparison of Enzyme-Deantigenic Equine Bone and Anorganic Bovine Bone in Sinus Augmentation: A Randomized Clinical Trial with 3-Year Follow-Up

PURPOSE To conduct a histomorphometric investigation comparing the use of enzyme-deantigenic equine bone (EDEB) and anorganic bovine bone (ABB) for maxillary sinus augmentation. MATERIALS AND METHODS Forty patients with Cawood Class V atrophic ridges who required maxillary sinus augmentation randomly received EDEB (n = 20) or ABB (n = 20) granules. Six months later, biopsy specimens were obtained, and implants were placed. Bone specimens were subjected to histomorphometric analysis, and newly formed bone (NFB) and residual biomaterial (RB) percentages were calculated. Patients were followed up for 3 years after definitive prosthetic rehabilitation, and implant success and survival rates were determined according to the criteria of Albrektsson and Zarb. RESULTS All patients healed uneventfully. Histomorphometric results for the EDEB were as follows: NFB = 46.86% ± 12.81% and RB = 11.05% ± 9.27%. For ABB, they were: NFB = 25.12% ± 7.25% and RB = 28.65% ± 9.70%. The difference was significant at a .05 level of confidence both for NFB and RB. At the 3-year follow-up, the implant survival rate was identical in the two groups (100%). CONCLUSION Grafting with EDEB resulted in a greater quantity of NFB at implant insertion. No significant clinical differences were observed between the two patient groups at the 3-year follow-up. EDEB was as effective as ABB for sinus augmentation.

Bone formation following sinus augmentation with an equine-derived bone graft: A retrospective histologic and histomorphometric study with 36-month follow-up

PURPOSE The aim of this study was to investigate bone formation over time following maxillary sinus augmentation with an enzyme-deantigenic, bone collagen-preserving equine bone graft by retrospective assessment of histomorphometric data. MATERIALS AND METHODS Records of patients with atrophic ridges who underwent maxillary sinus augmentation with the enzyme-deantigenic equine bone graft and two-step implant placement between 3 and 12 months after the sinus-augmentation surgery were assessed retrospectively. The histomorphometric data were clustered in three classes according to time of collection from the augmentation surgery and analyzed to assess newly formed bone deposition and residual biomaterial degradation rates. Data concerning the 36-month clinical follow-up were also assessed. RESULTS Records of 77 patients and 115 biopsy specimens were retrieved, and histomorphometric data were clustered (3 to 5 months, n = 33; 6 to 8 months, n = 57; 9 to 12 months, n = 25). Mean minimum atrophic ridge thickness was 4.9 ± 0.5 mm (range, 4.0 to 7.1 mm). The amount of newly formed bone and residual biomaterial did not significantly differ among the three clusters. Qualitative analysis showed a denser trabecular structure in late (> 8 months) samples. At the 36-month clinical follow-up, no differences were found among the implant success rates in the three groups, according to the Albrektsson and Zarb criteria for success. The overall implant success rate was 98.3%. CONCLUSION Based upon this retrospective human study of 77 patients with 4 to 7 mm of residual bone, when enzyme-deantigenic equine bone is used for sinus augmentation, new bone formation occurs at an early time (< 3 months) after the grafting, and implant placement can be safely carried out as soon as 3 to 5 months after the augmentation surgery.

The effect of undersizing and tapping on bone to implant contact and implant primary stability: A histomorphometric study on bovine ribs

PURPOSE Implant site preparation may be adjusted to achieve the maximum possible primary stability. The aim of this investigation was to study the relation among bone-to-implant contact at insertion, bone density, and implant primary stability intra-operatively measured by a torque-measuring implant motor, when implant sites were undersized or tapped. MATERIALS AND METHODS Undersized (n=14), standard (n=13), and tapped (n=13) implant sites were prepared on 9 segments of bovine ribs. After measuring bone density using the implant motor, 40 implants were placed, and their primary stability assessed by measuring the integral of the torque-depth insertion curve. Bovine ribs were then processed histologically, the bone-to-implant contact measured and statistically correlated to bone density and the integral. RESULTS Bone-to-implant contact and the integral of the torque-depth curve were significantly greater for undersized sites than tapped sites. Moreover, a correlation between bone to implant contact, the integral and bone density was found under all preparation conditions. The slope of the bone-to-implant/density and integral/density lines was significantly greater for undersized sites, while those corresponding to standard prepared and tapped sites did not differ significantly. CONCLUSION The integral of the torque-depth curve provided reliable information about bone-to-implant contact and primary implant stability even in tapped or undersized sites. The linear relations found among the parameters suggests a connection between extent and modality of undersizing and the corresponding increase of the integral and, consequently, of primary stability. These results might help the physician determine the extent of undersizing needed to achieve the proper implant primary stability, according to the planned loading protocol.

The insertion torque-depth curve integral as a measure of implant primary stability: An in vitro study on polyurethane foam blocks

Statement of problem. Recent research has shown that dynamic parameters correlate with insertion energy—that is, the total work needed to place an implant into its site—might convey more reliable information concerning immediate implant primary stability at insertion than the commonly used insertion torque (IT), the reverse torque (RT), or the implant stability quotient (ISQ). Yet knowledge on these dynamic parameters is still limited. Purpose. The purpose of this in vitro study was to evaluate whether an energy‐related parameter, the torque‐depth curve integral (I), could be a reliable measure of primary stability. This was done by assessing if (I) measurement was operator‐independent, by investigating its correlation with other known primary stability parameters (IT, RT, or ISQ) by quantifying the (I) average error and correlating (I), IT, RT, and ISQ variations with bone density. Material and methods. Five operators placed 200 implants in polyurethane foam blocks of different densities using a micromotor that calculated the (I) during implant placement. Primary implant stability was assessed by measuring the ISQ, IT, and RT. ANOVA tests were used to evaluate whether measurements were operator independent (P>.05 in all cases). A correlation analysis was performed between (I) and IT, ISQ, and RT. The (I) average error was calculated and compared with that of the other parameters by ANOVA. (I)‐density, IT‐density, ISQ‐density, and RT‐density plots were drawn, and their slopes were compared by ANCOVA. Results. The (I) measurements were operator independent and correlated with IT, ISQ, and RT. The average error of these parameters was not significantly different (P>.05 in all cases). The (I)‐density, IT‐density, ISQ‐density, and RT‐density curves were linear in the 0.16 to 0.49 g/cm3 range, with the (I)‐density curves having a significantly greater slope than those regarding the other parameters (P≤.001 in all cases). Conclusions. The torque‐depth curve integral (I) provides a reliable assessment of primary stability and shows a greater sensitivity to density variations than other known primary stability parameters.

Evaluation of Peri-implant Bone Stress on D1 Bone Using a Computerized Torque-Measuring Implant Motor: A Study on Photoelastic Resin Blocks

PURPOSE Recently, a torque-measuring micromotor that calculates the integral (I) of torque-depth curve at implant insertion was developed. This device was used to investigate the correlation between (I) and mechanical stress in photoelastic resin blocks with the density of D1 bone. MATERIALS AND METHODS Using the micromotor, 40 implants (3.75 × 12 mm) were placed in 40 D1 blocks that had been prepared in four different ways. Four groups of 10 blocks each were prepared according to tunnel length (12 or 14 mm) and debris removal (yes or no). After insertion, peri-implant mechanical stress and its correlation with (I) were assessed by photoelastic and linear regression analysis, respectively. Analysis of variance (ANOVA) and Kruskal-Wallis tests investigated differences in mechanical stress patterns and dynamic parameters among the groups. RESULTS (I) significantly correlated with mechanical stress in D1 resin under all conditions, except for 12-mm implant sites still containing debris. The correlation was significant concerning the whole dataset (r = 0.979) and separately for the coronal (r = 0.940), middle (r = 0.964), and apical (r = 0.948) portions of the implants. Peak torque did not correlate significantly with peri-implant mechanical stress. Longer implant sites and debris removal were significantly associated with lower peri-implant mechanical stress. CONCLUSION (I) provides a reliable measure of mechanical stress in D1 bone during implant placement. Preparation of longer osteotomies and routine removal of all debris might reduce peri-implant bone stress significantly.