Distribution of Trabecular Bone Density in the Maxilla and Mandible.

INTRODUCTION: Implant osseointegration is strongly influenced by the bone quality at the implant insertion site. The present work aims to create distribution diagrams showing the average bone density at each position within the jaws. MATERIALS AND METHODS: Data were retrospectively collected from 4 oral surgeons who sought bone-density measurements during implant placement using a torque-measuring implant micromotor. Statistical analyses were performed to investigate whether bone density correlated with the patients' sex and age and whether the bone-density values at different positions within each arch correlated to each other. RESULTS: Records of 2408 patients and 6060 bone-density readings were retrieved, and density distribution diagrams were created. Density values showed a significant variation within subjects. Within the same jaw, density between adjacent positions showed significant differences. Density at a given position correlated significantly with that at the other positions in most cases. Bone density was significantly lower in women than in men; no significant correlation was found between bone density and the patient age. CONCLUSIONS: Bone density of patients displays significant interindividual variation, thus meaningful assessment must be conducted on a patient-by-patient basis.

Immediate Postextractive Implants With and Without Bone Graft: 3-year Follow-up Results From a Multicenter Controlled Randomized Trial.

PURPOSE: To evaluate the outcome of single postextraction immediate implants placed with and without bone grafts in the esthetic maxillary premolar area for 3-year follow-up after loading. MATERIAL AND METHODS: After tooth extraction, 102 patients received 115 immediate dental implants. Patients were randomly allocated to immediate implant placement with (group A: 51) or without (group B: 51) anorganic bovine bone and resorbable collagen barrier. RESULTS: After 3 years (T36), 1 implant failed in each group. Thirty-seven patients showed inflammation and bleeding, 19 mucositis, and 2 periimplantitis. Statistical significant association was found between BOP and mucositis at T12 (P < 0.0005) and T36 (P < 0.0005). The mesial bone level was -0.61 mm in group B and -1.01 mm in group A (P < 0.001). The group B distal bone level was -0.71 mm and -1.12 mm in group A (P < 0.005). Group B's buccal mean probing was increased (+0.40 mm) than group A (+0.36 mm). Group B's palatal mean value was higher (+0.54 mm) than group A (+0.38 mm). No statistically significant differences were found between the 2 groups. However, the Pink Esthetic Score and patient satisfaction were higher in group B than A (P < 0.001). CONCLUSIONS: The use of anorganic bovine bone substitute with a resorbable collagen barrier in immediate postextractive implants seems to improve the esthetic outcomes after a 3-year follow-up.

Equine and porcine bone substitutes in maxillary sinus augmentation: a histological and immunohistochemical analysis of VEGF expression.

The aim of this work was to investigate the morphological structure and the expression of vascular endothelial growth factor (VEGF) after maxillary sinus augmentation through equine and porcine bone substitutes in humans. Ten patients showing edentulous posterior maxilla underwent maxillary sinus augmentation through particulate equine bone substitute and 10 patients through particulate porcine bone substitute. At the moment of implants insertion, 6 months after grafting, bone specimens were withdrawn and processed for morphological and immunohistochemical analyses. Notwithstanding the almost comparable clinical performances of both bone substitutes, histological results showed a better integration when an equine bone substitute was used compared to a porcine one. In particular, evident signs of particles resorption were observed in equine bone substitute group specimens compared to porcine ones. Immunohistochemical analysis showed a statistically significant increase of VEGF expression in equine compared to porcine bone substitute group specimens. These results showed both bone substitutes to achieve comparable clinical performance, indicating their successful use for bone regenerative procedures. However, in the same experimental time, equine group specimens showed evident resorption phenomena, whereas no or little signs of resorption were evident in the porcine group specimens. However, a more rapid and intense vascularization was achieved in equine bone substitute group, as demonstrated by immunohistochemical analysis for VEGF expression. Even if differences in vascularization significantly affect the clinical performance of a heterologous bone substitute, its ability to be resorbed is also very important in influencing long-term integration and long-term predictability of implant-prosthetic rehabilitation in regenerated sites.

Indications for implant-supported rehabilitation of the posterior atrophic maxilla: A multidisciplinary consensus among experts in the field utilising the modified Delphi method.

PURPOSE: To establish consensus-driven guidelines that could support the clinical decision-making process for implant-supported rehabilitation of the posterior atrophic maxilla and ultimately improve long-term treatment outcomes and patient satisfaction. MATERIALS AND METHODS: A total of 33 participants were enrolled (18 active members of the Italian Academy of Osseointegration and 15 international experts). Based on the available evidence, the development group discussed and proposed an initial list of 20 statements, which were later evalu-ated by all participants. After the forms were completed, the responses were sent for blinded ana-lysis. In most cases, when a consensus was not reached, the statements were rephrased and sent to the participants for another round of evaluation. Three rounds were planned. RESULTS: After the first round of voting, participants came close to reaching a consensus on six statements, but no consensus was achieved for the other fourteen. Following this, nineteen statements were rephrased and sent to participants again for the second round of voting, after which a consensus was reached for six statements and almost reached for three statements, but no consensus was achieved for the other ten. All 13 statements upon which no consensus was reached were rephrased and included in the third round. After this round, a consensus was achieved for an additional nine statements and almost achieved for three statements, but no consensus was reached for the remaining statement. CONCLUSION: This Delphi consensus highlights the importance of accurate preoperative planning, taking into consideration the maxillomandibular relationship to meet the functional and aesthetic requirements of the final restoration. Emphasis is placed on the role played by the sinus bony walls and floor in providing essential elements for bone formation, and on evaluation of bucco-palatal sinus width for choosing between lateral and transcrestal sinus floor elevation. Tilted and trans-sinus implants are considered viable options, whereas caution is advised when placing pterygoid implants. Zygomatic implants are seen as a potential option in specific cases, such as for completely edentulous elderly or oncological patients, for whom conventional alternatives are unsuitable.

Histological evaluation of fresh frozen bone integration at different experimental times.

The aim of this work was to investigate, through histological evaluation, the in vivo behavior of fresh frozen bone (FFB) used as particulate bone substitute in intraoral regenerative procedures. A total of 10 patients (group 1) received particulate FFB graft for bone regeneration in postextractive sockets, and 10 (group 2) underwent maxillary sinus augmentation by using the same bone substitute as filling. Fresh frozen bone was supplied from the Tissue Bank of the Veneto Region, Treviso Section.Healing was uneventful for all the patients and was monitored by periodical radiographs. Patients were scheduled for implant insertion according to the radiographic aspect. However, the mean healing time for group 1 was 45 days, whereas for group 2 patients, it was 100 days. At the moment of implant insertion, bone specimens were collected at the site of implant placement, from both groups and processed for histological analysis.Histological analysis after hematoxylin-eosin staining obtained from group 1 patients showed the presence of newly formed bone tissue, still well distinguishable from the grafted bone substitute. In samples from group 2 patients, a better integration could be recognized associated with active bone remodeling phenomena.These results showed a good integration of the considered FFB graft within the host tissue both at 45 and 100 days after grafting, displaying this biomaterial as suitable for preimplant regenerative procedures.

A comparison of bovine bone and hydroxyapatite scaffolds during initial bone regeneration: an in vitro evaluation.

OBJECTIVES: To evaluate the different behavior of 3-dimensional biomaterial scaffolds-Bovine Bone (BB; Bio-Oss) and Hydroxyapatite (HA; ENGIpore)-during initial bone healing and development. MATERIALS AND METHODS: Human dental papilla stem cells (hDPaSCs) were selected with FACsorter cytofluorimetric analysis, cultured with osteogenic medium, and analyzed with Alizarin red stained after differentiation. The obtained osteoblast-like cells (OCs) were cultured with BB and HA. alkaline phosphatase (ALP), OC, MEPE, and runt-related transcription factor 2 (RUNX2) expression markers were investigated performing Western blot and reverse transcription-polymerase chain reaction (RT-PCR) analysis. After 40 days, samples were analyzed by light and electron microscopy. RESULTS: All the samples showed high in vitro biocompatibility and qualitative differences of OCs adhesion. RT-PCR and Western blot data exhibited similar marker rate, but ALP, OC, MEPE, and RUNX2expression, during initial healing and bone regeneration phase, was higher and faster in human dental papilla onto BB than in HA scaffolds. In biomaterials growth, RUNX2 seems to play an important role as a key regulator in human OCs from dental papilla bone development. CONCLUSION: Different surface BB scaffold characteristics seem to play a critical role in OCs differentiation showing different time of bone regeneration morphological characteristics as well as higher and faster levels of all observed markers.

Sinus floor elevation with crestal approach and immediately loaded post-extraction implants.

Alveolar ridges in the posterior maxilla are often compromised by reduced bone volume. This anatomic condition often limits dental implant placement, mostly because of limited vertical bone availability without prior or simultaneous sinus augmentation. When at least 5 mm of residual bone are present, osteotome techniques are used as a less invasive alternative to the lateral window approach to increase bone volume in the posterior posterior region of the maxillary jaw. Implants are generally placed simultaneously for four to six months after performing osteotome-mediated sinus floor elevation, depending upon the residual crestal bone remaining beneath the sinus floor. However, unlike common indications, in order to shorten the treatment period, this report aims to show a challenging case where, through a thorough surgical protocol, two compromised maxillary teeth were replaced by two immediately loaded post-extraction implants contextually to an osteotome-mediated sinus floor elevation.

Immunohistochemical analysis of matrix metalloproteinase-9, vascular endothelial growth factor, bone sialoprotein and i-nitric oxide synthase in calvaria vs. iliac crest bone grafts.

OBJECTIVES: The aim of this study was to investigate, in parallel to clinical and histological modifications, the expression of specific proteins involved in different extraoral autologous bone grafts integration in humans. MATERIAL AND METHODS: Patients needing oral rehabilitation of posterior maxilla, with inadequate bone volume for implant placement, received bone grafts from calvaria (Group 1) and iliac crest (Group 2), respectively. From five patients from each group, with a total of 10 subjects, bone biopsy specimens were collected at two different experimental time points: at bone blocks withdrawal for grafting (T0), from donor sites, and after 4 months, from reconstructed sites. Samples were processed for light microscope and immunohistochemical analyses to evaluate MMP9, VEGF, BSP, iNOS expression. RESULTS: Morphological analysis of T0 calvaria evidenced areas of extracellular matrix, uniformly stained and organized in concentric mineralized lamellae edging few vascular canals, while T0 iliac crest showed greater cellularity compared to calvaria, with rare mineralized areas, surrounding wide bone marrow lacunae. In T1, Group 1 samples showed large areas of extracellular matrix, uniformly stained, at the same time as Group 2 samples disclosed few areas of mineralized tissue. Although no significant differences were found in proteins expression among calvaria and iliac crest T0 samples, MMP9, VEGF and BSP expression at T1 were discovered higher in Group 1 samples than in Group 2 ones, while iNOS expression increased in Group 2 samples compared to the others. In any group, molecules expression increased passing from T0 to T1. CONCLUSION: These findings suggested that, even though clinically both extraoral sources of autologous bone could be considered suitable for grafting in case of large oral rehabilitation, some differences might be detected microscopically and biologically. Calvaria bone graft seemed to enhance not only the quantity of bone tissue at the defect site, but also its quality, better than iliac crest bone do. Then, while both grafts appeared to promote a suitable neoangiogenesis, as showed by morphological analysis and by MMP9 and VEGF expression, in terms of new bone formation and lack of occurrence of inflammatory events, calvaria could be considered a more suitable donor site for bone grafts.

Radiographic and Histomorphologic Evaluation of the Maxillary Bone after Crestal Mini Sinus Lift Using Absorbable Collagen-Retrospective Evaluation.

BACKGROUND: After tooth extraction, the alveolar bone loses volume in height and width over time, meaning that reconstructive procedures may be necessary to perform implant placement. In the maxilla, to increase the bone volume, a mini-invasive surgery, such as a sinus lift using the crestal approach, could be performed. METHODS: A crestal approach was used in this study to perform the sinus lift, fracturing the bone and inserting collagen (Condress®). The single dental implant was placed in the healed bone after six months. RESULTS: The newly formed bone was histologically analyzed after healing. Histomorphological analyses confirmed the quality of the new bone formation even without graft biomaterials. This is probably due to the enlargement of the space, meaning more vascularization and stabilization of the coagulum. CONCLUSION: Using just collagen could be sufficient to induce proper new bone formation in particular clinical situations, with a minimally invasive surgery to perform a sinus lift.

Radiographic protrusion of dental implants in the maxillary sinus and nasal fossae: A multidisciplinary consensus utilising the modified Delphi method.

The aim of the present study was to generate an international and multidisciplinary consensus on the clinical management of implant protrusion into the maxillary sinuses and nasal fossae. A total of 31 experts participated, 23 of whom were experts in implantology (periodontologists, maxillofacial surgeons and implantologists), 6 were otolaryngologists and 2 were radiologists. All the participants were informed of the current scientific knowledge on the topic based on a systematic search of the literature. A list of statements was created and divided into three surveys: one for all participants, one for implant providers and radiologists and one for otolaryngologists and radiologists. A consensus was reached on 15 out of 17 statements. According to the participants, osseointegrated implants protruding radiographically into the maxillary sinus or nasal fossae require as much monitoring and maintenance as implants fully covered by bone. In the event of symptoms of sinusitis, collaboration between implant providers and otolaryngologists is required. Implant removal should be considered only after pharmacological and surgical management of sinusitis have failed.

Long-term evaluation of maxillary reconstruction by iliac bone graft.

The aim of this study was to analyze histologic and immunohistochemical modifications taking place in maxillary sites reconstructed by iliac crest bone grafts, 4 months (T1) and 10 years (T2) after grafting, in comparison to native iliac crest bone (T0).By light microscopy, T1 samples showed well-organized osteoblasts and extracellular matrix (ECM), and surrounding areas of connective tissue where a discrete number of blood vessels can be distinguished. Samples obtained from reconstructed areas after a long period of follow-up (T2) were characterized by uniform mineralized ECM with cavities containing osteocytes, whereas T0 samples disclosed both mineralized matrix and bone marrow. Matrix metalloproteinase 2 (MMP-2), vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS), and bone sialoprotein (BSP) expressions were investigated by immunohistochemical analysis. Both MMP-2 and VEGF showed significantly increased expression in T1, with respect to T0, and lowered in T2. Otherwise, BSP expression, which was elevated in native iliac crest bone (T0), was deeply decreased in T1 and T2 samples. Moreover, changes in iNOS expression and in apoptotic cell nuclei percentages (TUNEL analysis) seemed to have a similar trend, increasing in T1 and lowering in T2.After a period of 4 months, iliac crest bone graft-reconstructed sites show mineralizing nuclei not strongly represented, as suggested by BSP lower expression, whereas new blood vessel proliferation and active remodeling phenomena are developing. After a long period from the grafting (T2), BSP expression decreases along with MMP-2, VEGF, and iNOS, suggesting the presence of only weak arrangement phenomena of the graft.

A retrospective preliminary histomorphometric and clinical investigation on sinus augmentation using enzyme-deantigenic, collagen-preserving equine bone granules and plasma rich in growth factors.

BACKGROUND: Enzyme-deantigenic equine bone (EDEB) is a substitute of autogenous bone. Mixing it with plasma rich in growth factors (PRGF) seems a viable option to achieve enhanced bone formation in alveolar bone augmentation surgeries. This retrospective study aims to first report the histomorphometric and clinical outcomes achieved when using the EDEB/PRGF mixture for performing sinus augmentation procedures followed by delayed implant placement. MATERIALS AND METHODS: Records of 11 patients who underwent 14 sinus augmentation surgeries using EDEB/PRGF followed by delayed implant placement were retrospectively collected and analyzed to assess histomorphometric data concerning newly formed bone (NFB) and residual biomaterial (RB) recorded at implant placement, marginal bone loss (MBL) values of implants placed in the augmented sinuses, and implant and prosthetic success and survival rates. RESULTS: At 5.6 ± 1.1 months after grafting, NFB and RB were 34.0 ± 9.1% and 11.3 ± 2.2% respectively, and no histologic signs of inflammation or immune reaction were observed in any of the 34 bone biopsies being collected. Further, 86.5 ± 4.3 months after implant placement, MBL was 0.40 ± 0.07 mm. No implant or prosthesis failed, and the implant success and survival rates were 100% CONCLUSIONS: Within the limitations of the present study, grafting EDEB/PRGF for lateral sinus augmentation and delayed implant placement seems to be safe. Compared to published data concerning EDEB alone, results of the present study do not suggest that the EDEB/PRGF combination may provide a histomorphometric or medium-/long-term clinical advantage.

Digital Smile Designed Computer-Aided Surgery versus Traditional Workflow in "All on Four" Rehabilitations: A Randomized Clinical Trial with 4-Years Follow-Up.

The aim of the present study was to evaluate and compare the traditional "All on Four" technique with digital smile designed computer-aided "All on Four" rehabilitation; with a 4-years follow-up. The protocol was applied to a total of 50 patients randomly recruited and divided in two groups. Digital protocol allows for a completely virtual planning of the exact position of the fixtures, which allows one to perform a flapless surgery procedure with great accuracy (mini-invasive surgery) and also it is possible to use virtually planned prostheses realized with Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) (methods for an immediate loading of the implants. After 4 years from the treatments 98% of success were obtained for the group of patients treated with the traditional protocol and 100% for the digital protocol. At each time interval a significant difference in peri-implant crestal bone loss between the two groups was detected; with an average Marginal Bone Loss (MBL) at 4 years of 1.12 ± 0.26 mm in the traditional group and 0.83 ± 0.11 mm in the digital group. Patients belonging to the digital group have judged the immediate loading (92%), digital smile preview (93%), the mock-up test (98%) and guided surgery (94%) as very effective. All patients treated with a digital method reported lower values of during-surgery and post-surgery pain compared to patients rehabilitated using traditional treatment. In conclusion, the totally digital protocol described in the present study represents a valid therapeutic alternative to the traditional "All on Four" protocol for implant-supported rehabilitations of edentulous dental arches.

Marginal Bone Resorption Around Dental Implants Placed in Alveolar Socket Preserved Sites: A 5 Years Follow-up Study.

AIM: The present study evaluated the clinical and radiological stability of hard and soft tissues following alveolar socket preservation (ASP) procedure with a follow-up of 5 year from implant insertion. MATERIALS AND METHODS: The initial sample consisted of seven patients who underwent single tooth extraction and ASP procedure by means of demineralized bovine bone mineral particles covered with a porcine-derived non-cross-linked collagen matrix (CM). Each patient received a submerged single implant in the healed site. Mesial and distal peri-implant marginal bone resorption (MBR) rates were assessed radiographically at 1 year (T 1) and 5 years (T 2) after implant placement (baseline value). RESULTS AND STATISTICS: No dropouts occurred up to 5 years. At T 1, the MBR was 0.08 ± 0.16 mm at the mesial aspect and 0.1 ± 0.12 mm at the distal aspect. This difference was not statistically significant (P = 0.867). At T 2, the mesial MBR was 0.15 ± 0.17 mm and the distal MBR was 0.11 ± 0.14 mm, with a non-statistically significant difference (P = 0.532). Therefore, no statistically significant differences were detected comparing mesial and distal MBR at any time point. With respect to the intra-group comparisons, no differences were observed comparing the different study periods within each variable. Indeed, the comparison between T 0, T 1 and T 2 was non-statistically significant at both mesial (P = 0.06) and distal (P = 0.06) aspects. After 5 years, the volume of the soft tissues appeared clinically well maintained with a natural aspect around dental implants and adjacent teeth. CONCLUSION: ASP using demineralized bovine bone mineral in combination with CM proved to be an effective technique to maintain stable dimensional volumes of both hard and soft tissues.

Healing of Post-Extraction Sockets Filled with Anorganic Bovine Bone and Covered with a Xenogeneic Collagen Matrix. Radiological 2D and 3D Results of a Pilot Study to Assess Dimensional Stability.

Analysis of short-term results regarding dimensional stability of post-extraction sockets managed via a preservation protocol using deproteinized bovine bone matrix and a xenogeneic collagen matrix. Materials and methods Fifteen patients needing extraction of one single-rooted premolar tooth were treated in a pilot study. Five patients were treated in each centre. After tooth extraction, sockets were filled with anorganic bovine bone matrix and covered with a xenogeneic collagen matrix. Six months later, implants were placed. Dimensional changes in the treated sites were digitally evaluated using the best-fit superimposition of pre-and post-socket preservation models. Results After six months of healing, the vertical reduction of the grafted sites was 0.31 ± 0.24 mm (p < 0.001). Volumetric analysis of superimposed models showed an average palatal-lingual contraction of 0.33 ± 0.51 mm3 (p = 0.02). At the vestibular level, the average contraction was found to be 0.8 ± 0.3 mm3 (p < 0.001). Finally, the analysis of linear variations in the treated sites on a single sagittal section at the crystal level, and at 3 and 7 mm apically respect to the crest, both towards the vestibule and palate, generally showed more marked resorption at the crestal level compared to apical measurements. Conclusion: The clinical protocol herein employed for socket preservation showed a positive effect in preventing the physiological post-extraction remodeling.

Late Maxillary Sinus Graft Infections Due to Peri-implantitis: Case Reports with Histologic Analysis.

Maxillary sinus grafting is generally a safe procedure. However, intraoperative complications, as well as early and late postoperative complications, may occur. Included in the latter group are graft infections that can be triggered by peri-implantitis. The aim of the present study was to report three cases of late maxillary sinus graft infections and to histologically evaluate the effects of peri-implantitis in the grafted area. In peri-implantitis cases in grafted sinuses, the sole removal of the implant along with accompanying debridement of the infected area may not be sufficient to resolve the infection, and a more-aggressive treatment may be necessary.

Atrophic jaw reconstruction by means of calvarial bone graft: long-term results.

The aim of this work was to investigate the immunohistochemical and histologic patterns occurring in samples obtained from sites reconstructed with calvarial bone graft, 4 months (T1) and 10 years (T2) after grafting, in comparison to those observed in samples from the calvaria taken from the donor sites at the moment of withdrawal for the grafting (T0).Samples underwent immunohistochemical analysis for bone sialoprotein, matrix metalloproteinases 2 and 9, vascular endothelial growth factor, and Bax expressions; terminal-deoxynucleotidyl-transferase-mediated dUTP nick end-labeling analysis to evaluate the number of apoptotic samples; and morphologic evaluation after hematoxylin and eosin staining.The expression levels of all the investigated molecules, such as the apoptotic cells' count, showed a significant (P < 0.05) increase in T1 samples, that is, 4 months after grafting, although their expression levels recorded after 10 years seemed to be comparable to those in the native bone. Moreover, at observation under the light microscope, T1 samples showed a nonuniform morphology, with mineralized areas surrounded by connective tissues where blood vessels could be distinguished. On the other hand, T0 and T2 samples showed a similar aspect, characterized by uniform areas of mineralized extracellular matrix with cavities containing osteocytes.These data suggest that, after approximately 4 months, it is possible to highlight stronger remodeling phenomena, accompanied by new bone formation and new blood vessel proliferation, which are necessary to the host tissue for graft integration. On the contrary, these phenomena could not be observed in samples obtained after a long period (T2), which reveal a morphologic and an immunohistochemical pattern comparable to that recorded in calvarial native bone (T0).

Influence of novel nano-titanium implant surface on human osteoblast behavior and growth.

PURPOSE: The aim of the study is to investigate human osteoblast-like cell behavior and growth in the presence of 3 different titanium implant surfaces. MATERIALS: Human stem cells were first obtained and then sorted by fluorescence-activated cell sorter from mesenchymal stem cell clusters of human dental papilla. The obtained human dental papilla stem cells were induced to differentiate into osteoblast-like cells and were then analyzed by reverse transcriptase polymerase chain reaction and Western blot analyses. The cells proliferated and were cultured onto 3 different titanium discs (sandblasted, sandblasted and large-grit acid-etched, and full contact coverage [FCC]) and analyzed by scanning electron microscope. RESULTS: In all analyses samples, a high cell activity was observed, with typical osteoblast mature morphostructural response on rough surface. The high number of osteoblast-like cells was found on titanium FCC discs. At the same time, scanning electron microscope analysis confirmed the high biocompatibility of this surface. CONCLUSION: The rapid maturation of the osteoblast-like cells on FCC titanium surface suggests that this structure could play a central role during initial phases of bone healing processes.

Virtual Implant Rehabilitation of the Severely Atrophic Maxilla: A Radiographic Study.

BACKGROUND: Advanced maxillary atrophy is one of the most common clinical scenarios where implant placement could become difficult. Nevertheless, a volumetric evaluation using a suitable diagnostic software could facilitate the implant planning. The purpose of the present study is to suggest the potential application of the maxillary retro-canine area as the designated location for virtual tilted implants. METHODS: A sample of Cone Beam Computed Tomography (CBCT) images from the Department of Dentistry (IRCSS San Raffaele, Milan, Italy) was evaluated. After a 3D anatomical evaluation, tilted implants were virtually positioned in the retro-canine regions. All the implants were inserted using the same procedure at 30° and 45° degrees of tilting. The length, palatal angulation and diameter of the placed implant were identified. RESULTS: A total of 220 tilted implants were placed. An average implant measurement of 13.51 mm in length and 3.42 mm in diameter were calculated. Additionally, an average buccal-palatal angulation of 6° was identified. Upon statistical analysis, the implant length was found to be significantly higher at 45° degrees of mesio-distal angulation than at 30° degrees (<0.0001). CONCLUSIONS: A considerable number of patients show a significant degree of bone atrophy. The implant-supported treatment plan can rely on three-dimensional imaging of the residual bone as a guiding tool to establish the most effective implant position for each specific case. In this study, it was found that an implant could have a greater length if its mesio-distal angulation was more accentuated. In addition, owing to the volumetric evaluation, it was possible to virtually insert tilted implants in almost all of the cases of atrophy. This could lead clinicians to consider the retro-canine area as a viable place to insert a longer tilted implant.

Evaluation of effects on bone tissue of different osteotomy techniques.

The aim of this study is to evaluate and compare the response of bone tissue after osteotomy carried out with either rotating cutters or with piezoelectric terminals.Bioptic samples of bone tissue were taken during operations with rotating burs and piezoelectric terminals to increase bone volume before implantology. Samples first underwent histomorphometric analysis. Subsequently, osteoblastic cells, obtained from different samples, were placed in culture and allowed to proliferate to in vitro evaluate the time to initiate growth and to reach confluence. Finally, a molecular biologic study by reverse transcription polymerase chain reaction was performed to evaluate the expression of typical osteoblastic molecular markers, such as osteoprotegerin and osteopontin.Histomorphometric analysis showed that the width of necrotic line on the osteotomic margins from samples taken using different techniques did not vary significantly. Moreover, the times of initial growth and of confluence in cells from the 2 groups did not show any statistically significant differences. However, a highly significant correlation was revealed between the age of the patient and the initial growth time and the confluence. Similarly, reverse transcription polymerase chain reaction showed that the osteoprotegerin and osteopontin expression levels did not change significantly according to the surgical technique used.In conclusion, osteotomies carried out with either instrument do not seem to substantially influence the vitality of the bone tissue. The variability of the expression levels of typical osteoblastic markers seems to be linked more to other factors than to the surgical technique used.