Carolina Sbordone

Volume changes of autogenous bone grafts after alveolar ridge augmentation of atrophic maxillae and mandibles

The aim of the present retrospective chart review was to determine the relationship between nonvascularized osseous graft remodeling and the three-dimensional (3D) features of grafts and recipient sites, the anatomical recipient regions and different graft sources. 32 iliac crest or chin grafts were onlay-positioned in the mandible or maxilla of 14 patients. CT scans, taken before implant positioning and after 1 year, revealed a mean volume resorption of 35-51%. For iliac crest grafts, the average resorption was 42% when the onlay was positioned in the anterior maxilla and 59% when it was positioned in the posterior mandible. Spearman correlation and 3D interpolation analysis revealed, for both iliac crest groups, a moderate or advanced remodeling pattern depending on 3D features, namely graft thickness and shape, basal bone volume of recipient site, and the basal bone/graft volume ratio of the recipient site. No statistically significant differences were found between the recipient and donor site groups. Retrospective analysis of the data indicates that iliac crest grafts, onlay-positioned on adequate basal bone volume, may register a reduced volume remodeling when shaped thick in the anterior maxilla or rounded and convex, on the external surface, in the posterior mandible.

Volume changes of autogenous bone after sinus lifting and grafting procedures: A 6-year computerized tomographic follow-up

OBJECTIVES To evaluate long-term bone remodelling of autografts over time (annually, for 6 years), comparing the block and particulate bone procedures for sinus floor elevation, as well as to evaluate the survival of positioned dental implants. PATIENTS AND METHODS Twenty-three sinus lift procedures with autogenous bone were performed: seven sinus lift procedures using particulate graft and 10 with block autogenous bone were performed in 17 patients. Employing a software program, pre- and post-surgical computerized tomography (CT) scans were used to compare the volume (V) and density (D) of inlay grafts over time (up to 6 years), and to determine the percentage of remaining bone (%R). All variable (V, D and %R) measurements were then compared statistically. RESULTS At the 6-year survey for block form, a resorption of 21.5% was seen, whereas for particulate grafts there was a resorption of 39.2%. Both groups exhibited bone remodelling between the first and second follow-up which was significant regarding volume for the block form and regarding density for the particulate group. CONCLUSIONS During the initial period of healing, the cortico-cancellous block bone grafted into the maxillary sinus underwent a negative remodelling of the volume, which is most probably due to graft cortex resorption, coupled with, primarily, an increase in density in the spongious area; for the particulate grafts, significant augmentations in density were obtained. The lack of significant differences among volumes was due to the wide degree of dispersion of the data. The rough data presented in this paper seem to support the use of a bone-block grafting procedure in maxillary sinus augmentation.

Apical and marginal bone alterations around implants in maxillary sinus augmentation grafted with autogenous bone or bovine bone material and simultaneous or delayed dental implant positioning

OBJECTIVE A re-pneumatization phenomenon was recorded in sinuses grafted with different materials. The specific aims of this paper were to assess the dental implant survival rate and the behavior of marginal and apical bone remodeling around dental implants placed following sinus augmentation. MATERIALS AND METHODS A retrospective study was conducted on consecutive patients treated in two surgical centers. Different surgical techniques were adopted for sinus augmentation: simultaneous or delayed dental implant insertion with bovine bone-material augmentation or autologous bone grafting (chin and iliac crest). Survival rates were recorded for the overall number of implants (patients of group A). Apical and marginal bone levels (ABL and MBL, respectively) were radiographically measured, and statistical analysis was performed in implants of a subgroup of patients (group B). RESULTS A total of 282 dental implants were positioned. Recorded cumulative survival rates (CSRs) were 95.6% and 100% for autogenous and bovine bone material, respectively, while CSRs at 2-year follow-up for immediate and delayed procedures were 99.3% and 96.5%. For the subgroup B, 57 sinus augmentation procedures were performed in 39 patients, with the positioning of 154 implants. Generally, the apical- and marginal-bone resorption of the bovine bone-material group was less than that of the autogenous group. The differences between the ABL values of the bovine bone-material and iliac-crest groups were statistically significant at 1 year, whereas this significance disappeared at the 2-year follow-up; tests showed that a statistical difference was recorded in the bovine bone-material group between the 1- and 2-year follow-ups. With regard to MBL comparisons between simultaneous and delayed implantation, the differences maintained their significance at the 2-year follow-up also. CONCLUSIONS Differences regarding apical bone alteration between autogenous bone from the iliac crest and bovine bone material at the 1- and 2-year follow-ups, as well as in the bovine bone-material group between the 1- and 2-year follow-ups, attested to slower but more prolonged physiologic bone remodeling in the bovine-graft-material group than in the autogenous-bone group. The MBL analysis showed that remodeling in the delayed implant group demonstrated a greater resorption in the cervical portion than was seen in the simultaneous implant group.

Volume Changes of Iliac Crest Autogenous Bone Grafts After Vertical and Horizontal Alveolar Ridge Augmentation of Atrophic Maxillas and Mandibles: A 6-Year Computerized Tomographic Follow-Up

PURPOSE To evaluate by computerized tomography the long-term volume resorption of autogenous corticocancellous grafted bone harvested from the ilium and used in an alveolar augmentation procedure followed by endosseous dental implant placement. PATIENTS AND METHODS Eleven maxillary grafts (8 positioned horizontally) and 13 mandibular grafts (10 positioned vertically) were placed in 16 patients. Using software programs, pre- and postsurgical computerized tomographic scans were used to compare volumes of grafts over time (up to 6 yr) to determine the annual percentage of remaining bone and the overall percentage of bone resorption that could be expected. Yearly measurements of volumes and percentages of remaining bone were then compared statistically. RESULTS At the 6-year survey for blocks grafted in the mandible, an average resorption rate of 87% was obtained; for maxillary grafts at the same survey, complete resorption of the grafts (mean, 105.5%) was recorded. In general, bone resorption appeared slow, except for that recorded in the first 2 years of healing, the only period in which statistical comparisons among all time points showed significant differences for all variables. CONCLUSIONS Volumetric measurements of the grafts and their related percentages of remaining bone attested to a progressive and unavoidable bone resorption of almost all the grafted bone in the maxilla and mandible. Although the present data were from a heterogeneous group of defects treated with horizontal and vertical procedures, clinicians, when performing alveolar bone augmentation with an autogenous hip bone, should aim at titanium dental implant osseointegration, not only in the augmented bone but also in the native bone below the graft.

Volume Changes of Grafted Autogenous Bone in Sinus Augmentation Procedure

PURPOSE To evaluate associations between the osseous remodeling and the 3-dimensional features of both the grafted bone and the recipient site, as well as the density of the grafted bone, and to assess the relation between the degree of bone resorption and the type of autogenous bone-grafting procedure or the source (block or particulate bone from iliac crest or block bone from chin). PATIENTS AND METHODS A retrospective chart review of patients receiving sinus lifting and grafting procedures for implant positioning was conducted: radiographic analysis of the volume and area of both sinuses and autogenous bone grafts was performed, as per Smolka et al and Krennmair et al. The volumetric remodeling--measured at 1 year after implant positioning as the percentage of residual bone (%R)--was correlated, with Spearman analysis, to 3-dimensional features of both graft and recipient sites. All quantities correlated with %R at a statistically significant level were used for 2-dimensional and multidimensional visualizations with scattergrams. RESULTS Twenty-five iliac crest or chin grafts were inlay positioned in the maxillary sinuses of patients. Computed tomography scans, taken before implant positioning and after 1 year, showed a 1-year negligible volume remodeling for block graft from chin (97.9%) but slightly greater resorption values (%R) for particulate and block grafts from iliac crest (93.8% and 83.3%, respectively). Three- and four-dimensional scattergrams of significant data resulting from Spearman correlation tests (particulate and block grafts both from iliac crest) showed a variation of the remodeling pattern dependent on 3-dimensional features, namely inlay graft thickness, surface area of the graft in contact with basal bone, volume of the recipient site, and surface area of the graft projecting into the sinus cavity. CONCLUSIONS Retrospective data analysis shows that iliac crest grafts positioned on a small basal bone volume (≤ 2.5 mL) may point to a very favorable remodeling of the volume when the particulate graft is molded to a thickness of less than 4 mm, with a reduced surface area protruding into the sinus (≤ 5 cm(2)). Bone blocks with a reduced contact surface and with basal bone (≤ 4 cm(2)) also display minimal resorption.

pEGFR-Tyr 845 expression as prognostic factors in oral squamous cell carcinoma: A tissue-microarray study with clinic-pathological correlations

The EGFR (epidermal growth factor receptor) a member of the family of transmembrane protein kinase receptors known as the erbB family shows a significant correlation with the presence of metastases and poorly differentiated oral cancer. Aim of the present work is to define the key-role of EGFR in oral cancer prognosis. We have analyzed the EGFR expression on 149 cases of oral squamous cell cancers (OSCC) and we have found that it was poorly expressed in normal oral epithelium, but its expression was significantly increased in OSCCs. Moreover, we have recorded that both pEGFR-Tyr 845 and pEGFR-Tyr 1068 were mainly distributed in high histological grading and in advanced stages. Western blotting has confirmed the total absence of EGFR phosphorylation in normal oral epithelium and the higher level of protein phosphorylation in representative cases of OSCCs. The EGF-R amplification was found by fluorescence in situ hybridization (FISH) in 14% of OSCC; interestingly, EGF-R amplification was mainly observed in OSCC with higher histological grading (G2 and G3) and advanced stage (pT4) sub-groups. Kaplan-Meyer survival analysis suggested that patients with positive pEGFR-Tyr 845 tumors had a worse prognosis and were bad responders to chemotherapy. These results confirm the central role of EGF-R activation status as a prognostic biomarker in OSCC.

Healing of donor defect after mandibular parasymphyseal block harvesting: a 6-year computerized tomographic follow-up.

OBJECTIVES A long-term survey on the healing potential of large-sized parasymphyseal osseous defects. PATIENTS AND METHODS Ten patients, subjected to 14 bilateral and 3 unilateral parasymphyseal bone harvesting for alveolar ridge augmentation, were selected for the retrospective chart review. CT scans were performed immediately before bone grafting, before implant insertion, and then once annually for 6 years, and the volumes of the bone defects at the buccal aspect in the healing process were measured using a software program. Volumes from the yearly measurements were then compared statistically. RESULTS Volumes of both the intrasurgical defects, 0.77 (0.20) cc and of those in the one-year group, 0.60 (0.26) cc were statistically different from volumes of all the other time intervals (from 24 to 72 months) with all p-values less than 0.002 and 0.004, respectively. The healing of osseous defects in the long-term radiographic survey (6 years) resulted in bony infill of 63%. CONCLUSION For parasymphyseal defects of 0.7 cc, a maximum possible healing of two-thirds can be expected; a re-harvesting procedure could be performed 24 months after early surgery, due to both the formation of a new buccal cortical plate and the achievement of a steady state of osseous remodelling.

Clinical survey of neurosensory side-effects of mandibular parasymphyseal bone harvesting.

The aim of the present survey was to assess neurosensory disturbances and/or tooth-pulp sensitivity losses after mandibular parasymphyseal bone-harvesting procedures. Twenty-eight harvesting areas in 16 patients were surveyed. Mucosal and skin sensitivity of the chin/lower lip, divided into four regions, were determined via Pointed-Blunt and Two-Point-Discrimination Tests. Pulp sensitivity of the mandibular teeth from the left second bicuspid to the right second bicuspid was tested by cold vitality preoperatively and 12 months postoperatively. Teeth were grouped according to sensitivity alterations and distance from the harvesting defects, as measured on CT scans, and statistically significant differences sought. At 12 months, 29% of preoperatively vital cuspids overlying the harvesting defects revealed pulp-sensitivity losses; no patient reported anaesthesia or analgesia; hypoaesthesia was present in 4% (8 sites; 2 patients), hypoalgesia was present in 3% (5 sites; 2 patients) and Two-Point-Discrimination Tests yielded pathologic responses in 5% of tested areas (10 sites; 4 patients). Teeth with and without pulp sensitivity changes were statistically indistinguishable regarding distances between root apices or mental foramen and the harvesting defect. The loss of pulp sensitivity in any tooth cannot be predicted simply on the basis of the distance between its apex and the harvesting osteotomy line.

Gene clustering analysis in human osseous remodeling

BACKGROUND Tentative bioinformatic predictions were performed to comprehend the complexity of the gene interaction networks of the T lymphocyte cell cycle and of human periodontitis. This study aims to identify and rank genes involved in osseous augmentation or bone remodeling to obtain groups with more numerous predicted associations called the leader gene clusters. METHODS An iterative search (consisting of a consecutive expansion-filtering loop) was performed for which only genes involved in a specific process were identified. For each gene, predicted associations with all other involved genes were obtained from a Web-available database (Search Tool for the Retrieval of Interacting Genes/Proteins) and the weighted number of links (WNL), given by the sum of only high-confidence predicted associations (results with a score > or =0.9), allowing gene ranking. Genes belonging to higher clustering classes were identified. RESULTS A total of 161 genes potentially involved in bone-volume augmentation and 128 genes connected with the bone-remodeling phenomenon were identified. For the bone-volume augmentation process, only one gene belonged to the leader gene group, whereas six other genes were classified as cluster B genes; for the bone-remodeling phenomenon, three leader genes were identified, whereas six other genes formed the cluster B group. No one gene belonged to leader gene clusters of both processes, whereas one gene of each higher cluster group belonged to the immediately lower cluster of the opposite process. Only three genes of the higher clusters were experimentally involved in both analyses. CONCLUSIONS A de novo identification was performed based on the data mining of leader genes involved in bone-volume augmentation or bone remodeling to acquire primeval information about their molecular basis and to plan future ad hoc targeted experiments. For several genes of the upper clusters, an active role in the bone processes was already known, but the present analysis suggested that they play a major role in the analyzed phenomena. The role of the transcription factors as leader genes and the numerous orphan genes (genes with WNL = 0) recovered probably attest to a lack of information regarding these processes, which could be further clarified through specific DNA microarray experiments.

Five-year outcome of bone remodelling around implants in the maxillary sinus: assessment of differences between implants placed in autogenous inlay bone blocks and in ungrafted maxilla.

The placement of implants in the posterior maxillary area is considered a reliable procedure, offering recognized rehabilitative advantages. The aim of this study was to evaluate the performance of dental implants placed in the sinus floor augmented with a block autograft by comparing the outcomes over 5 years with those of dental implants positioned in non-augmented bone. This retrospective cohort study included 16 patients who had undergone prosthetic rehabilitation supported by dental implants between 2000 and 2006. One implant per patient was included and assigned to one of two predictor groups: grafted versus ungrafted maxillary sinus. Changes in marginal bone level (MBL) and apical bone level (ABL) over time, at 1, 3, and 5 years, were the primary outcome variables. Appropriate pair-wise comparison tests were performed. No significant differences were seen with regard to ABLs and among times between the grafted group (nine implants) and the ungrafted group (seven implants). Significant marginal bone resorption was found over time, primarily at the buccal aspect, in both study groups. The bone surrounding the apex of dental implants appeared stable after sinus augmentation in the grafted area. The behaviour of the two groups with regard to loss of MBLs over time was very similar.