Magnesium-enriched Hydroxyapatite Research Articles

Potentiality of chitosan hybridized magnesium doped-hydroxyapatite (CH/Mg·HAP) for enhanced carrying of oxaliplatin: loading, release, kinetics, and cytotoxicity

Magnesium-enriched hydroxyapatite was synthesized and integrated with chitosan, forming a bio-compatible biocomposite (CH/Mg·HAP) to be applied as a carrier of oxaliplatin (OXN) with enhanced loading, release, and therapeutic activities.

Bone Assessment in Grafted and Ungrafted Sockets After Dental Implant Placement: A 10-year Follow-up Study.

The purpose of this study was to compare success and outcomes among implants positioned either in grafted or ungrafted alveoli during 10 years of follow-up. This retrospective analysis was conducted on data of subjects who underwent tooth extraction and alveolar ridge preservation. Sites, one per patient, were ranked into three groups: postextraction ungrafted alveoli, and postextraction grafted alveoli with either synthetic magnesium-enriched hydroxyapatite or porcine bone. An absorbable collagen sheet was used to completely cover all the sockets. A secondary intention healing was sought for all procedures. Data regarding implant survival and marginal bone loss around implants were gathered until the 10-year follow up. Pairwise comparisons were performed with nonparametric tests, and statistical significance was set at .01. Sixty-three subjects were included: 42 implants (19 and 23 in the magnesium-enriched hydroxyapatite and porcine bone groups, respectively) placed in grafted sites and 21 in nongrafted sites. The success rate of the grafted groups was 88.1% (CI: 78.3% to 97.9%) at the 10-year follow-up. On the other hand, in the ungrafted group, the overall success rate was 85.7% (CI: 70.8% to 100%). Peri-implant marginal bone loss at the 10-year follow-up for the magnesium-enriched hydroxyapatite group was 1.2 (0.7) mm, while for the porcine bone group, it was close to 0. The behavior of the ungrafted group appeared to be significantly different compared with both grafted groups; however, marginal bone levels ranging from 0.1 to 0.4 mm were observed from 3 to 10 years. A difference in terms of long-term success rates between grafted and ungrafted sites was not revealed. Bone loss was significantly higher in the magnesium-enriched hydroxyapatite grafted group compared with those in the other groups (without or with other bone substitute material).

Prospective Clinical and Histologic Evaluation of Alveolar Socket Healing Following Ridge Preservation Using a Combination of Hydroxyapatite and Collagen Biomimetic Xenograft Versus Demineralized Bovine Bone.

This prospective study is aimed at investigating clinically and histologically the effectiveness of a biomimetic magnesium-enriched-hydroxyapatite (MgHA)/collagen-based bone substitute for alveolar socket preservation. Patients scheduled for posterior single tooth extraction were included. The alveolar socket was filled either with MgHA or deproteinized bovine bone matrix (DBBM). In DBBM group, a punch of mucosa was taken from the palate and used to cover the graft. Vertical and horizontal dimensional changes of the alveolar process were assessed clinically with a periodontal probe and with 3-dimensional (3D) analysis of a cast model. Postoperative quality of life was assessed through a questionnaire. After 6 months of healing, an alveolar tissue biopsy was taken for histologic and histomorphometric analysis of the newly formed tissue. After checking normality of the distributions, parametric or nonparametric tests were used for statistical comparisons. Twenty patients (12 males, 8 females, mean age 42.8 ± 5.1 years, range 33-50 years) were treated. After 6 months, vertical and horizontal alveolar ridge resorption was similar in the 2 groups. The 3D analysis of the models showed a significantly higher resorption at the buccal side than at the palatal/lingual side. Histomorphometric analysis showed similar new bone formation for MgHA group (23.07 ± 10.3%) and DBBM (22.77 ± 6.95%), and a significantly higher residual material% for DBBM (15.77 ± 1.95%) than MgHA (5.01 ± 1.04%). Significantly less pain was reported in the first 3 days after surgery in patients of the MgHA group. The MgHA was as safe and effective as DBBM and may represent a feasible bone substitute for alveolar socket preservation.

Alveolar Ridge Preservation after Tooth Extraction Using Different Bone Graft Materials and Autologous Platelet Concentrates: a Systematic Review.

ABSTRACTObjectivesTo review and assess the efficiency of different post extraction socket preservation techniques.Material and MethodsAn electronic literature search was performed on the MEDLINE and Embase databases. The review included human studies published between from January 1st, 2007 to January 1st, 2018, in English. Outcome measures included dimensional changes and/or histological evaluation of alveolar bone.ResultsTwenty-six full text articles were reviewed, 16 of which met the inclusion criteria and were selected for the study. Autogenous tooth graft prevented vertical resorption the most: -0.28 (SD 0.13) mm, observation period (OP): 4 months, while the least effective approach was beta tri-calcium phosphate (β-TCP): -1.72 (SD 0.56) mm, OP: 4 months. Estimating horizontal resorption, the most effective technique was biphasic calcium sulphate (BCS) with β-TCP and hydroxyapatite (HA) - BCS + TCP + HA: 0.03 (SD 2.32) mm, OP: 4 months, while β-TCP was the least efficient: -1.45 (SD 0.4) mm, OP: 4 months. Evaluating residual graft particles (RG) and newly formed bone (NFB) ratio the best results were achieved with demineralized freeze-dried bone allograft: RG: 8.88%, NFB: 38.42%, OP: 5 months, whereas magnesium-enriched hydroxyapatite was least effective: RG: 40.82%, NFB: 31.85%, OP: 4 months.ConclusionsThis review revealed that even though there are numerous types of biomaterials for socket preservation none of them can completely stop alveolar bone loss after tooth extraction. Furthermore, lack of information about qualitative evaluation of bone was noticed indicating that further studies regarding this topic are needed.

Use of a Biomimetic Scaffold for the Treatment of Osteochondral Lesions in Early Osteoarthritis.

The aim of this study is to investigate clinical and radiographic outcomes of a biomimetic scaffold for the treatment of osteochondral knee lesions in patients with early OA. Study population was represented by 26 patients with a mean age of 44 years affected by early OA. Inclusion criteria were two episodes of knee pain for more than 10 days in the last year, Kellgren-Lawrence OA grade 0 or I or II, and arthroscopic findings of cartilage defects. Nineteen patients had a previous surgery, 11 of which were revision surgeries of osteochondral unit. All patients were treated with a biomimetic scaffold with a tri-layered structure of type I equine collagen and magnesium-enriched hydroxyapatite. Clinical outcomes were evaluated using the IKDC, Lysholm, VAS, KOOS, and Tegner scores at baseline and at an average follow-up of 35 months. Magnetic resonance imaging (MRI) was performed at follow-up time in 19 patients. Clinical outcomes showed significant improvement in VAS, Lysholm, IKDC subjective score, and KOOS subscales in 69% of the patients. Complication rate of this cases series was 11%, with no surgical failure, although 31% of patients did not reach a significant improvement and were thus considered as clinical failure. MRI analysis showed integration of the scaffold only in 47% of the patients, with partial regeneration of the subchondral bone. No correlation between clinics and radiological images was found. The use of a biomimetic osteochondral scaffold in the setting of an early OA, alone or associated with other procedures, appeared to be a valid and safe option, able to provide good and stable clinical outcomes with high patient's satisfaction and low complication rate.

Histomorphometric Results After Postextraction Socket Healing with Different Biomaterials: A Systematic Review of the Literature and Meta-Analysis.

The aim of this systematic review was to investigate which material is the most effective bone substitute for alveolar bone healing by evaluating histomorphometric outcomes after healing of postextraction sockets in humans. A manual and electronic search (PubMed, EMBASE, Cochrane Library) was performed using a search string prepared ad hoc. Data were statistically analyzed by calculating weighted mean percentage of new bone formation (primary outcome) and weighted mean percentage of residual biomaterial, soft/connective tissue, and nonmineralized tissue (secondary outcomes) in the biopsies. A meta-analysis of the included randomized controlled trials (RCTs) was performed. A total of 802 papers were screened. After application of the inclusion and exclusion criteria, a total of 40 articles were included in the quantitative synthesis while 11 were included in the meta-analysis of comparative studies. The evaluation of comparative studies with empty sites as control showed that bovine bone could lead to a lower proportion of new bone formation compared to sites left to heal spontaneously (P < .00001). Magnesium-enriched hydroxyapatite and porcine bone showed a significantly higher percentage of new bone compared to control sites (P < .00001). Grafting with an allograft did not lead to a higher percentage of new bone formation in comparison with control sites (P = .09). There was no evidence for the superiority of a given biomaterial over the others in terms of new bone formation. While calcium sulphate and beta-tricalcium phosphate resorbed faster than other biomaterials, xenografts showed a lower resorption rate than allografts. Comparative studies suggested that bovine bone was related to a lower proportion of new bone volume compared to sites left to heal spontaneously, while porcine bone and magnesium-enriched hydroxyapatite were related to higher new bone volume. Allograft was not related to higher new bone volume than sites healed without any biomaterial.

Bone augmentation after ectopic implantation of a cell-free collagen-hydroxyapatite scaffold in the mouse.

The bone grafting is the classical way to treat large bone defects. Among the available techniques, autologous bone grafting is still the most used but, however, it can cause complications such as infection and donor site morbidity. Alternative and innovative methods rely on the development of biomaterials mimicking the structure and properties of natural bone. In this study, we characterized a cell-free scaffold, which was subcutaneously implanted in mice and then analyzed both in vivo and ex vivo after 1, 2, 4, 8 and 16 weeks, respectively. Two types of biomaterials, made of either collagen alone or collagen plus magnesium-enriched hydroxyapatite have been used. The results indicate that bone augmentation and angiogenesis could spontaneously occur into the biomaterial, probably by the recruitment of host cells, and that the composition of the scaffolds is crucial. In particular, the biomaterial more closely mimicking the native bone drives the process of bone augmentation more efficiently. Gene expression analysis and immunohistochemistry demonstrate the expression of typical markers of osteogenesis by the host cells populating the scaffold. Our data suggest that this biomaterial could represent a promising tool for the reconstruction of large bone defects, without using exogenous living cells or growth factors.

Alveolar socket preservation technique: Effect of biomaterial on bone regenerative pattern

BackgroundThere is a lack of evidence in the literature on the correlation between histomorphometric findings and gene/protein expression markers for bone metabolism. AimEvaluation of the histological features, changes in protein expression and gene activation for specific markers of bone metabolism following application of the alveolar ridge preservation technique with magnesium-enriched hydroxyapatite (MgHA). Materials and methodsFor each patient (n=15), bone samples were harvested after tooth extraction and processed for immunohistochemical and gene expression analysis (T0). Then, all alveolar sockets were grafted with MgHA. After 4 months (T1), bone samples were harvested for histomorphometrical, immunohistochemical and gene expression analysis. Gene expression and protein expression were evaluated for: RANK, RANKL, OPG, IL-6, TNF-α. ResultsFor all markers, gene expression increased, but not significantly, from T0 to T1. The mean RANKL/OPG ratio was 1.88±1.24. Protein expression increased significantly (p<0.05) for TNF-α, IL-6, RANK and RANKL. Histomorphometrical features at T1 were not significantly related to protein expression at T0. ConclusionsAfter ridge preservation with MgHA, markers for bone catabolism were activated. No significant correlation was found between histomorphometrical features of the regenerated tissue and protein expression at baseline.

Immunohistochemical and molecular analysis of bone remodelling pattern in alveolar socket

Following tooth extraction, the alveolar bone remodelling process starts. Bundle bone and buccal wall resorption occur early with horizontal and vertical bone crest reduction [1]. The use of bone substitutes has been proposed to limit bone resorption, thus allowing further dental rehabilitation [2]. Aim of this project was to characterize by a molecular and morphological approach the physiological remodelling of post-extractive alveolar socket and to compare it with the bone remodelling occurring after alveolar bone reconstruction with an alloplastic material. Thirty-six patients needing tooth extraction were enrolled and equally divided into three groups: A) baseline, B) spontaneous healing, C) biomaterial. In each group, 2 biopsies per site were harvested during tooth extraction (group A) or 4-6 months after tooth extraction (groups B and C). In group B, patients recovered spontaneously, while in group C the alveolar socket was filled with a magnesium-enriched hydroxyapatite. One biopsy was processed for immunohistochemistry to localise TNF-α, IL-6, RANK, RANKL and OPG. The second biopsy underwent a Real-Time PCR analysis for the same biomarkers in order to evaluate gene expression. In groups B and C, a third biopsy was retrieved and processed for ground section aiming to assess tissue composition. Differences between the three groups were investigated using Kruskal Wallis test (p<0,05) followed by post-hoc tests. All samples showed a normal structure without inflammatory infiltrate. At immunohistochemical analysis, all biomarkers except for OPG had increased. Significant differences were found between the three groups for TNF-α (p< 0,05), IL-6 (p<0,001), RANK (p< 0,01) and RANKL (p<0,001), between groups A and C for IL-6 (p≤ 0,001), RANK (p≤ 0,01), RANKL (p≤ 0,001) and between B and C for IL-6 (p≤ 0,01). Gene expression did not show statistical differences. Crumbles of biomaterial surrounded by regenerated bone were evident. A higher percentage of mineral component was obtained in group B than in C. The biomarkers selected in the current study were involved in the alveolar remodelling and the biomaterial used for socket preservation did not influence the process.

Permanent mucosal discoloration correlated to magnesium-enriched hydroxyapatite: A case report

Permanent mucosal discoloration correlated to magnesium-enriched hydroxyapatite: A case report

Guided Bone Regeneration for Socket Preservation in Molar Extraction Sites: Histomorphometric and 3D Computerized Tomography Analysis

Guided Bone Regeneration for Socket Preservation in Molar Extraction Sites: Histomorphometric and 3D Computerized Tomography Analysis

Role of amniotic fluid mesenchymal cells engineered on MgHA/collagen-based scaffold allotransplanted on an experimental animal study of sinus augmentation

The present research has been performed to evaluate whether a commercial magnesium-enriched hydroxyapatite (MgHA)/collagen-based scaffold engineered with ovine amniotic fluid mesenchymal cells (oAFMC) could improve bone regeneration process in vivo. Bilateral sinus augmentation was performed on eight adult sheep in order to compare the tissue regeneration process at 45 and 90 days after implantation of the oAFMC-engineered scaffold (Test Group) or of the scaffold alone (Ctr Group). The process of tissue remodeling was analyzed through histological, immunohistochemical, and morphometric analyses by calculating the proliferation index (PI) of oAFMC loaded on the scaffold, the total vascular area (VA), and vascular endothelial growth factor (VEGF) expression levels within the grafted area. MgHA/collagen-based scaffold showed high biocompatibility preserving the survival of oAFMC for 90 days in grafted sinuses. The use of oAFMC increased bone deposition and stimulated a more rapid angiogenic reaction, thus probably supporting the higher cell PI recorded in cell-treated sinuses. A significantly higher VEGF expression (Test vs. Ctr Group; p = 0.0004) and a larger total VA (p = 0.0006) were detected in the Test Group at 45 days after surgery. The PI was significantly higher (p = 0.027) at 45 days and became significantly lower at 90 days (p = 0.0007) in the Test Group sinuses, while the PI recorded in the Ctr Group continued to increase resulting to a significantly higher PI at day 90 (CTR day 45 vs. CTR day 90; p = 0.022). The osteoinductive effect of a biomimetic commercial scaffold may be significantly improved by the presence of oAFMC. The amniotic fluid mesenchymal cell (AFMC) may represent a novel, largely and easily accessible source of mesenchymal stem cells to develop cell-based therapy for maxillofacial surgery.

Ridge preservation after tooth extraction

Following tooth extraction, the alveolar ridge will undergo dimensional changes. This change may complicate the subsequent restorative procedure when oral implants are chosen. "Alveolar ridge preservation" has been assessed in various studies. To evaluate the more recent studies on this topic and to explore new insights under this topic. Animal studies and clinical studies have addressed different techniques. Implants placed into the fresh extraction sockets do not prevent the resorption of the alveolar bone. Simultaneous guided bone regeneration could partially resolve alveolar bone resorption. The use of root-formed implants does not preserve alveolar ridges. Moreover, various bone substitutes have been tested: magnesium-enriched hydroxyapatite, human demineralized bone matrix, and deproteinized bovine bone mineral have been shown to be effective in ridge preservation. Applying the guided bone regeneration principle using bone substitutes together with a collagen membrane has shown clear effects on preserving alveolar ridge height as well as ridge width. Soft tissue grafts or primary closure did not show beneficial effect on preserving the alveolar bone.

Histological evaluation at different times after augmentation of extraction sites grafted with a magnesium‐enriched hydroxyapatite: double‐blinded randomized controlled trial

To histologically analyze the early angiogenesis-osteogenesis interplay in post-extraction sockets augmented with magnesium-enriched hydroxyapatite (Mg-enriched HA). Ten post-extraction sites underwent post-extraction ridge preservation procedure. According to randomization, sites were divided into two balanced groups and bone specimens were collected 2 or 4months after surgery. Sections were stained with hematoxylin/eosin, Masson-Goldner trichrome, and tartrate-resistant acid phosphatase (TRAP), respectively. Furthermore, indirect immunohistochemistry was performed using alkaline phosphatase, CD34 and caveolin-1 antibodies. Mean values and standard deviations were calculated for each outcome variable. Data were then compared using one-way ANOVA test. P<0.05 was considered statistically significant. Histomorphometric analysis presented 15.0% (±3.5) regenerated bone after 2months of healing. After 4months, regenerated bone increased 5.1-fold up to 77.4% (± 8.6) (P<0.001). On the contrary, vessels and capillary reduced from 645 (±33) to 255 (± 94) (caveolin-1 expression, P=0.008). These findings were confirmed by CD34 expression (301±95 and 88 (±24), respectively, at 2 and 4months (P=0.046). Within the limits of the present randomized controlled study, it can be concluded that Mg-enriched HA is a suitable material for socket preservation and ensures early angiogenesis and early osteogenesis.

Crestal minimally-invasive sinus lift on severely resorbed maxillary crest: prospective study

This case series aimed to explore the clinical outcome of sinus floor elevation surgery using a crestal approach technique in case of severely resorbed maxillae. Seventeen edentulous patients received 20 implants and sinus floor elevation in posterior maxillae with residual crestal height of 1.2-5.0 mm and >7 mm. Drilling perforation was performed until the sinus floor was felt; the sinus mucosa was then lifted and magnesium-enriched hydroxyapatite granules (Mg-e HAP) were placed; and implants were immediately inserted. Four months later, definitive crowns were cemented, and patients were followed up for 24 months. Implant failures and complications 24 months after prosthetic loading were noted, and radiographic regenerated bone height was measured. No patient dropped out, and all implants were successfully osseointegrated. There was minimal postoperative patient discomfort, and the only complication was a minimal perforation of the sinus membrane with no negative consequences. At the time of implant insertion, the residual crestal height mean value was 4.12 mm. After surgery and at the last follow-up, the mean heights of bone were 13.51 and 12.98 mm, respectively. The procedure was able to obtain sinus elevation and implant osseointegration.

Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs

To evaluate the influence of magnesium-enriched hydroxyapatite (MHA) (SintLife(®)) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets. In the mandibular pre-molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. After 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone-to-implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance. The use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest.

Osteotome Sinus Floor Elevation and Simultaneous Implant Placement in Grafted Biomaterial Sockets: 3 Years of Follow‐Up

Immediate bone grafting procedures were proposed to preserve bone volume in residual damaged alveolar walls and to prevent the expansion of the sinus floor in the maxillary molar region. The use of an osteotome allows vertical bone augmentation and localized sinus elevation with minimal surgical trauma. The aim of this study is to evaluate the clinical outcome of implants placed in previously grafted alveoli that were expanded at a second-stage surgery by an osteotome technique. Twenty patients requiring extraction of one or two upper molar teeth and/or a second premolar were selected. Thirty teeth were extracted, and their fresh sockets immediately received magnesium-enriched hydroxyapatite as a graft material. Three months after bone filling, osteotome sinus floor elevations were performed in grafted sites, and 30 titanium dental implants were placed. Three months after implant placement, temporary restorations were performed. Follow-up examinations and intraoral digital radiographs were taken at baseline and 6, 12, 24, and 36 months after implant placement to evaluate the alveolar bone gain for each implant. Comparisons among mean values of alveolar bone gain over time were performed by the Student two-tailed t test. At the 36-month follow-up, a survival rate of 100% was reported for all implants. The alveolar bone gain after 6 months of healing was 2.41 +/- 1.23 mm. Successively, after 12 months, the bone gain increased (3.85 +/- 1.37 mm). At 24 and 36 months after implant placement, the levels were stable (3.86 +/- 1.50 mm and 3.82 +/- 1.57 mm, respectively). Statistical analyses showed a significant difference (P <0.05) only between the 6- and 12-month values. At the 36-month follow-up, the use of the osteotome technique for vertical expansion of the grafted tissue was considered a predictable procedure in the implant surgery.

Dental Implants Placed in Extraction Sites Grafted With Different Bone Substitutes: Radiographic Evaluation at 24 Months

Reduction of alveolar height and width after tooth extraction may provide some problems in implant placement, especially in the anterior maxilla for esthetic reasons. Different graft materials have been advocated to prevent bone-volume reduction. The aim of this study was to evaluate radiographic parameters of implants positioned in grafted alveoli with three different biomaterials: magnesium-enriched hydroxyapatite (MHA), calcium sulfate (CS), and heterologous porcine bone (PB). In 15 patients, 45 fresh extraction sockets with three bone walls were selected. Fifteen sockets received MHA, 15 sockets received CS, and 15 sockets received corticocancellous PB as a graft material. Three months after bone filling, titanium dental implants were placed in grafted sites. Three months after implant placement, temporary restoration was performed. Follow-up examinations were conducted, and intraoral digital radiographs were taken at baseline and 12 and 24 months after implant placement to evaluate the marginal bone level in each patient. Comparisons for marginal bone loss over time between groups were performed by the Student two-tailed t test. At the 24-month follow-up, a survival rate of 100% was reported for all implants. For the MHA group, a mean mesial bone loss of -0.21 +/- 0.08 mm and a mean distal bone loss of -0.22 +/- 0.09 mm (mean bone loss: 0.21 +/- 0.09 mm) were reported; for the CS group, a mesial bone loss of -0.14 +/- 0.07 mm and a distal bone loss of -0.12 +/- 0.11 mm (mean bone loss: -0.13 +/- 0.09 mm) were measured; for the PB group, a mean mesial bone loss of -0.15 +/- 0.10 mm and a mean distal bone loss of -0.16 +/- 0.06 mm (mean bone loss: -0.16 +/- 0.08 mm) were reported. No statistically significant differences were reported among groups (P >0.05). At the 24-month follow-up, the present study showed that placement of implants in grafted sockets was not influenced by the three different biomaterials because they did not negatively impact the clinical outcome.

Magnesium‐Enriched Hydroxyapatite Versus Autologous Bone in Maxillary Sinus Grafting: Combining Histomorphometry With Osteoblast Gene Expression Profiles Ex Vivo

Many biomaterials are proposed for sinus floor lifting and grafting in the posterior maxilla for insufficient bone volume (BV). The aim of this study was to compare the use of magnesium-enriched hydroxyapatite (mHA) versus autogenous bone graft (AB) for maxillary sinus lift procedures by histomorphometric and ex vivo gene expression profiling. Fifteen patients requiring bilateral maxillary sinus augmentation received autologous bone particles (group A) and mHA (group B) (split-mouth design). Five months later, implants were placed, and biopsies were obtained. Bone specimens were analyzed by histomorphometry, BV and vital bone (VB) percentages were calculated, and ex vivo osteoblast expansion followed by highly sensitive osteoblast specific gene expression profiling for cbfa1, osteocalcin, osteopontin, collagen type I, receptor activator of nuclear factor-kappa B ligand (RANKL), and osteoprotegerin (OPG) by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) were performed. Comparisons were made using the Student t test. After healing with no complications, BV was comparable in the two groups (80.79% +/- 14.27% for autologous versus 76.72% +/- 11.47% for mHA; P = not statistically significant), but VB was lower in the mHA group (29.65% +/- 9.81% versus 78.40% +/- 16.72%; P <0.05). Real-time RT-PCR analyses showed significantly higher expression of the osteoblast differentiation factor Cbfa1 and the matrix formation marker osteocalcin in the mHA group compared to the AB group, whereas type I collagen was comparable, and osteopontin was decreased. Attesting to a lower osteoclastogenic potential, the RANKL/OPG ratio was diminished. Autogenous bone samples provided higher vital over comparable total bone levels than mHA-grafted sites. Osteoblast gene expression profiles from mHA grafts revealed higher expression of certain specific markers of osteoblast differentiation and bone formation, associated with a lower osteoclastogenic potential.

Magnesium‐Enriched Hydroxyapatite Compared to Calcium Sulfate in the Healing of Human Extraction Sockets: Radiographic and Histomorphometric Evaluation at 3 Months

Reduction of alveolar height and width after tooth extraction may present problems for implant placement, especially in the anterior maxilla where bone volume is important for biologic and esthetic reasons. Different graft materials have been proposed to minimize the reduction in ridge volume. The aim of this study was to compare radiographic and histomorphometric results of magnesium-enriched hydroxyapatite (MHA) and calcium sulfate (CS) grafts in fresh sockets after tooth extractions. Forty-five fresh extraction sockets with three bone walls were selected in 15 patients. A split-mouth design was used: 15 sockets on the right side of the jaw received MHA, 15 sockets on the left side received CS, and 15 random unfilled sockets were considered the control (C) group. Intraoral digital radiographs were taken at baseline and at 3 months after graft material placement. At 3 months, cylinder bone samples were obtained for histology and histomorphometry analysis. The difference in mean radiographic vertical bone level from baseline to 3 months was -2.48 +/- 0.65 mm in the CS group, -0.48 +/- 0.21 mm in the MHA group, and -3.75 +/- 0.63 mm in the unfilled C group. Statistically significant differences (P <0.05) were found between CS and MHA groups and between MHA and C groups. Histologic examination revealed bone formation in all treated sites; trabecular bone assessment did not differ among apical, mesial, and coronal portions of the specimens. Mean vital bone measurements for CS, MHA, and C groups were 45.0% +/- 6.5%, 40.0% +/- 2.7%, and 32.8% +/- 5.8%, respectively. Statistically significant differences (P <0.05) were found among all groups. Connective tissue percentages averaged 41.5% +/- 6.7% for the CS group, 41.3% +/- 1.3% for the MHA group, and 64.6% +/- 6.8% for the C group. Statistically significant differences (P <0.05) were found between CS and C groups and between MHA and C groups. The CS-grafted sockets showed 13.9% +/- 3.4% residual implant material, whereas the MHA-treated sockets showed 20.2% +/- 3.2% residual material. The difference between the groups was statistically significant (P <0.05). Radiographs revealed a greater reduction of alveolar ridge in the CS group than in the MHA group. Histologic examination showed more bone formation and faster resorption in the CS group and more residual implant material in the MHA group.