Amount Of Bone Research Articles

Bone Augmentation Techniques with Customized Titanium Meshes: A Systematic Review of Randomized Clinical Trials

Background: A correct tridimensional implant placement requires a sufficient amount of bone to completely satisfy the prosthetic reconstruction. Several techniques can be used to recreate the bone quantity. Among them, titanium meshes have shown great potential in space maintenance and fewer complications in case of exposure. Recently, 3D CAD, CAM technology, and specifically SLM have been used to produce customized meshes in titanium alloy. The aim Purpose of this systematic review is to evaluate new customized meshes compared to traditional ones in terms of new volume of generated bone and the incidence of complications. Materials and Methods: A MEDLINE/PubMed literature search was performed to find relevant randomized controlled clinical trials published in English up to and including December 2022. The Cochrane Database of Systematic Reviews and SCOPUS were also searched. The main keywords used in the search were: titanium meshe(s), customized titanium meshe(s), combined with AND/OR as Boolean operators, and bone augmentation with/and/or titanium mesh. Results: The electronic search identified 1002 papers in total, and after duplicate removal, 500 articles were screened. After a manual screening of the title and abstract, 488 studies were excluded, and 12 articles' full text of 12 articles was analyzed. Further analysis was performed to make sure that the articles matched the inclusion/exclusion criteria of the present review. Six additional articles were excluded in this phase. No meta-analysis was performed due to the heterogeneity of the data. Conclusion: By using traditional or customized devices with the newly generated bone volume allowed the implant placement in all cases. Complications were mainly reported as exposure during the healing phase, but the conclusions of whether customized or conventional systems perform one better than the other are still inconclusive.

Technical note: Application and potentiality of quantitative ultrasonometry for the evaluation of bone mineral density status.

The evaluation of bone mineral density (BMD) is an important task in paleopathology. Techniques commonly applied in bone quantity assessment, such as DXA or radiogrammetry (XR), suffer from several limitations when applied to skeletal remains. In recently published research, we developed a new methodology and new reference curves for the evaluation of BMD on human skeletal remains, applying for the first time Quantitative Ultrasonometry (QUS), a user-friendly, portable, and reliable clinical technique. This study aims to apply this new methodology to an archeological sample and to compare the results with those obtained through XR. We apply QUS and XR to a sample of 104 adults from Medieval Italian cemeteries. Fragility fractures were recorded. Descriptive statistics and comparisons between sexes, age-at-death cohorts, and individuals with and without fragility fractures were performed. Moreover, univariate and multivariate logistic regression models were used to define the parameters most predictive of fracture risk in past populations. The comparison between sexes showed no significant results concerning BMD parameters, whereas a decrease in BMD with increasing age is confirmed. The comparison between fracture and non-fracture individuals and the logit model demonstrated that QUS parameters, especially UBPI, are more reliable predictors of fracture risk in comparison to XR. Our results confirmed that QUS is a valuable technique that can be efficiently applied to archeological remains, also considering its portability. We also propose a modification of the previously published QUS standard curves, to easily assess osteopenia and osteoporosis in archeological material.

Relative comparison of chronic kidney disease-mineral and bone disorder rat models.

Objective: The aim of this study is to establish a suitable animal model of chronic kidney disease-mineral and bone disorder (CKD-MBD) by comparing CKD-MBD rat models induced by 5/6 Nx, AN, and UUO, accompanied by a low-calcium and high-phosphorus diet. Methods: Sprague‒Dawley rats were randomly divided into four groups: control group, 5/6 nephrectomy (5/6 Nx) group, Adriamycin nephropathy (AN) group, and unilateral ureteral obstruction (UUO) group. Serum biochemical indices were measured to evaluate renal function, mineral and bone metabolism, the severity of CKD-MBD, and the status of bone transformation. Hematoxylin-eosin staining (HE) and Masson's trichrome (Masson) staining were used for histopathological analysis of the kidney. Goldner's trichrome (Goldner) and tartrate-resistant acid phosphatase (TRAP) staining were utilized to observe bone mineralization and osteoclasts in the femur, respectively. Micro-CT images were applied to study the structure of the femur. The expression levels of osterix and cathepsin K in the femur were measured by immunohistochemistry (IHC) to confirm the status of bone transformation. Results: The levels of serum creatinine (Scr) and blood urea nitrogen (BUN) in the 5/6 Nx and AN group rats were significantly higher than those in the control rats, and this change was accompanied by marked changes in the levels of calcium (Ca), phosphate (Pi), intact parathyroid hormone (i-PTH), fibroblast growth factor 23 (FGF23), osteocalcin (OC), and cross-linked C-telopeptide of type 1 collagen (CTX-1); UUO group rats exhibited slight and inconsistent variations in the levels of Scr, BUN, Ca, Pi, i-PTH, FGF23, OC, and CTX-1 in serum. Histopathological analysis of the kidney showed that the UUO group rats suffered serious fibrosis and 5/6 Nx group rats exhibited severe focal calcification. Histopathological analysis of the femur showed that the AN group rats had minimal bone mineralization and that the 5/6 Nx group rats had overactive osteoclasts. Micro-CT revealed that the AN model had the most severe bone destruction and that the 5/6 Nx model had the least severe bone loss among the three models. The expression of cathepsin K in the femur was significantly increased in all models, while the expression of osterix in the femur was only significantly increased in the 5/6 Nx model. Conclusion: 5/6 Nx, AN, and UUO accompanied by a low-calcium and high-phosphorus diet successfully induced CKD-MBD in rats. The 5/6 NX model presented the progression of high-turnover bone disease, with consistency between biochemical indices in serum and histomorphometric analysis of the femur, and the AN and UUO models developed a severe deterioration in bone quantity and severe bone resorption; however, the changes in biochemical indices were subtle in the UUO model, and liver injury was obvious in the AN model.

Construction of artificial periosteum with methacrylamide gelatin hydrogel-wharton's jelly based on stem cell recruitment and its application in bone tissue engineering

The presence of periosteum can greatly affect the repair of a bone fracture. An artificial periosteum imitates the biological function of natural periosteum, which is capable of protecting and maintaining bone tissue structure and promoting bone repair. In our artificial periosteum, biocompatible methacrylate gelatin was used to provide the mechanical support of the membrane, E7 peptide added bioactivity, and Wharton's jelly provided the biological activity support of the membrane, resulting in a hydrogel membrane (G-E-W) for the chemotactic recruitment of bone marrow mesenchymal stem cells (BMSCs) and promoting cell proliferation and osteogenic differentiation. In an in vitro experiment, the G-E-W membrane recruited BMSCs and promoted cell proliferation and osteogenic differentiation. After 4 weeks and 8 weeks of implantation in a rat skull defect, the group implanted with a G-E-W membrane was superior to the blank control group and single-component membrane group in both quantity and quality of new bone. The artificial G-E-W membrane recruits BMSC chemotaxis and promotes cell proliferation and osteogenic differentiation, thereby effectively improving the repair efficiency of fractures and bone defects.

GMRS Oncological Prosthesis with a Porous Coating Collar: A Good Option for Revision of Aseptic Loosening in the Lower Extremity.

Revisions for oncological prosthesis are especially challenging due to the limited bone quantity and poor quality that the patients still possess. The aims of this study were to ask (1) what is the cumulative survival of the Global Modular Replacement System (GMRS) prosthesis after revision? and (2) what are the long-term functional outcomes of these patients? We retrospectively reviewed 16 patients who developed aseptic loosening of a lower extremity prosthesis. There were nine males and seven females with a mean age of 28 years (range, 14-55 years). The 5-year and 8-year survivorship of the prosthesis were calculated. Function outcome was evaluated according to the score of the Musculoskeletal Tumor Society (MSTS). At a mean of 90 months follow-up (range, 52-118 months), the cumulative survival of all revision prosthesis was 94% at both 5 and 8 years. There were two prosthesis failures including one infection and one repeated aseptic loosening. At the last follow-up, except for the infection case, 93.3% (14/15) of the patients did not develop repeated aseptic loosening. The mean MSTS score was 27.7 (range, 24-30). GMRS prosthesis demonstrated significant satisfactory long-term outcomes for revisions of lower extremity oncological prosthesis.

The Effect of General Bone Mineral Density on the Quantity and Quality of the Edentulous Mandible: A Cross-Sectional Clinical Study

Osteoporosis is a disease which is characterized by a decrease in general bone mineral density (BMD), resulting in decreased bone strength and an increased risk of bone fractures. The effect of reduced BMD on the jawbones is still not fully understood. The purpose of the study was to evaluate the impact of BMD on the quality and quantity of the edentulous mandible. The present study included 127 edentulous postmenopausal women who underwent cone beam computed tomography (CBCT) examinations. BMD measurements of the lumbar spine and femoral necks were performed by dual-energy X-ray absorptiometry. In the cross-sectional CBCT images, three different areas of the mandible (lateral incisor, first premolar, and first molar) were selected. The complete mandibular, trabecular, and cortical bone volumes were measured. All measurements were performed on the total mandibular area, and the basal and alveolar parts of the mandible. The volume of the cortical bone was reduced for females with reduced BMD in the lateral incisor and first premolar regions, both in the total mandibular area and in the basal part of the mandible. The trabecular bone volume statistically significantly increased when the BMD decreased in the complete mandibular area and the basal part of the mandible (linear regression). The total bone volume significantly decreased with a decrease in BMD in the basal part of the mandible. Reduced BMD has a negative effect on the quantity and quality of bone in the basal part of the edentulous mandible.

Safe sites for buccal shelf bone screw placement in various skeletal malocclusions: A CBCT study.

The mandibular buccal shelf area is an extra-alveolar anchorage site that has high quality and quantity of bone, provides biomechanical benefits and has low failure rates. It is essential to place the implant in the region of bone with optimal thickness. The aim of this study was to determine the suitable site of the mandibular buccal shelf for bone screw insertion at 90 degrees and 30 degrees angles of insertion and various heights, angulations, areas of the buccal shelf in prognathic and retrognathic mandibles, and vertical and horizontal growth patterns. In this retrospective study, we evaluated the cone-beam computed tomography (CBCT) images of 48 patients in the age range of 18-30 years, divided into four groups. Seven sectional sites were examined at 3, 5, and 7 mm from the alveolar crest at 90 degrees and 30 degrees. The angulation and area of the buccal shelf were examined. Cortical bone thickness increased distally from the first to the second molar in all four groups. The preferred site for buccal shelf implant placement was distal to the mandibular second molar. The maximum amount of cortical bone was observed distal to the second molar, 7 mm vertically from the alveolar crest, when the buccal shelf implant was placed at 30 degrees angulation to the long axis of the tooth.

Amniotic membrane as an accelator in mandibular bone defects repair

The fetal amniotic membrane is a biological graft with unique qualities which all lead to wound protection, reducing discomfort, and achieving adequate epithelialization. In this animal study, the second and third premolars of the mandible of 4 dogs were extracted. After 4 weeks, 20 mm of mandibular premolar site area were resected on both sides. The created defects on both sides were filled with xenograft. On one side, an amniotic membrane was placed over the graft particles and the reflected flap was sutured. The amount of bone formation in the defects was measured after 4 weeks for two of the dogs and after 8 weeks for the other two, using a caliper. Three histopathological samples from both sides were taken. The collected data were subjected to statistical analysis (Wilcoxon signed-rank and paired sample t-test) using SPSS software at a significant P = 0.05. In the test group, the quantity of bone was 56.81, whereas in the control group bone quantity was 37.38 with statistically significant differences (P = 0.025). In the amniotic membrane group, the inflammation intensity after the graft procedure was moderate (50%) in comparison to the control group where the inflammation was severe (62.5%) (P = 0.041). The amniotic membrane can induce positive osteoinduction effects and be helpful in repairmen of bone defects such as the natural periosteum.

Rehabilitation of Partially Edentulous Esthetic Zone with Custom-made Abutment in Young Patient

Abstract Implant positioning plays an important role in giving esthetics as well as in proper functioning of prosthesis. To achieve the best results, extensive evaluation and treatment planning are necessary for placing dental implants in an esthetically pleasing area. Important factors include the soft-tissue architecture, bone quantity and quality in both the horizontal and vertical planes. Thin labial cortical plate and gingival tissue in the upper anterior region are issues for esthetic outcomes. The use of high-performance ceramic material, the ability to customize the position, the angulation, the emergence profile, and the future position of the crown margin of the final restoration are all advantages of the custom abutment. Many cases of correcting the divergence between implants in total rehabilitation of the maxilla or mandible or in screw-retained single crowns are mentioned in the literature. This case report describes prosthetic rehabilitation of missing lateral teeth with customized abutments in young patients.

Frequency of surgical bone augmentation methods complementary to dental implant placement: A study evaluated with cone beam computed tomography.

The success of dental implants largely depends on the quantity and quality of available bone. Occasionally, it is necessary to perform additional surgical techniques alongside implant placement to increase the available bone volume and ensure the success and survival of treatments. The objective of this study was to evaluate, through cone beam computed tomography, the need for supplementary bone augmentation methods in implant placement. Additionally, the study aimed to assess the frequency of such techniques based on gender, anatomical sectors, and types of bone augmentation procedures. The analysis included 106 cone beam computed tomography images obtained from 77 patients over the age of 18 who sought oral rehabilitation with implants at the University Clinic of the Master's Program in Oral Implantology at the European University of Valencia. A total of 201 edentulous sextants were analyzed. It was observed that 63.68% of the sextants required a bone augmentation technique, and there was a statistically significant difference (p=0.039) regarding the need for supplementary techniques in women. The need for bone augmentation by sectors was most prevalent the horizontal type (48.11%) and in the mandible (29.41%). About crestal and lateral approaches for sinus elevation, there was a higher need for the lateral technique (49.38%), and a statistically significant difference was evident (p=0.015). A high frequency of bone augmentation need for implant placement was demonstrated. It was shown that some form of supplementary surgical method was required in implant placement (63.68%). The highest need for bone augmentation was observed in the posterior maxillary sector, primarily in the vertical type (29.27%), accompanied by lateral window sinus elevation technique (49.38%). Key words:Bone graft, Dental implant, Guided bone regeneration, Sinus floor augmentation, Cone beam computed tomography.

Study comparing the vibrations recorded by professional and non-professional male athletes in winter sports, skiing vs. snowboarding

Winter sports such as skiing and snowboarding are becoming increasingly popular among all age groups, as practicing these sports has seen an upward trend, which has led to an increase in the number of injuries and pathologies related to them. Practicing skiing/snowboarding entails a series of vibrations occurring in the equipment, their propagation along the kinetic chain impacting both in a positive and negative way the health of the person in question. The study was a comparison, skiing vs. snowboarding, between the vibrations experienced by professional and non-professional athletes, with the main objective of determining which of them produces greater vibrations and identifying the negative and positive effects they have. The study was performed under field conditions using sensors designed to record vibrations on the ski/snowboard (tip/nose and tail), as well as vibration sensors located in the ankle, knee, hip and lumbosacral areas, designed to record the propagation of vibrations along the kinetic chain. The results show a higher level of vibrations recorded on the ski than on the snowboard, while their transmission along the kinetic chain is inversely proportional. The conclusion relates to the choice of skiing/snowboarding. Therefore, due to the Whole-Body Vibration phenomenon, young people are more likely to choose snowboarding due to the possibility of increasing bone quality and quantity, while older people are rather fond of skiing, given its effect along the kinetic chain, which protects the skeletal system. Studies have provided evidence to suggest alpine skiing is an appropriate activity for elderly as a health-enhancing sport. Thus, perhaps alpine skiing could provide the physical activity needed to counteract age-related degradation processes and loss of function.

Lateral Window Maxillary Sinus Augmentation – Complications and Management

Introduction: The sinus lift procedure is the most predictable surgical intervention for enhancing bone quality and quantity in the posterior maxilla prior to the placement of endosseous dental implants. However, despite careful planning and precise surgical technique, several complications can arise. These include - haemorrhage, membrane perforation, infection, wound dehiscence, post operative pain, implant failure/ loss, graft loss, hematoma, barrier membrane exposure, oroantral fistula and sinusitis. Aim: The purpose of this report was to address the most common complications associated with the sinus lift procedure and discuss how to avoid and manage them when they occur. Methodology: A total of 140 articles from peer reviewed journals published in English from January 1986 to January 2023 were collected from a search performed using MEDLINE and PubMed. The keywords utilized were “dental implant”, “sinus augmentation”, “sinus complication”, “membrane perforation”, “bleeding – sinus augmentation”. Twenty-nine of the 140 articles satisfied the inclusion criteria and were utilized in this article. Results: Sinus membrane perforation is the most prevalent complication of maxillary sinus augmentation procedures, ranging from 11-60%. An incidence of 28% perforation rate is found. Bleeding was reported with an incidence of 2% of the sinus procedures performed. The use of piezoelectric devices as well as other measures play an important role in ensuring the stopping of bleeding. Conclusion: Proper planning and management of these complications will minimize the negative effects on therapy and allow for a successful implant result when placed in augmented maxillary sinuses.

Exosome-based bone-targeting drug delivery alleviates impaired osteoblastic bone formation and bone loss in inflammatory bowel diseases

Systematic bone loss is commonly complicated with inflammatory bowel diseases (IBDs) with unclear pathogenesis and uncertain treatment. In experimental colitis mouse models established by dextran sulfate sodium and IL-10 knockout induced with piroxicam, bone mass and quality are significantly decreased. Colitis mice demonstrate a lower bone formation rate and fewer osteoblasts in femur. Bone marrow mesenchymal stem/stromal cells (BMSCs) from colitis mice tend to differentiate into adipocytes rather than osteoblasts. Serum from patients with IBD promotes adipogenesis of human BMSCs. RNA sequencing reveals that colitis downregulates Wnt signaling in BMSCs. For treatment, exosomes with Golgi glycoprotein 1 inserted could carry Wnt agonist 1 and accumulate in bone via intravenous administration. They could alleviate bone loss, promote bone formation, and accelerate fracture healing in colitis mice. Collectively, BMSC commitment in inflammatory microenvironment contributes to lower bone quantity and quality and could be rescued by redirecting differentiation toward osteoblasts through bone-targeted drug delivery.

Spontaneous fractures and hypocuprosis in pen-backgrounded Holstein calves

Bone fractures are a frequent cause of limp in cattle, being pre-existing bone lesions among the predisposing factors. However, there is scant information about the natural occurrence of bone disease. This report aimed to describe an outbreak of spontaneous fractures associated with hypocuprosis in pen-backgrounded calves. Hind limp and irreversible recumbency were noticed in 9-month-old calves of a dairy farm from Córdoba province (Argentina). The issue was only evident in males fed a diet composed (DM) of 57% wet corn, 24% dry corn distiller grains, and 19% corn silage. No mineral mix was supplied. Accumulated morbidity and fatality rates were 5.8 and 100%, respectively. Two autopsies were performed, observing multiple femoral and rib fractures. Severe hypocupremia, very low copper levels in the liver and plasma, deficient dietary copper levels, normocalcemia, marginal hypophosphatemia, and high sulfate concentrations in the water supply were determined. Except for the decreased bone quantity and the multiple fractures, no bone lesion was observed, confirming osteoporosis as the pathological diagnosis, and hypocuprosis as the etiology.

A Fixed Reconstruction and Immediate Rehabilitation of Fully Edentulous Arch Using the All-on-Four Concept: Case Series

The implant survival largely depends on the mechanical setting in which they work as an independent entity. The implant design, number and position markedly affect the treatment plan. Deficient bone quantity and quality and presence of a vital anatomical landmark have often led the practitioners to conduct researches to find newer ways of implant insertion. One such technique is the 'All-On-4' concept, an alternative to the conventional implant therapy; lessens the amount of strain to the alveolar bone by increasing the antero-posterior spread with distal tilting the posterior implant. It is a cost-effective procedure that decreases the treatment time and the morbidity rate allowing a higher patient quality of life. The article demonstrates clinical cases describing rehabilitation of completely edentulous arches using the All-On-4 concept.

Mucogingival Conditions and Deformities Revisited. Review of their Current Classification and their Impact on Health and Function of Teeth

Mucogingival conditions and Deformities involve defects in the morphology, position, quantity of soft tissue and bone that support teeth, edentulous sites and dental implants. They significantly affect the supporting tissue around teeth and implants, and can affect the esthetics, health and function of them. The goal of this article is to review Mucogingival conditions and Deformities and their impact on teeth.

Is sclerostin antibody an effective agent for alveolar bone regeneration in animal models? A scoping review

Objectives
 The use of Sclerostin Antibody(Scl-Ab) as a bone anabolic agent has shown significant benefit in bone disorders in preclinical animal models and human clinical trials. Currently available evidence on the use of Scl-Ab in alveolar bone regeneration is limited to animal studies and hence this scoping review encompasses the animal studies conducted to ascertain the effectiveness of Scl-Ab on alveolar bone regeneration. 
 Materials and methods
 The search strategy was aimed to locate published animal studies in which the treatment arm includes Sclerostin antibody administration for alveolar bone preservation or regeneration. The search terms used were (((Animal model) OR Rodent) AND Alveolar bone defect) AND Anti sclerostin antibody) OR Sclerostin antibody) AND Alveolar bone regeneration) OR Bone regeneration) AND Bone fill. 
 Results
 Of the 559 results from Medline/PubMed, Scopus, Web of Science, Google scholar and additional articles from the references, six were included in the review. Scl-Ab was found to be effective in improving the bone quality and quantity. It was also observed that Scl-Ab was useful in reduced bone density associated with diseases and conditiona affecting osteoblast activity. 
 Conclusion
 The review concluded that Scl-Ab promotes alveolar bone augmentation and improves bone quality without surgical interventions.

Comparison of deconvoluted-convoluted reconstituted ultrasound signals with their experimental original in a porous composite, cancellous bone

Langton previously suggested that the transmission of ultrasound through cancellous bone, a complex structured porous composite, may be considered as an array of parallel sonic-rays. The transit time of each sonic-ray is determined by the proportion of bone tissue and bone marrow, with minimum (tmin) and maximum (tmax) values corresponding to entire bone tissue and bone marrow, respectively. Moreover, a transit time spectrum (TTS) describes the proportion of sonic-rays as a function of transit time, P(ti), detected within the aperture of the receive transducer. The TTS effectively serves as the time-integrated impulse response (IR) of a test sample, and may be derived by deconvolution of experimentally derived output oe(t) and input ie(t) ultrasound signals. Conversely, a reconstituted output signal, or(t), may be obtained by convolution of oe(t) and the test sample's TTS. This study aimed to test these deconvolution and convolution relationships utilizing natural tissue cancellous bone samples. 1 MHz broadband experimental output transmission ultrasound signals, oe(t), through 16 natural tissue samples of human femoral cancellous bone samples were recorded. Corresponding reconstituted output signals, or(t), were derived through a two-stage deconvolution-convolution process. A linear regression fit yielded a high degree of agreement between experimental and reconstituted ultrasound output signals, with an average coefficient of determination (R2) of 0.96 ± 0.03. This study therefore provides further evidence for the reliability and validity of ultrasound transit time spectroscopy (UTTS) as an assessment technique that provides quantitative information on both the quantity and quality of cancellous bone.

Comparison of 4- or 6-implant supported immediate full-arch fixed prostheses: A retrospective cohort study of 217 patients followed up for 3-13 years.

Choosing four or six implants to support immediate full-arch fixed prostheses (FAFPs) is still controversial worldwide. This study aims to analyze and compare the long-term results of All-on-4 and All-on-6. This retrospective cohort study enrolled 217 patients rehabilitated with 1222 implants supporting 271 FAFPs, including 202 prostheses supported by 4 implants (All-on-4 group) and 69 prostheses supported by 6 implants (All-on-6 group), and followed up for 3-13 years. Implant survival, prosthesis survival, complications, and implant marginal bone loss (MBL) were evaluated and compared between two groups. Patient characteristics including age, gender, jaw, opposite dentition condition, smoking habit, bruxism, bone quantity and quality, cantilever length (CL), prosthesis material, and oral hygiene were analyzed to assess their influence on the clinical results of the two groups. Six surgeons and three prosthodontists who performed FAFPs more than 5 years were invited for questionnaires, to assess patient- and clinician-related influences on implant number. In general, All-on-4 group indicated no significant difference with All-on-6 group in the implant survival (implant-level: hazard ratio [HR]=1.0 [95% confidence interval (CI): 0.8-1.2], P=0.96; prosthesis-level: HR=0.8 [95% CI: 0.3-1.8], P=0.54), prosthesis survival (odds ratio [OR]=0.8 [95% CI: 0.3-2.8], P=0.56), biological complications (OR=0.9 [95% CI: 0.5-1.8], P=0.78), technical complications of provisional prosthesis (OR=1.3 [95% CI: 0.7-2.3], P=0.42), technical complications of definitive prosthesis (OR=1.1 [95% CI: 0.6-2.2], P=0.33) and the 1st, 5th, and 10th year MBL (P =0.65, P =0.28, P =0.14). However, for specific covariates, including elderly patients, opposing natural/fixed dentition, smoking, bruxism, long CL, low bone density, and all acrylic provisional prostheses, All-on-6 was more predictable in some clinical measurements than All-on-4. The implant prosthodontists and the medium-experienced clinicians showed significant preference for All-on-6 (P <0.05). Based on this study, the long-term clinical results showed no significant difference between All-on-4 and All-on-6 groups in general. However, for some specific characteristics, All-on-6 seemed to be more predictable in some clinical measurements than All-on-4. For the clinicians' decision-making, medium-experienced clinicians and the implant prosthodontists showed significant preference for All-on-6.

Bone Modeling after Orthodontic Extrusion: A Histomorphometric Pilot Study.

During osteogenesis and bone modeling, high vascularity and osteoblastic/osteoclastic cell activity have been detected. A decrease in this activity is a sign of complete bone formation and maturation. Alveolar bone maturation seems to occur within weeks and months; however, the precise timing of the alveolar bone modeling is still unknown. The aim of this clinical pilot study was to investigate the bone modeling of neo-apposed tissue during orthodontic extrusive movements, through a histomorphometric analysis of human biopsies. This study was conducted on third mandibular molars sockets, and all teeth were extracted after orthodontic extrusion between 2010 and 2014. After different stabilization timings, extractions were performed, and a specimen of neo-deposed bone was harvested from each socket for the histomorphometric analysis. Histological parameters were evaluated to identify bone quantity and quality. This study included 12 teeth extracted from 9 patients. All specimens were composed of bone tissue. Bone samples taken after 1 and 1.5 months of stabilization presented remarkable percentages of woven bone, while after 2 months, a relevant decrease was observed. Histomorphometric analysis suggested that after orthodontic extrusion, a period of stabilization of 2 months allows the neo-deposed bone to mature.