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Rehabilitation of the edentulous maxilla with implant‐supported fixed dental prostheses can represent a significant clinical challenge due to limited bone availability and surgical access, among other factors. This review addresses several treatment options to replace missing teeth in posterior maxillary segments, namely the placement of standard implants in conjunction with maxillary sinus floor augmentation, short implants, tilted implants, and distal cantilever extensions. Pertinent technical information and a concise summary of relevant evidence on the reported outcomes of these different therapeutic approaches are presented, along with a set of clinical guidelines to facilitate decision‐making processes and optimize the outcomes of therapy. [ABSTRACT FROM AUTHOR]

Background: Anorganic bovine bone has been deeply studied for bone regeneration in the oral cavity. Different manufacturing processes can modify the final composition of the biomaterial and the responses that induce. Aim: To evaluate the physico‐chemical characteristics of a bovine bone mineral matrix and the clinical, radiographical, histological, and mRNA results after using it for maxillary sinus floor augmentation in humans. Materials and Methods: First, the physical–chemical characteristics of the biomaterial were evaluated by X‐ray powder diffraction, X‐ray fluorescence, and electron microscopy. A frequently used biomaterial with the same animal origin was used as comparator. Then, a clinical study was designed for evaluating clinical, radiographical, histological, and mRNA outcomes. Patients in need of two‐stage maxillary sinus floor augmentation were included in the study. Six months after the grafting procedure, a bone biopsy was collected for evaluation. Results: In terms of physico‐chemical characteristics, no differences were found between both biomaterials. Clinically, 10 patients were included in the study. After 6 months, clinical and radiographical data showed adequate outcomes for allowing implant placement. Histological, immunohistochemical and mRNA analyses showed that the biomaterial in use provides biological support to induce responses similar to those of other commonly used biomaterials. Conclusion: Bovine bone mineral matrix (Creos™ Xenogain) used as a single material for maxillary sinus floor augmentation shows adequate biological, clinical, and radiological outcomes. In fact, the results from this study are similar to those reported in the literature for another bovine bone‐derived biomaterial with whom it shares composition and micro‐ and nanoscale characteristics. [ABSTRACT FROM AUTHOR]

Aim: To compare the effectiveness of two xenografts for maxillary sinus floor augmentation in terms of clinical, radiographical, histologic, and molecular outcomes. Materials and methods: A split‐mouth randomized clinical trial was conducted at the University of Granada. Ten consecutive patients in need of bilateral two‐staged maxillary sinus floor augmentation were included. Each patient received both biomaterials (porcine bone mineral and anorganic bovine bone), which were randomly assigned for bilateral sinus augmentation. The maxillary autogenous bone scraped from the sinus access window was mixed with each xenograft at a 20:80 ratio. After a healing period of 6 months, bone biopsies were collected with a trephine during the implant placement in the regenerated area. Histologic, histomorphometrical, immunohistochemical, and molecular outcomes were analyzed. Clinical and radiographical data throughout the treatment phases were also evaluated. Results: The resulting anatomic features were similar between both groups. After six months of graft consolidation, the graft resorption rates were similar between both biomaterials. The histologic, histomorphometrical, and immunohistochemical results showed no statistical differences between groups. Conclusion: Anorganic bovine bone and porcine bone mineral combined with maxillary autogenous cortical bone show similar biologic and radiologic features in terms of biomaterial resorption, osteoconduction, and osteogenesis when used for maxillary sinus floor augmentation. [ABSTRACT FROM AUTHOR]

Purpose: Piezoelectric bone surgery was introduced into clinical practice almost 20 years ago as an alternative method for cutting bone in dental surgical procedures, in an attempt to reduce the disadvantages of using conventional rotary instruments. The aim of this Consensus Conference was to evaluate the current evidence concerning the use of piezoelectric surgery in oral surgery and implantology. Materials and methods: Three working groups conducted three meta-analyses with trial sequential analysis, focusing on the use of piezoelectric surgery in impacted mandibular third molar extraction, lateral sinus floor elevation and implant site preparation. The method of preparation of the systematic reviews, based on comprehensive search strategies and following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, was discussed and standardised. Results: Moderate/low evidence suggests that piezoelectric surgery is significantly associated with a more favourable postoperative course (less pain, less trismus) after impacted mandibular third molar extraction than conventional rotary instruments. Moderate evidence suggests that implants inserted with piezoelectric surgery showed improved secondary stability during the early phases of healing compared with those inserted using a drilling technique. Strong/moderate evidence suggests that piezoelectric surgery prolongs the duration of surgery in impacted mandibular third molar extraction, sinus floor elevation and implant site preparation, but it is unclear whether the slight differences in duration of surgery, even if statistically significant, represent a real clinical advantage for either operator or patient. Weak evidence or insufficient data are present to draw definitive conclusions on the other investigated outcomes. Conclusions: Further well-designed trials are needed to fully evaluate the effects of piezoelectric surgery, especially in implant site preparation and sinus floor elevation. [ABSTRACT FROM AUTHOR]

Purpose: The evidence pertaining to the contribution of the sinus membrane to new bone formation following maxillary sinus augmentation procedures is equivocal. The purpose of this study was to analyse the evidence currently available on the osteogenic capacity of the sinus membrane following maxillary sinus augmentation procedures, and the effect of local delivery of recombinant human bone morphogenic proteins (rhBMPs) on the bone-forming potential of the sinus membrane. Materials and methods: An electronic search was conducted using six different databases to identify controlled trials, prospective and retrospective cohort studies, case series and case reports, as well as preclinical (animal) studies reporting on new bone formation in close proximity with the sinus membrane after maxillary sinus augmentation procedures, assessed through histological and/or histomorphometrical evaluation, on the basis of pre-established eligibility criteria. Results: No clinical studies were identified. Twenty-six preclinical studies were included in the review. Nine of them supported the osteogenic potential of the sinus membrane, while eight reported no evidence of osteogenicity from the sinus membrane. The nine remaining studies reported on the local effect of rhBMPs. The majority of these nine studies reported enhanced new bone formation in the sinus membrane region. Conclusions: The sinus membrane contains pluripotent mesenchymal cells with the capacity to differentiate and participate in the process of new bone formation. However, the findings from the studies selected in this systematic review do not consistently support that the sinus membrane significantly contributes to new bone formation following maxillary sinus augmentation procedures. [ABSTRACT FROM AUTHOR]

Background: Poly (lactic‐co‐glycolic acid) (PLGA) is widely used for the development of delivery systems for drugs and therapeutic biomolecules in tissue engineering applications. Particles of biphasic calcium phosphate can be covered by PLGA to change their manipulating characteristics. Purpose: Aim of this study was to investigate the radiological and histomorphometric results of the use of PLGA‐coated biphasic calcium phosphate granules in sinus floor elevation and to analyze the underlying molecular processes by immunohistochemical staining. Materials and Methods: A randomized clinical study was designed to include patients in need of sinus floor elevation. Patients were assigned to receive either PLGA‐coated biphasic calcium phosphate particles (group I) or the equivalent but noncoated particles (group II). Cone beam computed tomography (CBCT) scans were performed before and 6 months after the procedure to assess the bone height gain. At the time of implant placement, bone core biopsies were obtained at the site of implant placement. Histological sections were subjected to histomorphometric and immunohistochemical evaluation of differentiation markers (Musashi‐1 [MSI1]). Results: No statistically significant differences were observed between groups for the radiologic parameters. No differences were observed histologically or histomorphometrically. However, PLGA‐coated particles (group I) were more colonized by MSI1‐positive osteoblast precursors (P = 0.0001, chi‐squared test) and were penetrated by more CD34‐positive vascular structures (P = 0.001, chi‐squared test) than noncoated particles (group II). Conclusions: PLGA‐coated particles are associated with more MSI11‐positive cells and more extensive microvascularization than noncoated particles. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to evaluate and compare the morphometric components and the histological properties of pristine bone and bone grafted with a biphasic ß‐tricalcium phosphate in humans using the maxillary sinus model. Reparative mesenchymal stem cells in the pristine bone and graft were also evaluated. Materials and Methods: For this prospective case series, sinus augmentation was performed using a biphasic ß‐tricalcium phosphate. After 6 months of healing, a core of remnant native alveolar bone and grafted bone was collected with a trephine. Histological, histomorphometrical, and immunohistochemical techniques were performed. Radiological analysis through cone beam computerized tomography was also conducted. Results: A total of 10 patients were enrolled in this study. Radiologically, patients showed an average increase of crestal bone of 8.03 ± 1.72 mm. Morphologically, the grafted area was composed by 34.93 ± 14.68% of new mineralized tissue, 9.82 ± 11.42% of remnant biomaterial particles, and 55.23 ± 11.03% non‐mineralized tissue. Histologically, we found no differences in the number of osteocytes per mm2 (p = 0.674), osteoblasts (p = 0.893), and blood vessels (p = 0.894) in the grafted area compared to the pristine bone. Differences were found on the number of osteoclasts (15.57 ± 27.50 vs. 5.37 ± 16.12, p = 0.027). The number of Musashi‐1 positive mesenchymal cells (239.61 ± 177.4 vs. 42.11 ± 52.82, p = 0.027) was also significantly higher in the grafted area than in the pristine bone. Conclusion: Biphasic ß‐tricalcium phosphate is a suitable biomaterial to be used in the formation of new bone in sinus floor elevation procedures in humans, not only from the histomorphometrical point of view, but also regarding the cellular and vascular quality of the regenerated bone. [ABSTRACT FROM AUTHOR]

Objective: To compare the clinical and histologic outcomes of two different grafting materials (allograft and xenograft) when combined with autogenous bone and covered with a collagen membrane for sinus augmentation. Material and Methods: A parallel case series of fourteen patients in need of a unilateral sinus augmentation was evaluated in this study. Seven patients received a graft composed by autologous cortical bone (ACB) and anorganic bovine bone in a ratio of 1:1; the other seven patients received ACB mixed with an allograft in the same ratio. Bone biopsies were obtained 6 months after sinus augmentation at the time of implant placement. Comparative histomorphometrical, histopathological, and immunohistochemical analyses were conducted and statistically analyzed. Results: After 12 months of functional loading, all implants in both groups were clinical and radiographically successful. Histomorphometrically, although the initial bone formation was not significantly different between groups (new mineralized tissue: 41.03(12.87)% vs. 34.50(13.18)%, p = .620; allograft vs. xenograft groups), the graft resorbed faster in the allograft group (remnant graft particles: 9.83[7.77]% vs. 21.71[17.88]%; p = .026; allograft vs. xenograft groups). Non‐mineralized tissue did not statistically differ either (49.00[14.32]% vs. 43.79[19.90]%; p = .710; allograft vs. xenograft groups). The histologic analyses revealed higher cellular content, four times more osteoid lines, and higher vascularization in the xenograft group. Musashi‐1 (mesenchymal stromal cell marker) was also more intensively expressed in the xenograft group (p = .019). Conclusions: Both composite grafts generate adequate substratum to receive dental implants after healing. Compared with the xenograft composite, allograft composite shows faster turnover and a quicker decrease in biological action after 6 months. [ABSTRACT FROM AUTHOR]

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Objective Cone-beam computed tomography ( CBCT) and radiographic outcomes of crestal sinus elevation, performed using mineralized human bone allograft, were analyzed to correlate results with maxillary sinus size. Material and methods A total of 60 sinus augmentations in 60 patients, with initial bone ≤5 mm, were performed. Digital radiographs were taken at surgical implant placement time up to post-prosthetic loading follow-up (12-72 months), when CBCT evaluation was carried out. Marginal bone loss ( MBL) was radiographically analyzed at 6 months and follow-up time post-loading. Sinus size ( BPD), implant distance from palatal ( PID) and buccal wall ( BID), and absence of bone coverage of implant (intra-sinus bone loss - IBL) were evaluated and statistically evaluated by ANOVA and linear regression analyses. Results MBL increased as a function of time. MBL at final follow-up was statistically associated with MBL at 6 months. A statistically significant correlation of IBL with wall distance and of IBL/mm with time was identified with greater values in wide sinuses ( WS ≥ 13.27 mm) than in narrow sinuses ( NS < 13.27 mm). Conclusions This study is the first quantitative and statistically significant confirmation that crestal technique with residual ridge height <5 mm is more appropriate and predictable, in terms of intra-sinus bone coverage, in narrow than in WS. [ABSTRACT FROM AUTHOR]

Purpose There is limited evidence available on the influence of residual ridge height ( RH) on bone density. Therefore, this study aimed to investigate the correlation between the atrophic posterior RH in the maxilla and its bone density as determined by microcomputed tomography (μ- CT). Material and Methods Thirty-two subjects with atrophic posterior maxilla of residual RH <8 mm were included in this study. A preoperative cone beam CT scan with a radiographic stent was taken for each patient. A bone core biopsy was thus obtained from the predetermined surgical site. Out of 32 biopsies, 27 were intact and sent for μ- CT analysis. Results A statistically significant positive correlation between bone volumetric fraction ( BV/ TV) and RH was identified ( r = 0.417, p = .03). A statistically significant negative correlation between trabecular pattern factor and RH was also found ( r = −0.415, p = .03). The rest of the morphometric parameters analyzed did not have any significant correlation to RH. Conclusion BV/ TV is potentially influenced by the residual bone height at the posterior maxilla. The lesser the RH, the lower the bone quantity and quality present. [ABSTRACT FROM AUTHOR]

Background: The aim of the present study is to examine the sinus lateral wall thickness (LWT) of atrophic posterior maxilla (<10 mm) of patients with complete and partial edentulism and determine the influence of residual ridge height (RH), sex, and age on maxillary LWT. Methods: Four hundred fourteen measures were taken from 140 consecutive patients that met the inclusion criteria. On the selected sagittal section, a built-in digital caliper recorded in millimeters the RH and LWT (a perpendicular line at 3, 5, 7, 10, 13, and 15 mm from the lowest point of the sinus floor). Edentulous spans were further classified as complete edentulous atrophic maxilla (CEM) and partial edentulous atrophic maxilla (PEM). The mixed linear model was used to test the effects of sex, type of edentulism, edentulous span, and RH on the measurement of the LWT of the sinus. Results: Mean LWT for PEM was 1.71 ± 0.12 mm, and for CEM, 1.57 ± 0.07 mm (P = 0.01). The mixed model yielded significant effect of edentulous span (P= 0.048) and interactions among type of edentulism and edentulous span (P<0.001) and edentulous span by RH (P<0.01). Age and RH were positively associated with LWT; however, they did not interact with RH, sex, or type of edentulism. RH has been shown to correlate with edentulous span (P<0.001) and type of edentulism (P= 0.01). The longer the edentulous span, the thinner the LWT. Similarly, RH was larger for PEM (6.85 ± 0.34 mm) than CEM (5.69 ± 0.26 mm). Conclusions: The maxillary sinus lateral wall tends to increase in thickness from the second premolar to the second molar and from 5 mm up to 15 mm. In addition, RH, presence of teeth adjacent to the edentulous atrophic ridge, and age were shown to influence maxillary sinus LWT. [ABSTRACT FROM AUTHOR]

Objectives Our objectives were to examine vascular and cellular colonization in anorganic bovine bone ( ABB) after 6 months of healing in human maxillary sinus augmentation grafts. Material and methods Fifty unilateral maxillary sinus augmentation procedures were performed on 50 consecutive patients. Bone cores were obtained through the implant receptor sites 6 months later and evaluated with morphological image analysis and immunohistochemical techniques. Results Image analysis revealed a mean of 35.44 ± 16% vital bone, 31.66 ± 15% non-mineralized tissue, and 32.72 ± 25% remnant ABB particles. In our patients, neovascularization in 46.3% of cases was demonstrated within ABB particles 6 months after sinus floor augmentation surgery. Neovascularization of ABB particles was inversely related to age, directly to osteoclast number per mm², and not influenced by habits or disease. CD44-positive cells colonization was found in 74% of cases. An important correlation was found regarding CD44 expression and number of vessel in ABB particles ( r = 0.624 P < 0.001, Pearson). Osteopontin expression was detected on the interstitial boundary of bone with ABB particles and within the osteocyte lacunae and bone canaliculi and was relationship with presence of CD44-positive cells inside ABB particles ( r = 0.388, P = 0.046, Pearson). Conclusion In conclusion, images compatible with osteone colonized by osteocytes CD44 positive and neovascularization in ABB particles were observed after 6 months of graft maturation. These biologic events have not previously been morphologically and immunohistochemically documented. [ABSTRACT FROM AUTHOR]

Purpose: Different biomaterials have been suggested for guided bone regeneration (GBR). These might show the ideal properties to let a new bone formation in the grafted area. Among these ideal features, it is essential their controlled resorption in order to be replaced for new vital bone. Bovine bone has been used widely as a good biomaterial for GBR, however there is still an interesting controversy about its resorbable capacity. In this sense, the objective of this study was to examine the behavior of anorganic bovine bone (ABB) in long-term maxillary sinus graft healing and study its relationship with morphological and morphometrical variables. Materials and Methods: Seventeen maxillary sinus augmentation procedures were performed in patients. Bone cores were obtained from implant receptor sites at 6 months, 3 years, and 7 years of implant placement for histological, morphometric, and immunohistochemical (tartrate resistant acid phosphatase [TRAP]/cathepsin K/CD68) studies. Results: The percentages of bone, ABB particles, connective tissue, osteocytes, and osteoblasts in maxillary sinus grafts were similar at 6 months, 3 years, and 7 years. A progressive and significant decrease was detected in osteoclasts ( p = .05, Kruskal-Wallis test), TRAP and cathepsin K expression ( p = .014 and p = .021, respectively), and osteoid lines ( p = .038). Conclusion: According to these data, a decrease in osteoclasts over time may, partially, explain the ABB persistence observed in core biopsies. Further studies with more cases and different graft maturation times are required to elucidate the resorption rates and cell events underlying these phenomena. [ABSTRACT FROM AUTHOR]

Introduction: Maxillary sinus augmentation is a predictable implant site development technique, although several local and systemic factors may influence outcomes. The aim of this study was to evaluate healing patterns and bone remodeling activity following the use of two different graft mixtures for maxillary sinus augmentation. Materials and methods: Patients in need of maxillary sinus augmentation were randomly assigned to two different groups. A graft mixture using a 50% autologous bone (AB) to 50% anorganic bovine bone (ABB) ratio was used in group 1, while a 20% AB to 80% ABB ratio was utilized for group 2. After a 6‐month healing period, bone core biopsies were harvested for histological, histomorphometrical, and immunohistochemical analyses. Results: Twenty‐eight subjects participated in this study. No statistically significant differences were found between groups in regards to vital bone and non‐mineralized tissue proportions. Higher number of osteoid lines (18.05 ± 10.06 in group 1 vs. 9.01 ± 7.53 in group 2; P=0.023) and higher cellularity, particularly regarding the number of osteocytes (631.85 ± 607.98 in group 1 vs. 219.08 ± 103.26 in group 2; P=0.002), were observed in specimens from group 1. Differences in expression patterns of osteopontin and tartrate‐resistant acid phosphatase were also detected between groups. Conclusion: AB to ABB ratio appears to influence bone remodeling patterns and cell content following maxillary sinus augmentation procedures. Similar proportion of vital bone was found in specimens obtained from both groups. More cellular presence was observed in samples containing higher proportions of AB. To cite this article: 
Galindo‐Moreno P, Moreno‐Riestra I, Avila G, Padial‐Molina M, Paya JA, Wang H‐L, O'Valle F. Effect of anorganic bovine bone to autogenous cortical bone ratio upon bone remodeling patterns following maxillary sinus augmentation.
Clin. Oral Impl. Res. 22, 2011; 857–864.
doi: 10.1111/j.1600‐0501.2010.02073.x [ABSTRACT FROM AUTHOR]

Background and objectives: Sinus augmentation is a procedure used for augmenting insufficient bone height that is often observed in the maxillary posterior areas. Many different techniques as well as bone graft regimens have been suggested for performing this procedure. It was the goal of this study to compare, clinically and histologically, two different composite grafting regimens used for sinus augmentation. Material and methods: Five patients, needing a bilateral sinus augmentation to allow implant placement, were recruited for this study. Right sinuses were grafted with cortical bone (collected from overlying the sinus membrane) and bovine hydroxyapatite (HA), while the left side sinuses were grafted with overlying autologous bone plus a bioglass (BG) material. Bone core biopsies were taken at 6 months after sinus graft or at the time of implant insertion. A waiting period of 6 additional months was granted to allow healing, before prosthetic restoration and functional loading. The level of peri-implant bone was evaluated 12 months after loading. A comparative histomorphometric analysis was conducted and a statistical analysis was performed. Results: All implants in both groups were functional after a 12-month loading period. No bone loss was observed radiographically or clinically in both groups. Histologic analysis revealed that both composite grafts had a high biocompatibility. In the bovine HA-containing group, minimal xenogenic graft absorption was noted. In contrast, BG group samples presented a high absorption rate with some remaining particles imbedded in new normal bone. Conclusions: Sinus augmentation using a combination of autogenous bone plus either bovine HA or BG is a predictable technique. [ABSTRACT FROM AUTHOR]

Short 6 mm dental implants are considered as an alternative to the maxillary sinus elevation and bone augmentation procedure where there is a reduced alveolar ridge height. The aim of this study was to compare the implant survival rate between short dental implants (6 mm) and regular length implants (11–13 mm) when placed in combination with bone grafting and loaded with a single non splinted crown, seven years after placing the implant. It was conducted as a controlled clinical study of 30 patients with partial edentulism in the posterior maxilla. The protocol included radiological and clinical evaluation of the C/I ratio (length of the superstructure divided by the length of the implant crestal part), marginal bone level (MBL), ultrasonography measurement of soft tissue surrounding implant (STT), patient-reported outcomes, and biological and technical complications. A total number of 28 implants (93%) remained integrated during follow-up period. MBL of 0.50 and 0.52 mm was observed for short implants and regular implants, respectively. MBL was checked for correlation with STT, and a negative correlation was found between MBL: STT. Our study has demonstrated a significantly lower implant survival rate for short implants compared to regular implants (87% compared to 100%). Despite the loss of several implants, good clinical results were achieved in the remaining implants in both groups. It is, therefore, worth considering short implants as an alternative to regular implants with a sinus lift surgery. [ABSTRACT FROM AUTHOR]