Augmented Bone Volume Research Articles

Quantitative analysis of change in bone volume 5 years after sinus floor elevation using plate-shaped bone substitutes: a prospective observational study

PurposeTricalcium phosphate (TCP) has osteoconductive ability and reportedly offers similar clinical results as autogenous bone grafts in dental implant treatment. However, few reports quantify temporal changes in augmented bone volume after sinus augmentation. We aimed to establish a three-dimensional (3D) quantification method to assess bone volume after sinus augmentation and to evaluate biocompatibility of the TCP plate.MethodsMaxillary sinus floor augmentation was performed employing the lateral window technique, and plate-shaped β-TCP (TCP plate) was used instead of granular bone grafting materials. After lifting the sinus membrane, the TCP plate was inserted and supported by dental implants or micro-screws. The changes in bone volumes in the maxillary sinus before and after surgery were recorded using cone-beam computed tomography, saved as Digital Imaging and Communications in Medicine-formatted files, and transformed to Standard Triangle Language (STL)-formatted files. Pre- and post-operative STL data of bone volume were superimposed, and the augmented bone volume was calculated. Moreover, changes in bone volumes, TCP plate resorption rates, and bone heights surrounding the implants were three dimensionally quantified.ResultsFifteen implants in nine subjects were included in this study. TCP plates secured long-term space making, with results similar to those of granular bone substitutes. Newly formed bone was identified around the implant without bone graft material. TCP plate was absorbed and gradually disappeared.ConclusionsA novel 3D quantification method was established to evaluate changes in bone volume. Clinical application of TCP plate in sinus augmentation could be a better procedure in terms of prognosis and safety.

Guided bone regeneration in implant dentistry: Basic principle, progress over 35 years, and recent research activities.

Bone augmentation procedures are frequent today in implant patients, since an implant should be circumferentially anchored in bone at completion of bone healing to have a good long-term stability. The best documented surgical technique to achieve this goal is guided bone regeneration (GBR) utilizing barrier membranes in combination with bone fillers. This clinical review paper reflects 35 years of development and progress with GBR. In the 1990s, GBR was developed by defining the indications for GBR, examining various barrier membranes, bone grafts, and bone substitutes. Complications were identified and reduced by modifications of the surgical technique. Today, the selection criteria for various surgical approaches are much better understood, in particular, in post-extraction implant placement. In the majority of patients, biodegradable collagen membranes are used, mainly for horizontal bone augmentation, whereas bioinert PTFE membranes are preferred for vertical ridge augmentation. The leading surgeons are using a composite graft with autogenous bone chips to accelerate bone formation, in combination with a low-substitution bone filer to better maintain the augmented bone volume over time. In addition, major efforts have been made since the millenium change to reduce surgical trauma and patient morbidity as much as possible. At the end, some open questions related to GBR are discussed.

A novel approach to determining augmented bone volume in intraoral bone block augmentation using an intraoral scanner: an in vitro study

IntroductionBone augmentation procedures are established tools for reshaping the alveolar ridge and increasing bone volume. Different approaches are being used to measure postoperative bone volume gain. This study aimed to develop an objective and automated volume measurement tool equally as precise as manual slice-by-slice annotation.Materials and methodsTo evaluate the proposed workflow, we performed an in vitro study with 20 pig mandibles that were grafted using three different grafting techniques—autogenous full block, split block bone and shell augmentation. The pig jaws were scanned pre- and postoperatively using an intraoral scanner. The resulting surface files (baseline, full block, split block, shell) were processed using the new volume-measuring workflow as well as using manual slice-by-slice annotation at baseline (t0) and at 6 months (t1) using the same population. Two TOSTs (Test of One-Sided Significance) and NHSTs (Null Hypothesis Significance Test) were used to compare the two workflows. The intra-rater reliability between t0 and t1 was determined using intraclass correlation coefficients.ResultsThe mean difference for the full block augmentation technique was − 0.015 cm3 (p < 0.001); for the split block technique, it was − 0.034 cm3p = 0.01, and for the shell technique, it was − 0.042 cm3. All results were statistically not different from zero and statistically equivalent to zero. The results also showed an excellent absolute intra-rater agreement.ConclusionsThe semiautomatic volume measurement established in this article achieves comparable results to manual slice-by-slice measuring in determining volumes on STL files generated by intraoral scanners and shows an excellent intra-rater reliability.Graphical

Sinus floor augmentation using crestal approach in conjunction with hydroxyapatite/cross-linked collagen sponge: A pilot study.

Different biomaterials were suggested for sinus floor augmentation (SFA). Recently, new materials were launched showing true bone formation without remnants. The aim of this prospective study was to evaluate an hydroxyapatite-based, sugar cross-linked collagen sponge (OSSIX™ Bone) in transcrestal SFA (t-SFA). Twenty-four patients with edentulous posterior maxilla and residual bone height (RBH) >4 mm underwent t-SFA with OSSIX™ Bone as grafting material and simultaneous implant placement. The implant Stability Quotient (ISQ) was measured by resonance frequency analysis (RFA) directly after implant insertion and at 6 months. Differences in bone height (BH) and volume were determined in CBCT and x-rays at baseline versus 1 year of follow-up. Graft volume was evaluated by tridimensional reconstructions. Linear regression analysis was used to evaluate the effect of bucco-palatal sinus dimension, RBH, and length of the implant protruding (PIL) into the sinus, on the graft height (GH) changes up to 1 year, and on the graft volume at 1 year. Autocorrelation between time lag and augmented bone volume was evaluated through time series analysis correlograms. Health-related quality-of-life outcomes were captured. Twenty-two patients completed the study. The mean RBH measured at baseline was 5.81 ± 2.2 mm. The mean graft volume was 1085.8 ± 733.4 mm3 . The mean GH, measured in the immediate post-operative period, at 6 and 12 months respectively, was 7.24 mm ±1.94; 6.57 mm ± 2.30; 5.46 mm ± 2.04. The mean ISQ measured after the implant placement was 62.19 ± 8.09, and 6 months later was 76.91 ± 4.50. There was a significant correlation between buccolingual dimension and graft volume at 1 year. Neither buccolingual volume nor RBH had a significant effect on GH change, while the PIL showed a significant positive correlation (P = 0.02 and P = 0.03 at 6 and 12 months, respectively). The correlograms indicated no significant correlation, meaning that there is no tendency for graft volume to increase or decrease over time, therefore suggesting graft stability, at least up to one year of follow-up. 86% of patients had no chewing interference. Within the limitations of the study, OSSIX™ Bone could be considered a valid material for SFA due to its manageability and its positive results in promoting new bone formation with long-term stability. T-SFA is confirmed as a less invasive and less painful method.

Use of hyaluronic acid for regeneration of maxillofacial bones

Hyaluronic acid (HA) has been widely used in medicine and is currently of particular interest to maxillofacial surgeons. Several applications have been introduced, including those in which HA is used as a scaffold for bone regeneration, either alone or in combination with other grafting materials, to enhance bone growth. This review aims to analyze the available literature on the use of HA for maxillofacial bone regenerative procedures including socket preservation, sinus augmentation, and ridge augmentation. Medline and PubMed databases were searched for relevant reports published between January 2000 and April 2021. Nine publications describing the use of HA to augment bone volume were identified. Although further studies are needed, these findings are encouraging as they suggest that HA could be used effectively used, in combination with graft materials, in maxillofacial bone regenerative procedures. HA facilitates manipulation of bone grafts, improves handling characteristics and promotes osteoblast activity that stimulates bone regeneration and repair.

Use of hyaluronic acid for regeneration of maxillofacial bones: A review

Purpose: Hyaluronic acid (HA) has been used widely in medicine and is currently of particular interest to maxillofacial surgeons. Several applications have been introduced, including those in which HA is used as a scaffold for bone regeneration both alone and in combination with other grafting materials to enhance bone growth. This review aims to analyze the available literature on the use of HA for maxillofacial bone augmentation for prosthetic-driven implant placement procedures. This article also aims to review the specific advantages, applications, and graft materials associated with HA use. Materials and Methods: Medline and PubMed databases were searched for relevant reports published between January 2000 and December 2021. Results and Discussion: Nine publications describing the use of HA to augment bone volume were identified. Administration of HA facilitates surgical manipulation of the graft and promotes osteoblast activity that stimulates bone regeneration and repair. Conclusion: Although further studies are needed, these findings are encouraging, as they suggest that HA might be used effectively together with additional graft materials in maxillofacial bone augmentation procedures.​

Long-term clinical and radiographic evaluation after maxillary sinus floor augmentation with octacalcium phosphate-collagen composite: A retrospective case series study.

The purpose of this study was to evaluate, using clinical and radiological assessments, the stability of dental implants 5years after maxillary sinus floor augmentation with octacalcium phosphate-collagen composite (OCP/Col). Maxillary sinus floor augmentation was performed through a lateral window approach. Depending on the height of the host bone, a simultaneous approach (≥5mm) or a staged approach (less than 5mm) was employed. The primary outcome was the evaluation of clinical dental implant conditions such as infection, peri-implantitis, dental implant stability, pain, and paresthesia. Secondary outcomes were the evaluation of the augmented bone volume, change rate of augmented bone volume, vertical bone height, and marginal bone loss around dental implant fixture. The conditions of all dental implants were uneventful throughout the follow-up period. Augmented bone volume and changing rate of augmented bone volume were essentially unchanged following maturation of the OCP/Col-derived new bone. The change rate of new bone volume was 21.9% in the simulated approach and 16.8% in the staged approach at 1year and 5years postoperatively. The reduction rate in vertical bone height was 7.1% in the simultaneous approach and 7.5% in the staged approach between 1year and 5years postoperatively. Mean marginal bone loss was 1.76mm with the simultaneous approach, and 0.50mm with the staged approach at 5years postoperatively. In conclusion, the success of dental implants 5years after sinus floor augmentation by OCP/Col implantation was clarified by both clinical and radiological evaluations.

Safety and feasibility assessment of biodegradable poly (l-lactic acid/ε-caprolactone) membrane for guided bone regeneration: A case series of first-in-human pilot study

Background/purposeGuided bone regeneration (GBR) is the most popular technique for alveolar ridge augmentation in implant dentistry, and resorbable cell barrier membrane, made of collagen, is widely used. We tried to develop a new resorbable cell barrier membrane from an animal-free product. This study aimed to investigate the safety and feasibility for clinical application of poly (l-lactic acid/ε-caprolactone) [P (LA/CL)] membrane, a novel biodegradable synthetic material used for GBR. Materials and methodsPatients who required horizontal bone augmentation (≥3 mm implant exposure) for implant treatment were included in the study. P (LA/CL) membrane was used simultaneously with implant placement to achieve bone augmentation by GBR. The occurrence of adverse events was assessed until the follow-up period of a second surgical procedure. The amount of bone augmentation was assessed by means of cone-beam computed tomography, and implant stability was assessed by measuring the implant stability quotient (ISQ). Student's t-test was used and the level of significance was set at p < 0.05. ResultsThis first-in-human study comprised five participants. Adverse events were observed in three of five patients, and a cause-and-effect relationship of the membrane could not be denied in one of them. Good bone formation was observed in the GBR region of all five patients. The ISQ during the second surgical procedure indicated good osseointegration in all the patients. ConclusionThe application of P (LA/CL) membrane for bone augmentation with GBR made it possible to maintain the augmented bone volume without causing any irreversible adverse events. However, further investigations on humans are required to confirm the safety of this biomaterial.

Autogenous bone augmentation from the zygomatic alveolar crest: a volumetric retrospective analysis in the maxilla

BackgroundAutogenous bone augmentation is the gold standard for the treatment of extended bone defects prior to implantation. Bone augmentation from the zygomatic crest is a valuable option with several advantages, but the current literature for this treatment is scant. The aim of this study was to evaluate the increase in bone volume after locoregional bone augmentation using autogenous bone from the zygomatic alveolar crest as well as the complications and success rate.ResultsAnalysis of the augmented bone volume in seven patients showed a maximum volume gain of 0.97 cm3. An average of 0.54 cm3 of autogenous bone (SD 0.24 cm3; median: 0.54 cm3) was augmented. Implantation following bone augmentation was possible in all cases. Complications occurred in three patients.ConclusionThe zygomatic alveolar crest is a valuable donor site for autogenous alveolar onlay grafting in a locoregional area such as the maxillary front. Low donor site morbidity, good access, and its suitable convexity make it a beneficial choice for autogenous bone augmentation.

Volumetric Changes Following Lateral Guided Bone Regeneration.

Resorbable membranes are well described and employed for horizontal guided bone regeneration (GBR). However, the currently available literature does not provide information on the bone volumetric changes during the healing that follows GBR procedures and dental implant placement. Therefore, the aim of this pilot study was to initially analyze the volumetric bone changes after treating pristine edentulous mandibular defects with lateral GBR using freeze-dried bone allograft (FDBA) and collagen resorbable membrane. Six patients were selected for the analysis. Clinical changes in bone volume before and after GBR were measured. In addition, digital volumetric analysis of the augmented ridges was performed preoperatively, as well as 4 and 6 months after the GBR procedure. At the time of dental implant placement, bone cores were collected during the osteotomy for histologic analysis. Data on volume changes showed a mean of 297.5 ± 134 mm3 augmented bone volume at 4 months with 5% ± 3.78% resorption from 4 to ≥ 6 months. Histologic bone core analysis showed 44.9% plusmn; 5.1% mineralization in the area of augmentation. Within the limitations of this pilot study, resorbable membranes exhibited reliability for GBR in intercalated mandibular defects, providing sufficient bone volume gain at ≥ 6 months for implant stabilization and limited resorption during graft healing.

Effect of a Single Injection of Benidipine-Impregnated Biodegradable Microcarriers on Bone and Gingival Healing at the Tooth Extraction Socket.

Objective: A dihydropyridine-type calcium channel blocker, benidipine (BD), is extensively used in hypertension therapy. In vitro study reported BD promoting bone metabolism. We evaluated the effect of sustained release of BD-loaded poly(lactic-co-glycolic acid) (PLGA) microcarriers on the promotion of bone and gingival healing at an extraction socket in vivo. In addition, the effect of BD on osteoblasts, osteocytes, fibroblasts, and epithelial cells was evaluated in vitro. Approach: The maxillary first molar of rats was extracted. Next, PLGA microcarriers containing BD were directly injected into the gingivobuccal fold as a single dose. After injection, bone and soft-tissue healing was histologically evaluated. Effect of BD on proliferation, migration, and gene expression of gingival and bone cell was also examined in vitro. Results: After tooth extraction, BD significantly augmented bone volume and density, and also epithelial wound healing. During in vitro studies, BD promoted significant proliferation and migration of fibroblasts and epithelial cells. Real-time RT-PCR revealed that BD upregulated messenger RNA expression of Ahsg (alpha 2-HS glycoprotein) and Csf2 (colony-stimulating factor 2) in osteoblasts. Innovation: The prevention of bone and soft-tissue reduction associated with tooth extraction has been eagerly anticipated in the field of dentistry. This study first reported the effect of BD on extraction socket healing. Conclusion: A single dose of topically administered BD-loaded PLGA microcarriers promoted bone and soft-tissue healing at the extraction site of tooth.

Sclerostin and DKK1 Inhibition Preserves and Augments Alveolar Bone Volume and Architecture in Rats with Alveolar Bone Loss

Alveolar bone is a mechanosensitive tissue that provides structural support for teeth. Alveolar bone loss is common with aging, menopause, tooth loss, and periodontitis and can lead to additional tooth loss, reduced denture fixation, and challenges in placing dental implants. The current studies suggest that sclerostin and DKK1, which are established osteocyte-derived inhibitors of bone formation, contribute to alveolar bone loss associated with estrogen ablation and edentulism in rats. Estrogen-deficient ovariectomized rats showed significant mandibular bone loss that was reversed by systemic administration of sclerostin antibody (SAB) alone and in combination with DKK1 antibody (DAB). Osteocytes in the dentate and edentulous rat maxilla expressed Sost (sclerostin) and Dkk1 (DKK1) mRNA, and molar extraction appeared to acutely increase DKK1 expression. In a chronic rat maxillary molar extraction model, systemic SAB administration augmented the volume and height of atrophic alveolar ridges, effects that were enhanced by coadministering DAB. SAB and SAB+DAB also fully reversed bone loss that developed in the opposing mandible as a result of hypo-occlusion. In both treatment studies, alveolar bone augmentation with SAB or SAB+DAB was accompanied by increased bone mass in the postcranial skeleton. Jaw bone biomechanics showed that intact sclerostin-deficient mice exhibited stronger and denser mandibles as compared with wild-type controls. These studies show that sclerostin inhibition, with and without DKK1 coinhibition, augmented alveolar bone volume and architecture in rats with alveolar bone loss. These noninvasive approaches may have utility for the conservative augmentation of alveolar bone.

Synthetic Parathyroid Hormone May Augment Bone Volume in Autogenous Grafts: A Study in Rats.

Synthetic parathyroid hormone [PTH(1-34)] has been investigated for its benefits on bone healing and osteoporosis treatment; however, there is little information regarding bone grafts. This study therefore investigates the effect of PTH(1-34) on autogenous bone graft healing. Bone grafts were harvested from the calvarium of rats with a trephine bur (3-mm internal diameter) and placed on the cortex near the mandible angle with a titanium screw. Animals were randomly assigned to group 1 (control): subcutaneous injections of saline solution, three times a week (n = 15); group 2: 2 μg/kg PTH(1-34), three times a week (n = 15); and group 3: 40 μg/kg PTH(1-34), three times a week (n = 15). Thirty days postoperatively, the animals were killed, and specimens (implant + bed + graft) were removed and used for undecalcified sections. The following histometric parameters were evaluated: total bone thickness (TT) (bed + gap + graft), graft thickness (GT) (adjacent to the implant), bone-to-implant contact (BIC), and bone area (BA) (within the limits of the threads). Five additional animals were sacrificed immediately after surgery (zero hour) to register bed and graft sizes before healing. Group 3 showed significantly greater bone gain compared with groups 1 and 2 (TT and GT, P <0.05). In relation to initial thickness (zero hour), groups 1 and 2 showed a total decrease in volume of 15.91% and 20.83%, respectively, whereas group 3 showed a slight bone gain (1.21%). Data analysis revealed a significant difference for group 3 compared with groups 1 and 2 (P <0.01). No differences were observed for BIC and BA (P >0.05). Systemic administration of PTH(1-34) augmented bone volume in autogenous grafts.

Predictability of staged localized alveolar ridge augmentation using a micro titanium mesh.

The aim of this study is to retrospectively evaluate the success rate of staged localized alveolar ridge augmentation using titanium micromesh. In addition, the factors that influenced the success were analyzed. Twenty-three alveolar ridges (posterior mandible 12, anterior maxilla 7, anterior and posterior maxilla 3, and posterior maxilla 1) were augmented using titanium micromesh and were retrospectively assessed. Thirty sites were judged as successful with a success rate of 56.6% (posterior mandible 58.3%, anterior maxilla 57.1%, anterior and posterior maxilla 33.3%, and posterior maxilla 100%). The span of the augmentation site was significantly correlated with the success rate (goodness test of fit for chi-square, p < 0.05). The success rate was low if infection of the grafted material was observed, while the exposure of titanium mesh had no negative impact. This limited study suggested that the predictability of augmented bone volume in staged alveolar ridge augmentation using titanium micromesh was not sufficient to expect an ideal and planned implant placement. The success was influenced by the distance of the augmentation site and the infection of the graft material, which were associated with moderate to severe vertical ridge resorption and/or mechanical and functional loading on the surgical site.

Effects of different biomaterials on augmented bone volume resorptions.

The aim of this study was to assess the effects of platelet-rich fibrin (PRF), deproteinized bovine bone graft (DBBG), and biphasic calcium phosphate (BCP) biomaterials on total volume resorption levels and bone augmentation. Nine New Zealand rabbits were divided into three groups (PRF, DBBG, and BCP). Two titanium barriers were fixed bilaterally to each rabbit's calvarium; a total of 18 titanium barriers were used. All barriers were removed on the 90th day. Computed tomography (CT) images of the animals were taken on the 90th, 120th, 150th, and 180th days. When the resorption level of the total volume in all groups on the 120th, 150th, and 180th days was compared with that of the 90th day, no significant differences among all groups were found in all intervals. According to the total volume on the 90th and 180th days, statistically significant differences between groups DBBG and BCP were not found; however, statistically significant differences were found between group PRF and the others groups (P<0.001). On the other hand, there were statistically significant differences in regenerated bone area between group PRF and BCP. According to the results of this study, grafts such as DBBG or BCP must be used to augment bone volume sufficiently in guided bone regeneration.

Adjunctive Orthodontic Applications in Dental Implantology

Implant placement is often necessitated for replacement of teeth with pathologically damaged alveolar bone due to periodontitis or traumatic injury. Surgical augmentation of resorbed bone has many limitations, including lower efficacy of vertical augmentation than horizontal augmentation, as well as morbidity associated with grafting procedure. Orthodontic therapy has been proposed as a useful method for augmenting the resorbed alveolar bone and reforming aesthetically appealing gingival margin, prior to implant placement. This narrative review summarizes the available evidence for the application of orthodontic strategies that can be used as adjunct in selected cases to augment bone volume for the future implant site and maintain space for the prosthetic parts of the implant. These are (1) orthodontic extrusion of compromised teeth to generate vertical bone volume and enhance gingival architecture, (2) tooth preservation and postponing orthodontic space opening to maintain bone volume in future implant site, (3) orthodontic implant site switching to eliminate the deficient bone volume or risky implant sites, and (4) the provision of a rigid fixed-bonded retainer to maintain the implant site. Although there are no randomized controlled clinical trials to evaluate the efficacy of orthodontic therapy for implant site development, clinical case reports and experience document the efficacy of orthodontic therapy for this application.

Autologous Ilium Grafts: Long‐Term Results on Immediate or Staged Functional Rehabilitation of Mandibular Segmental Defects Using Dental Implants after Tumor Resection

It is a challenge for clinicians to restore oral function in patients with segmental defects of the mandible because of tumor extirpation. Dental implant therapy following vascularized autologous ilium grafts is an effective method to restore oral function in patients with mandibular segmental defects. The aim of this retrospective study was to investigate the long-term clinical outcomes of ilium grafts combined with immediate or staged mandibular dental implant therapy to restore craniofacial defects resulting from tumor resection. Over a 5-year period (2000-2004), 32 patients who underwent mandibular segmental resection for tumors were treated with vascularized ilium grafts to augment bone volume. Seventeen patients received phase I therapy (immediate placement of implants), and 15 patients underwent phase II therapy (delayed placement of implants). A total of 110 dental implants were placed in these patients for mandibular restoration of the defective areas. Information regarding implant success and survival rates, marginal bone loss, soft tissue inflammation, complications of prosthesis, and patient satisfaction for the 8 to 12 years following oral reconstruction was obtained from patient records. Although there was mild evidence of bone graft resorption, the vascularized autogenous ilium bone grafts were successful in all patients. The cumulative patient survival and success rate of the implants were 96.4% and 91.8%, respectively. The mean peri-implant bone resorption ranged from 1.0 to 1.2 mm over the 8- to 12-year follow-up period. The annual mean number of complications/repairs was from 0.11 to 0.07 per patient during the 8- to 12-year follow-up. Over 80% of the patients were fully satisfied with their restoration of oral function. This study demonstrates that reconstruction of mandibular segmental defects because of resection of mandibular tumors using dental implants therapy combined with vascularized autogenous ilium grafts is an effective method to restore oral function.

Effects of the Permeability of Shields with Autologous Bone Grafts on Bone Augmentation

The objective of this study was to histologically evaluate and compare the effects of the permeability of shields on bone augmentation in a rabbit calvarial model. Twelve adult male Japanese white rabbits were used for the study. Each received four titanium cylinders, which were placed into perforated slits made in the outer cortical bone of the calvaria and filled with autologous iliac bone. The tops of the cylinders were randomly covered with the following test materials: (1) uncovered (control), (2) a titanium mesh, (3) an expanded polytetrafluoroethylene (e-PTFE) membrane, or (4) a titanium plate. After 8 weeks, the animals were sacrificed, and ground sections were obtained for histomorphometric analysis. There was no significant difference in augmented bone volume among all groups. However, the distribution of augmented bone in the cylinders differed among the groups. In the uncovered control, there was significantly less augmented bone in the upper third of the cylinder than in the middle or lower thirds. Findings were similar for the titanium mesh group and the e-PTFE membrane group, with significantly less augmented bone in the upper third than in the middle or lower thirds. In the titanium plate group, there was no significant difference in augmented bone among the upper, middle, and lower thirds. The differences among the upper, middle, and lower thirds of the cylinder were smaller in the order of titanium plate, e-PTFE membrane, titanium mesh, and uncovered control. The use of low-permeability shields resulted in small differences in the distribution of bone structure in the present bone augmentation model.

Evaluation of bone volume changes after sinus floor augmentation with autogenous bone grafts

The aim of this study was to establish an objective method for quantitative evaluation of bone volume change after sinus augmentation. 11 sinuses in 9 patients were evaluated by computed tomography images taken before treatment (T0), and 3 months (T1) and at least 1 year (T2) after sinus augmentation. Based on the 3D digital subtraction technique, augmented bone images were extracted and bone volumes were calculated from voxel numbers of the extracted images. The mean augmented bone volumes at T1 and T2 were 2.46cm3 and 1.85cm3, respectively. These bone volume changes were statistically significant and the mean bone volume change±SE was −24.8%±6.1%. Loss of augmented bone was observed in all except one of the patients. The correlation coefficient between bone volume change and elapsed time was −0.64, which was statistically significant and indicated that bone resorption progressed with elapse of time after sinus augmentation. The authors’ method of analysis enabled visualization of augmented bone and objective assessment of bone volume change. Within the limited number of cases, the present investigation demonstrated a significant decrease in augmented bone volume between 3 and 23 months after surgery.

Evaluation of three‐dimensional changes after sinus floor augmentation with different grafting materials

The aim of this retrospective investigation was to assess the dimensional stability of different grafting materials after maxillary sinus floor augmentation with computed tomography (CT) scans. Two postoperative CT scans were available from 16 patients who had undergone maxillary sinus lift procedures. The first scan was made within a few days after the surgical intervention and the second one >6 months later. A total of 25 maxillary sinuses were augmented with different materials before implant insertion by lateral antrostomy in a staged approach. The volume of bone formation was calculated using the Somaris Sienet Magic View software. Based on volumetric measurements of the augmented domes derived from the image sections, shrinkage was about 26%. The mean of the augmented bone volume was 3.02 cm(3) (1.4-5.56 cm(3); SD+/-1.18 cm(3)) as determined in the first CT scan. The respective mean volume in the second CT scan amounted to 2.28 cm(3) (0.92-4.46 cm(3); SD+/-1.07 cm(3)). Within the limits of our descriptive and analytic study, the results indicate a significant reduction of the graft volume after maxillary sinus augmentation. Further prospective studies will have to evaluate the quantitative changes of different bone graft materials for maxillary sinus augmentation procedures in order to improve long-term implant stability.