Analysis of the healing process in sinus bone grafting using various grafting materials

Effects of Polydeoxyribonucleotide (PDRN) on Endosinus Bone Regeneration Following Sinus Floor Elevation: An Experimental In Vivo Pilot Study

OBJECTIVE

To determine the effect of polydeoxyribonucleotide (PDRN) on endosinus bone regeneration in a rabbit sinus model at sequential healing time points.

MATERIALS AND METHODS

Eighteen New Zealand white rabbits were used. Bilateral sinus floor elevation (SFE) was performed. Two groups were randomly assigned to each sinus: (1) test group, in which SFE was performed using collagenated bone substitute material soaked with PDRN (concentration 2.0 mg/mL, dose 0.5 mL), and (2) control group, in which SFE was performed using collagenated bone substitute material only. The experimental animals were sacrificed at 2, 4, and 8 weeks (n = 6 at each healing time point). Microcomputed tomography (micro-CT), histologic, and histomorphometric analyses were performed.

RESULTS

The micro-CT analysis revealed statistically significant increases in the mineralized tissue volume between 4 and 8 weeks (p < 0.05). Histologically, no specific intergroup difference was found in the pattern of new bone formation. Histomorphometrically, the area of newly formed bone (NB) was larger in the test group than in the control group at all healing time points (1.4 vs. 1.2 mm2 at 2 weeks, 3.4 vs. 1.9 mm2 at 4 weeks, and 5.7 vs. 4.5 mm2 at 8 weeks; median value), but the difference was statistically significant only at 4 weeks (p < 0.05). NB in set regions of interest (ROI_C, ROI_W, and ROI_M) tended to be greater in the test group than in the control group without statistical significance (p > 0.05).

CONCLUSIONS

PDRN appeared to enhance new bone formation at all healing time points, but the improvement was statistically significant only at 4 weeks.

Effect of a synthetic hydroxyapatite-based bone grafting material compared to established bone substitute materials on regeneration of critical-size bone defects in the ovine scapula

Lately, the potential risk of disease transmission due to the use of bovine-derived bone substitutes has become obvious, demonstrating the urgent need for a synthetic grafting material with comparable bioactive behaviour and properties. Therefore, the effect of a synthetic hydroxyapatite (HA) (Osbone®) bone grafting material on bone regeneration was evaluated 2 weeks, 1 month, and 3, 6, 12 and 18 months after implantation in critical-size bone defects in the ovine scapula and compared to that of a bovine-derived HA (Bio-Oss®) and β-tricalcium phosphate (TCP) (Cerasorb® M). New bone formation and the biodegradability of the bone substitutes were assessed histomorphometrically. Hard tissue histology and immunohistochemical analysis were employed to characterize collagen type I, alkaline phosphatase, osteocalcin, as well as bone sialoprotein expression in the various cell and matrix components of the bone tissue to evaluate the bioactive properties of the bone grafting materials. No inflammatory tissue response was detected with any of the bone substitute materials studied. After 3 and 6 months, β-TCP (Cerasorb® M) showed superior bone formation when compared to both HA-based materials (3 months: β-TCP 55.65 ± 2.03% vs. SHA 49.05 ± 3.84% and BHA 47.59 ± 1.97%; p ≤ 0.03; 6 months: β-TCP 62.03 ± 1.58%; SHA: 55.83 ± 2.59%; BHA: 53.44 ± 0.78%; p ≤ 0.04). Further, after 12 and 18 months, a similar degree of bone formation and bone-particle contact was noted for all three bone substitute materials without any significant differences. The synthetic HA supported new bone formation, osteogenic marker expression, matrix mineralization and good bone-bonding behaviour to an equal and even slightly superior degree compared to the bovine-derived HA. As a result, synthetic HA can be regarded as a valuable alternative to the bovine-derived HA without the potential risk of disease transmission.

Effect of carbonate apatite as a bone substitute on oral mucosal healing in a rat extraction socket: in vitro and in vivo analyses using carbonate apatite

Background

Low bone quantity and quality are serious problems that affect the prognosis of implants in the cosmetic field. Therefore, artificial bone substitutes are frequently used. However, whether there is a difference in the effect of either bone substitute on soft tissue healing is unclear given their greatly different absorbability. In this study, we used hydroxyapatite (HAp) and carbonate apatite (CO₃Ap) as bone substitutes to analyze the epithelial and connective tissue healing after tooth extraction.

Methods

In vitro, oral mucosa-derived epithelial cells (OECs) collected from 4-day-old Wistar rats were seeded on HAp or CO₃Ap and evaluated for adhesion, proliferation, migration, apoptosis, and morphology. Fibroblasts (FBs) were also analyzed for their ability to express collagen. In vivo, the extraction of maxillary right first (M1) and second molars (M2) of 6-week-old male Wistar rats was performed, followed by insertion of HAp or CO₃Ap granules into the M1 and M2 sites. The oral mucosal healing process was then evaluated histochemically after 7 and 14 days.

Results

In vitro, high collagen expression by FBs in the CO₃Ap group was observed and the surface analysis showed spreading of the FBs on the CO₃Ap surface. However, the activity of OECs was suppressed on CO₃Ap. Two weeks after CO₃Ap implantation, soft tissue healing was observed, and recovery of the connective tissue was observed on the remaining CO₃Ap.

Conclusions

Our results suggest that the formation of soft tissues, including connective tissue, was promoted by CO₃Ap in the extraction socket within a short period.

Implant Placement With Graftless Sinus Floor Elevation via the Lateral Approach: A Case Series With 4 Years Post-Loading Radiographical Outcomes and Implant Survival Rate

ABSTRACT

The purpose of the present study was to evaluate the radiographical outcomes, survival rate, and amount of bone formation around implants placed during graftless lateral sinus lift approach (GLSLA). Five patients (6 sinus augmentations) were consecutively treated with GLSLA. After Schneiderian membrane elevation and implant insertion, only blood clot was left to fill the new sinus compartment. After 4 months of healing, implants were functionally loaded. In all cases, samples were taken for biopsy at the time of second-stage surgery. The radiographical marginal bone variations and apical bone gain were assessed using cone beam-computed tomography taken 4 months after the surgery (at crown insertion) and after 4 years of loading. A total of 14 implants were placed in a mean initial residual bone height of 3.1 mm (range 1.6-4 mm). No failure was recorded, and all the implants were successfully loaded yielding a 100% survival rate. Vital bone formation was 33% according to the histomorphometry data. Four years after loading the mean radiographic bone remodeling was 1.3 mm. The mean ridge height was 7.6 mm and the mean apical bone gain amounted for 3.8 mm. Within the limitations of this study, the placement of dental implants in conjunction with GLSLA seems to be feasible and accompanied by high implant survival rate.

Implant placement with sinus floor elevation via the lateral approach using only absorbable collagen sponge: 12-month post-loading radiographical outcomes and implant survival rate

PURPOSE

The purpose of the present study was to evaluate the radiographical outcomes and survival rate of implants placed during graftless lateral sinus lift approach (GLSLA) using an absorbable collagen sponge.

MATERIALS AND METHODS

Fourteen patients (14 sinus augmentations) were consecutively treated with GLSLA. After Schneiderian membrane elevation and implant insertion, only collagen sponges were used to fill the new sinus compartment. After 4 months of healing, implants were functionally loaded. The radiographical marginal bone variation and apical bone gain were assessed on periapical radiographs taken 4 months after the surgery (at crown insertion) and at 12 months post-loading.

RESULTS

A total of 41 implants were placed in a mean initial residual bone height of 3.5 mm (range 1.6-6.7 mm). No failure was recorded and all the implants were successfully loaded with fixed prosthesis. Twelve months post-loading the mean radiographic bone remodeling was 2.22 mm. The mean ridge height was 8.4 mm and the mean apical bone gain amounted for 4.4 mm.

CONCLUSIONS

Within the limitations of this study, the placement of dental implants in conjunction with GLSLA using only a collagen sponge to fill the sinus compartment seems to be feasible and accompanied by a high implant survival rate. Further studies on a large population and with a longer follow-up are warranted to drawn definitive conclusions.

Sinus membrane elevation and implant placement

Sinus Schneiderian membrane elevation surgery is widely performed for dental implant placement in the maxillary posterior region. With regard to sinus elevation surgery, various complications can occur and lead to implant failure. For successful implants in the maxillary posterior region, the clinician must be well acquainted with sinus anatomy and pathology, a variety of bone graft materials, the principles of sinus elevation surgery, and prevention and management of complications.

Ridge preservation of compromised extraction sockets applying a soft cortical membrane: A canine proof-of-principle evaluation

OBJECTIVES

To explore whether placement of a soft cortical membrane can restore and regenerate the original alveolar ridge contour in deficient sockets.

MATERIALS AND METHODS

One Beagle dog was used in this proof-of-principle evaluation. In a first intervention, a standardized buccal dehiscence defect was artificially created at the distal roots of the 3rd and 4th mandibular premolars. Four weeks later, following endodontic treatment of the mesial roots, teeth were hemisected and the distal roots were extracted without raising a flap. A cortical membrane (Lamina®, Osteobiol) was placed outside of the bony envelope of the extraction socket to rebuild the buccal bone contour. Afterwards, sockets were filled with a collagen-modified porcine bone graft material (Gen-Os®, Osteobiol) to the level of the surrounding bone height. The socket orifice was closed with a porcine dermal matrix (Derma®). After four months, block specimens containing the socket-sites and remaining roots were retrieved, histologically processed and analyzed.

RESULTS

Surgery and post-operative healing were uneventful. Histologically, bone formation under the membrane was found, i.e. bony protrusions and ossicles by osteoblasts could be identified. Concomitantly, the membrane showed clear signs of degradation. Bone substitute was well integrated in newly formed bone and resorption of particles was found.

CONCLUSION

Three major observations were made in the present proof-of-principle study: (i) regeneration of a compromised socket seems possible when applying the presented approach, (ii) the soft cortical membrane was sufficiently stable to allow for the establishment of the contour and to inhibit soft tissue invasion and (iii) the applied xenogenic graft material was undergoing remodelling processes while allowing adequate bone regeneration.

Bone Formation in Grafts with Bio-Oss and Autogenous Bone at Different Proportions in Rabbit Calvaria

Background

The aim of this study was to assess the volumetric stability and bone formation in grafts with Bio-Oss and autogenous bone at different proportions in rabbit calvaria. Material and Methods. Ten rabbits received four titanium cylinders in their calvaria and randomly divided into the following groups: Group I: Bio-Oss (100%), Group II: Bio-Oss (75%) + autogenous bone (25%), Group III: Bio-Oss (50%) + autogenous bone (50%), and Group IV: autogenous bone (100%). After twelve weeks, the animals were euthanized, and samples were collected for clinical and histological analysis.

Results

Clinical analysis showed that Groups I (90.43 ± 8.99) and II (90.87 ± 7.43) had greater dimensional stability compared to Group IV (P=0.0005). Histologically, Groups I, II, and III showed areas of bone formation with particles of biomaterial remaining in close contact with the newly formed bone. However, there were no significant differences between the groups regarding the newly formed bone area.

Conclusion

It was concluded that the use of Bio-Oss either alone or associated with the autogenous bone at a proportion of 25% showed superior dimensional stability compared to the use of autogenous bone in the proposed experimental model.

A Human Clinical and Histomorphometrical Study on Different Resorbable and Non-Resorbable Bone Substitutes Used in Post-Extractive Sites. Preliminary Results

Background: The healing of sockets following teeth extraction results in a marked reduction of the height and width of the ridge. This in vivo study aims to assess and compare the efficacy of calcium sulphate (CS) and sintered nano-hydroxyapatite (NHA) in postextraction sockets. Materials and Methods: 10 subjects were enrolled for single or multiple tooth extraction and implant placement. Each site was randomly assigned to one of four groups and filled with CS, NHA, a combination of CS and NHA, or left to normal healing. After five months tissue samples were harvested from the extraction sites and prepared for histological investigations. Results: Histomorphometric analysis showed that the average percentages of vital bone was 13.56% ± 13.08% for CS, 17.84% ± 7.32% for NHA, 58.72% ± 8.77% for CS + NHA%, and 80.68% ± 21.8% for the controls; for the connective tissue the results were 33.25% ± 35.75% for CS, 55.88% ± 21.86% for NHA, 17.34% ± 8.51% for CS + NHA, and 22.62% ± 0.52% for the controls; for residual biomaterial the results were 0.56% ± 0.52% for CS group, 21.97% ± 0.79% for NHA, and 47.54% ± 20.13% for CS + NHA. Conclusions: Both biomaterials led to bone tissue formation after five months of healing. The combination of the biomaterials presented a better behavior when compared to the individual application.

Biological and technical outcomes of restored implants after maxillary sinus augmentation-Results at 1-year loading

OBJECTIVE

To report biological and technical outcomes of implant-supported restorations placed into previously maxillary sinus floor augmentation using the lateral wall approach (MSA) using anorganic bovine bone mineral (ABBM) + autogenous bone (AB) (control group) or collagen-stabilized ABBM (test group).

MATERIALS AND METHODS

Single implant was placed 6 months after MSA in 27 control and 26 test patients. Fixed restorations were delivered 12 weeks later and reviewed 12 months after function. Outcomes measured included implant survival, marginal bone levels (DIB), peri-implant parameters, and incidence of biological and technical complications.

RESULTS

Seven patients (three control, four test group) did not return for their 1-year review. No significant inter-group differences were noted for all parameters. At baseline (3 months after implant placement), a mean(SD) marginal bone loss of 0.66 mm (0.40) and 0.77 mm (0.48) from the implant shoulder was recorded in the control and test group, respectively. After 12 months of loading, a mean (SD) additional marginal bone loss of 0.32 mm (0.24) and 0.35 mm (0.23) was noted in the control and test group, respectively. Peri-implant mucositis (≥1 site BOP) was diagnosed in 62.9% of control and 69.23% of test patients. No peri-implantitis was diagnosed. Screw retention and single crowns predominated. Technical complications mostly comprised of ceramic veneer chipping and were noted in 7.4% of control and 11.54% of test patients.

CONCLUSION

Based on a short observation period, implant reconstruction of the partially edentulous posterior maxilla after MSA using ABBM + AB or collagen-stabilized ABBM led stable marginal bone levels, high prevalence of peri-implant mucositis, and low rates of technical complications.

Dental alloplastic bone substitutes currently available in Korea

As dental implant surgery and bone grafts were widely operated in Korean dentist, many bone substitutes are commercially available, currently. For commercially used in Korea, all bone substitutes are firstly evaluated by the Ministry of Health and Welfare (MOHW) for safety and efficacy of the product. After being priced, classified, and registration by the Health Insurance Review and Assessment Service (HIRA), the post-application management is obligatory for the manufacturer (or representative importer) to receive a certificate of Good Manufacturing Practice by Ministry of Food and Drug Safety. Currently, bone substitutes are broadly classified into C group (bone union and fracture fixation), T group (human tissue), L group (general and dental material) and non-insurance material group in MOHW notification No. 2018-248. Among them, bone substitutes classified as dental materials (L7) are divided as xenograft and alloplastic bone graft. The purpose of this paper is to analyze alloplastic bone substitutes of 37 products in MOHW notification No. 2018-248 and to evaluate the reference level based on the ISI Web of Knowledge, PubMed, EMBASE (1980–2019), Cochrane Database, and Google Scholar using the criteria of registered or trademarked product name.

Comparative Histological and Histomorphometric Results of Six Biomaterials Used in Two-Stage Maxillary Sinus Augmentation Model after 6-Month Healing

Objectives

To evaluate the performances of six different bone substitute materials used as graft in maxillary sinus augmentation by means of histological and histomorphometric analysis of bone biopsies retrieved from human subjects after a 6-month healing period.

Materials and Methods

Six consecutive patients (3 males, 3 females, aged 50-72 years), healthy, nonsmokers, and with good oral hygiene, presenting edentulous posterior maxilla with a residual bone crest measuring ≤ 4 mm in vertical height and 3 to 5 mm in horizontal thickness at radiographic examination, were selected to receive sinus augmentation and delayed implant placement. Under randomized conditions, sinus augmentation procedures were carried out using mineralized solvent-dehydrated bone allograft (MCBA), freeze-dried mineralized bone allograft (FDBA), anorganic bovine bone (ABB), equine-derived bone (EB), synthetic micro-macroporous biphasic calcium-phosphate block consisting of 70% beta-tricalcium phosphate and 30% hydroxyapatite (HA-β-TCP 30/70), or bioapatite-collagen (BC). After 6 months, bone core biopsies were retrieved and 13 implants were placed. Bone samples were processed for histological and histomorphometric analysis. CT scans were taken before and after surgery. After 4 months of healing, patients were restored with a provisional fixed acrylic resin prosthesis, as well as after further 2-4 months with a definitive cemented zirconia or porcelain-fused-to-metal crowns.

Results

There were no postoperative complications or implant failures. The histological examination showed that all biomaterials were in close contact with newly formed bone, surrounding the graft granules with a bridge-like network. No signs of acute inflammation were observed. The histomorphometry revealed 20.1% newly formed bone for MCBA, 32.1% for FDBA, 16.1% for ABB, 22.8% for EB, 20.3% for HA-β-TCP 30/70, and 21.4% for BC.

Conclusions

Within the limitations of the present investigation, all the six tested biomaterials showed good biocompatibility and osteoconductive properties when used in sinus augmentation procedures, although the FDBA seemed to have a better histomorphometric result in terms of newly formed bone and residual graft material. This trial is registered with ClinicalTrials.gov Identifier (Registration Number): NCT03496688.

Hydraulic Transcrestal Sinus Lift: Different Patterns of Elevation in Pig Sinuses

PURPOSE

The aim of this study was to evaluate different patterns of sinus membrane elevation in pig jaws.

MATERIALS AND METHODS

A total of 30 pig jaws (60 sinuses) were used for the present investigation. The hydraulic Crestal Approach Sinus kit was used to elevate sinus membrane, and different elevation patterns were recorded.

RESULTS

There were 4 different scenarios of membrane separation patterns: center dome-shaped elevation, off-center dome-shaped elevation, horizontally spreading membrane elevation, and perforation. The incidence of each different type was 35.0% (n = 21) in center dome-shaped separation, 51.7% (n = 31) in off-center dome-shaped separation, 10.0% (n = 6) in horizontally spreading separation, and 3.3% (n = 2) in membrane perforation.

CONCLUSION

Different patterns of membrane elevations are observed in pig sinuses and introduced in this study. The off-center dome-shaped elevation was the most common pattern followed by the center dome-shaped elevation and horizontally spreading elevation, respectively.

Maxillary sinus lift using osteoinductive simvastatin combined with β-TCP versus β-TCP - a comparative pilot study to evaluate simvastatin enhanced and accelerated bone formation

PURPOSE

The aim of this study was to evaluate available bone quality and quantity after performing sinus augmentation using simvastatin/β-TCP combination versus β-TCP alone.

MATERIALS AND METHODS

This study included eight sinus lift procedures conducted on six patients. The sinuses were divided into two equal groups. The patients were recalled one, two weeks two, five, nine months post-operatively for post-operative evaluation. Radiographic evaluation involved cone beam computed tomography (CBCT) radiographs taken for every patient one week and nine months post-operatively to evaluate the changes in bone height, while histomorphometric evaluation involved transcortical bone biopsies taken after nine months during the second-stage surgery for implant placement.

RESULTS

The histomorphometric results showed that the amount of newly formed bone was higher in the simvastatin group when compared to the β-TCP group nine months after the surgery; the difference between the two groups was statistically significant. On the other hand, the radiographic evaluation showed that the rate of resorption of the simvastatin group was found to be higher than the control group; however, the difference between both groups was statistically insignificant.

CONCLUSION

These results showed that Simvastatin is safe to be used in sinus lift with promising osteoinductive capacity, yet further studies using larger sample size is needed.

A prospective controlled trial comparing xenograft/autogenous bone and collagen-stabilized xenograft for maxillary sinus augmentation-Complications, patient-reported outcomes and volumetric analysis

OBJECTIVE

Compare maxillary sinus augmentation (MSA) using two different materials-anorganic bovine bone mineral (ABBM) + autogenous bone (AB) (control group) vs. collagen-stabilized ABBM (test group) in terms of complications, patient-reported outcome measures (PROMs) and volumetric analysis.

MATERIALS AND METHODS

Sixty patients underwent sinus augmentation (30 control + 30 test group). Intra- and postoperative complications were recorded. PROMs measured the impact of grafting on daily activities, pain and morbidity. CT scans were used to measure graft volume, ridge height, material selection and degree of contact of graft-to-surrounding sinus walls. Dental implant placement parameters were also recorded.

RESULTS

All complications were minor and did not prevent completion of the augmentation or subsequent implant placement. Schneiderian membrane perforation was the most frequently encountered complication. Both treatment groups reported moderate limitation in the 1st 48 hr post-surgery but little or none by day 3 or 4. Jaw opening, chewing and bruising were significantly higher in the control group. The impact on work and social life was moderate initially but reduced to little or none by the 2nd day. Mild to moderate pain and interference to daily activities were reported for the first 3 days requiring the use of NSAIDs only. A mean graft volume of 1.46 cm³ (±0.77) was calculated in the control group and 1.27 cm³ (±0.65) in the test group. Extent of contact between graft and surrounding sinus walls had a significant impact on bone volume. Shorter (8 mm) implants were utilized more frequently in the test group, which was also more likely to require additional vertical augmentation, but this was not statistically significant.

CONCLUSION

MSA using a lateral wall approach is safe and associated with mild to moderate pain and restrictions to daily activities for 48-72 hr. Patients' reports of morbidity were greater with autogenous bone harvesting. Collagen-stabilized ABBM provides comparable bone volume to AB + ABBM that is sufficient for placement of implants of adequate size with no need for further vertical augmentation. Engaging the surrounding sinus walls had a significant positive impact on graft volume.

Attributes of Bio-Oss® and Moa-Bone® graft materials in a pilot study using the sheep maxillary sinus model

BACKGROUND AND OBJECTIVE

The aim of this pilot study was to characterize surface morphology and to evaluate resorption and osseous healing of two deproteinated bovine bone graft materials after sinus grafting in a large animal model.

MATERIAL AND METHODS

Surfaces of a novel particulate bovine bone graft, Moa-Bone^® were compared with Bio-Oss^® using scanning electron microscopy. Six sheep then had maxillary sinus grafting bilaterally, covered with BioGide^® . Grafted maxillae were harvested after 4, 6 and 12 weeks. Healing was described for half of each site using resin-embedded ground sections. For the other half, paraffin-embedded sections were examined using tartrate resistant acid phosphatase staining for osteoclast activity, runt-related transcription factor2 immunohistochemistry for pre-osteoblasts and osteoblasts and proliferating cell nuclear antigen for proliferative cells.

RESULTS

Moa-Bone^® had a smoother, more porous fibrous structure with minimal globular particles compared with Bio-Oss^® . After 4 weeks, woven bone formed on both grafts and the Moa-Bone^® particles also showed signs of resorption. After 12 weeks, Moa-Bone^® continued to be resorbed, however Bio-Oss^® did not; both grafts were surrounded by maturing lamellar bone. Moa-Bone^® was associated with earlier evidence of runt-related transcription factor 2-positive cells. Moa-Bone^® but not Bio-Oss^® was associated with strong tartrate resistant acid phosphatase-positive osteoclasts on the graft surface within resorption lacunae at both 4 and 6 weeks post-grafting.

CONCLUSION

Both materials supported osseous healing and maturation without inflammation. Moa-Bone^® showed marked osteoclast activity after 4 and 6 weeks and demonstrated positive attributes for grafting, if complete remodeling of the graft within the site is desired. Further optimization of Moa-Bone^® for maxillofacial applications is warranted.

Sinus Augmentation by Platelet-Rich Fibrin Alone: A Report of Two Cases with Histological Examinations

In sinus floor augmentation of an atrophic posterior maxilla, platelet-rich fibrin (PRF) has been used as a graft material. We herein report two cases with histological evaluations of PRF after the surgery. The first case was a 28-year-old female with an atrophic right posterior maxilla who was treated with sinus floor augmentation and simultaneous implant placement using PRF as the sole graft material in our hospital. Twenty-four months after surgery, the implant was unfortunately removed because of occlusal overloading by parafunctional habits. During implant replacement, a tissue sample was obtained from the site of augmentation with PRF and was evaluated histologically. The second case was a 58-year-old man with severe alveolar atrophy of the right maxilla who underwent lateral sinus augmentation using only PRF in a two-stage procedure in our hospital. Samples were obtained at the second-stage surgery and histological examinations were performed. As a result, new bone formation was confirmed histologically in both cases. Our findings show that the use of PRF as a graft material during sinus floor augmentation induces natural bone regeneration.

Histomorphometric Analysis of Contaminated Autogenous Tooth Graft Materials After Various Sterilization

PURPOSE

The purpose of this study was to evaluate histomorphometrically contaminated autogenous tooth graft materials, which were resterilized.

MATERIALS AND METHODS

The intentional defects (diameter: 8 mm, depth: 4 mm) were formed around implant fixture on the iliac crest of 6 mongrel dogs. Autogenous tooth graft materials were made by extracted premolars. After the contamination of the tooth materials, graft procedure was performed; no contaminated group (control group), contaminated groups (nonsterilization group [group 1], ethylene oxide [EO] gas group [group 2], and autoclave group [group 3]). The bone-to-implant contact (BIC) and the new bone formation rate (NBFR) were evaluated after sacrifice.

RESULTS

The BIC and NBFR of groups 1 and 3 were significantly lower than the control group after 4 weeks. The BIC and NBRF of group 3 were significantly lower than the control group after 8 weeks. However, the BIC and NBRF of group 2 was not significantly different comparing with the control group after 4 and 8 weeks.

CONCLUSION

Sterilization using EO gas may be more favorable than high-pressure sterilization in cases the reuse of contaminated autogenous tooth graft materials.

A histomorphometric assessment of collagen-stabilized anorganic bovine bone mineral in maxillary sinus augmentation - a prospective clinical trial

OBJECTIVE

To histomorphometrically compare the use of collagen-stabilized anorganic bovine bone (ABBM-C) (test) to anorganic bovine bone + autogenous bone (ABBM + AB) (control) in maxillary sinus augmentation.

MATERIALS AND METHODS

Forty (n = 40 sinuses) patients underwent sinus augmentation and received either control (20 sinuses) or test bone graft (20 sinuses). Bone samples were harvested from the augmented sinuses 5 months postgrafting. The samples were processed for histomorphometry, which assessed within the primary region of interest (ROI-1), the area fraction of new bone (%NB), graft particle osseointegration (% OI), residual graft (%RG), and soft tissue components (% STM). The same analysis was also carried out in a second region of interest (ROI-2) located in a zone 1 mm proximal to the previous maxillary sinus floor.

RESULTS

In both ROI-1 and ROI-2, the mean % NB, %RG, and %STM in the control group were similar to mean values in the test group. The % OI was significantly greater in the control group (42.0 +/- 26.8) when compared to the test group (19.6 +/- 27.3) in ROI-2 (P < 0.05). No statistically significant differences were seen when ROI-1 and ROI-2 were compared except for improved %OI in ROI-2 in the control group. The mean proportion of lamellar bone to woven bone in the control group (1.22 ± 1.48) was significantly greater than the test group (0.38 ± 0.29) (P < 0.05).

CONCLUSION

ABBM-C exhibited very similar histomorphometric parameters to the composite graft of ABBM + AB. The ABBM + AB group was more mature as indicated by the significantly greater proportion of lamellar bone when compared to the ABBM-C. Improved % OI was seen in the zone proximal to the resident bony floor in the ABBM + AB group. Based on histological assessment, ABBM-C is a suitable bone substitute for the purposes of maxillary sinus augmentation. Its clinical utility may be indicated in cases of sinus membrane perforation and insufficient autogenous bone in the local area.

Histological and Histomorphometric Human Results of HA-Beta-TCP 30/70 Compared to Three Different Biomaterials in Maxillary Sinus Augmentation at 6 Months: A Preliminary Report

OBJECTIVE

The aim of this investigation was to examine the bone regenerative potential of newly biphasic calcium phosphate ceramics (HA-β-TCP 30/70), by assessing histological and histomorphometric results of human specimens retrieved from sinuses augmented with HA-β-TCP 30/70, and comparing them to anorganic bovine bone (ABB), mineralized solvent-dehydrated bone allograft (MSDBA), and equine bone (EB), after a healing period of 6 months.

MATERIALS AND METHODS

Four consecutive patients with edentulous atrophic posterior maxilla were included in this report. A two-stage procedure was carried out for sinus augmentation with HA-β-TCP 30/70, ABB, MSDBA, and EB. After 6 months, specimens were retrieved at the time of implant placement and processed for histological and histomorphometric analyses.

RESULTS

At histological examination, all biomaterials were in close contact with the newly formed bone and showed the same pattern of bone formation; the grafted granules were surrounded by a bridge-like network of newly formed bone. A limited number of ABB particles were partially covered by connective tissue. The histomorphometric analysis revealed 30.2% newly formed bone for Ha-β-TCP 30/70, 20.1% for ABB, 16.4% for MSDBA, and 21.9% for EB.

CONCLUSIONS

Within the limitations of the present investigation, these results support the successful use of HA-β-TCP 30/70 for sinus augmentation.

Evaluation of bone formation after grafting with deproteinized bovine bone and mineralized allogenic bone

PURPOSE

The purpose of this study was to evaluate the ability of new bone formation of deproteinized bovine bone (Bio-Oss) and mineralized allogenic bone (Tutoplast).

MATERIALS AND METHODS

Sixty rats were divided into control and experimental groups (groups 1 and 2): control group, unfilled control; group 1, Bio-Oss; group 2, Tutoplast, respectively. The animals were killed after 6 and 12 weeks, and newly formed bone was analyzed histomorphometrically.

RESULTS

In the control group, some new bone formed in the rim of the defect area. In the group 1, newly formed bone was thinner than the adjacent normal bone, and Bio-Oss particles were observed. In the group 2, showed a pattern of gradual fusion with adjacent bone, as well as particles in some areas, similar to the Bio-Oss-treated group. In the 12-week groups, the amount of new bone formation was significantly higher in the experimental groups than in the control group, and it was significantly higher in group 2 than in group 1.

CONCLUSION

Although Tutoplast and Bio-Oss graft materials seem to be useful for bone grafts, Tutoplast showed more active new bone formation than Bio-Oss.

Platelet-Rich Fibrin in Maxillary Sinus Augmentation: A Systematic Review

The aim of this study was to systemically assess the efficacy of platelet-rich fibrin (PRF) on maxillary sinus augmentation using the lateral approach. A PubMed search and a hand search of relevant journals and the bibliographies of selected articles were performed. Clinical studies using PRF with open maxillary sinus augmentation were included. The search provided 290 titles; only 8 studies fulfilled the inclusion criteria. Identified studies showed heterogeneity regarding surgical technique, grafting material, implant placement time, protocol, outcome measures, healing time for biopsy, and implant placement, as well as follow-up period. From the 8 identified studies, 3 studies used PRF as a sole filling material, whereas the other 5 studies used PRF with bone substitutes. PRF showed promising results as a sole filling material for sinus lift with simultaneous implant placement, and PRF seemed to accelerate maturation of a demineralized freeze dried bone allograft. Conversely, it had no effect on deproteinized bovine maturation. PRF fibrin membranes represent an easy and successful method to cover the sinus membrane or osteotomy window.

Resorption of bone graft after maxillary sinus grafting and simultaneous implant placement

OBJECTIVES

The purpose of this study was to evaluate the sinus bone graft resorption over 3 years after two-stage implant placement.

MATERIALS AND METHODS

The subjects for this study included 30 patients whose maxillary posterior ridges were too atrophic for implants. Bone-added osteotome sinus floor elevation was used in 15 maxillary sinuses, while the bone graft by lateral approach technique was used in 25 maxillary sinuses. The height from the top of the fixture to the sinus floor was estimated immediately after implant placement and the follow-up period was over 3 years. The surgery was classified with two groups: sinus bone grafting with and without autogenous bone. All implants were placed simultaneously.

RESULTS

The mean vertical bone loss was 3.15±2.95 mm. The survival rate of implants was 94.7%.

CONCLUSION

The amount of bone resorption was not significantly associated with the surgical methods, the type of bone graft materials used, or sinus perforation during surgery.

Risk Factors for Wound Dehiscence after Guided Bone Regeneration in Dental Implant Surgery

Purpose:

The purpose of this study was to evaluate risks for wound dehiscence after guided bone regeneration (GBR) in dental implant surgery.

Methods:

Patients who received dental implant therapy with GBR procedure at Seoul National University Bundang Hospital (Seongnam, Korea) from June 2004 to May 2007 were included. The clinical outcome of interest was complications related to dental implant surgery. The factors influencing wound dehiscence, classified into patient-related factors, surgery-related factors and material-related factors, were evaluated.

Results:

One hundred and fifteen cases (202 implants) were included in this study. Wound dehiscence (19.1%) was considered a major complication. The risk of wound dehiscence was higher in males than in females (odds ratio=4.279, P =0.014). In the main graft, the allogenic group had the lowest risk of wound dehiscence (odds ratio=0.106, P =0.006). Though the external connection group had a higher risk of wound dehiscence than the internal connection group (odds ratio=2.381), the difference was not significant (P =0.100).

Conclusion:

In this study, male gender and main graft have the highest risk of wound dehiscence. To reduce wound dehiscence after GBR, instructions on postoperative care with supplementary procedure for the protection of the wound dehiscence is recommended, especially to male patients. A main graft with a gel base can reduce the risk of wound dehiscence.

Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus

BACKGROUND

Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxillae with implant-supported prostheses. Bone volume is limited by the presence of the maxillary sinus together with loss of alveolar bone height. Sinus lift procedures increase bone volume by augmenting the sinus cavity with autogenous bone or commercially available biomaterials, or both. This is an update of a Cochrane review first published in 2010.

OBJECTIVES

To assess the beneficial or harmful effects of bone augmentation compared to no augmentation when undertaking a sinus lift procedure. Secondly, to compare the benefits and harms of different maxillary sinus lift techniques for dental implant rehabilitation.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 17 January 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 12), MEDLINE via OVID (1946 to 17 January 2014) and EMBASE via OVID (1980 to 17 January 2014). There were no language or date restrictions on the searches of the electronic databases.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants that report the outcome of implant success or failure at least to four months after initial loading.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the risk of bias of the trials, and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed using fixed-effect models as there were either less than four studies or we used Peto odds ratios (ORs) for dichotomous data when there were zero cells in either the treatment or control or both arms and the number of trials was small. The statistical unit of the analysis was the patient.

MAIN RESULTS

Eighteen RCTs out of 64 potentially eligible study reports met the inclusion criteria. They compared undertaking a sinus lift with not doing so, and the use of different sinus lift techniques. There were 650 patients providing data for the outcomes evaluated. Five studies were assessed as low risk of bias, 11 were assessed as high risk of bias, and in two the risk was unclear. Sinus lift versus no sinus lift Four trials of moderate quality (three trials at low and one at high risk of bias) with 102 participants evaluated short implants (5 to 8.5 mm long) as an alternative to sinus lift in bone with residual height between 4 and 9 mm. One year after loading there was insufficient evidence to claim differences between the two procedures for prosthesis failure (OR (Peto) 0.37, 95% confidence interval (CI) 0.05 to 2.68; three trials) or implant failure (OR (Peto) 0.44, 95% CI 0.10 to 1.99; four trials). There was however an increase in complications at treated sites when undertaking the sinus lift (OR (Peto) 4.77, 95% CI 1.79 to 12.71, P value = 0.002; four trials). Different sinus lift techniques Fourteen trials with 548 participants compared different sinus lift techniques. Only three comparisons included more than one trial (two trials for each). These were bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet-rich plasma (PRP). There was insufficient evidence to claim a benefit for any of these techniques for the primary outcomes of prosthesis and implant failure. For the other reported outcomes, in a single study at high risk of bias, only bone gain was greater for the bone graft site than the site without a graft six months after augmentation, however this was not significant at 18 or 30 months.The other comparisons with single studies were rotary versus piezosurgery to open a lateral sinus window, two different bone substitutes, use or not of a membrane to seal the lateral window, one- versus two-stage lateral sinus lift, two-stage granular bone versus one-stage autogenous bone blocks, and crestal versus lateral sinus lift; two trials compared three different crestal sinus lifting techniques: rotatory versus hand malleting (patients preferred rotatory instruments over hand malleting) and hand versus electric malleting. There was no evidence of a benefit for any sinus lift procedure compared to any other for the primary outcomes prosthesis or implant failure.

AUTHORS' CONCLUSIONS

There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 8.5 mm) in reducing prosthesis or implant failure up to one year after loading. However, there are more complications at sites treated with sinus lift procedures. Many trials compared different sinus lift procedures and none of these indicated that one procedure reduced prosthetic or implant failures when compared to the other. Based on low quality evidence, patients may prefer rotary instruments over hand malleting for crestal sinus lift.

Schneiderian membrane detachment using transcrestal hydrodynamic ultrasonic cavitational sinus lift: a human cadaver head study and histologic analysis

PURPOSE

Recent studies have suggested the osteogenic layer of the periosteum at the base of the sinus membrane to play a key role in bone regeneration after sinus lift procedures. Thus, atraumatic detachment of the sinus membrane with an intact periosteum seems mandatory. The present histologic study of fresh human cadaver heads investigated the detachment behavior and histologic integrity of the detached periosteum after application of the transcrestal hydrodynamic ultrasonic cavitational sinus lift (tHUCSL-INTRALIFT).

MATERIALS AND METHODS

A total of 15 sinuses in 8 fresh human cadaver heads were treated using tHUCSL-INTRALIFT. After surgery, they were checked macroscopically for damage to the sinus membrane and then processed for histologic inspection under light microscopy. A total of 150 histologic specimens, randomly selected from the core surgical sites, were investigated using hematoxylin-eosin (HE), Azan, and trichrome staining.

RESULTS

None of the 150 inspected specimens showed any perforation or dissection of the periosteum from the subepithelial connective tissue and respiratory epithelium and were fully detached from the bony antrum floor. The connecting Sharpey fibers revealed to be cleanly separated from the sinus floor in all specimens.

CONCLUSIONS

The results of the present study suggest tHUCSL-INTRALIFT should be used to perform predictable and safe detachment of the periosteum from the bony sinus floor as a prerequisite for undisturbed and successful physiologic subantral bone regeneration.

A prospective, randomized controlled preclinical trial to evaluate different formulations of biphasic calcium phosphate in combination with a hydroxyapatite collagen membrane to reconstruct deficient alveolar ridges

Many patients and clinicians would prefer a synthetic particulate bone replacement graft, but most available alloplastic biomaterials have limited osteogenic potential. An alloplast with increased regenerative capacity would be advantageous for the treatment of localized alveolar ridge defects. This prospective, randomized controlled preclinical trial utilized 6 female foxhounds to analyze the osteogenic impact of different formulations of biphasic calcium phosphate (BCP) in combination with an hydroxyapatite-collagen membrane and their ability to reconstruct deficient alveolar ridges for future implant placement. The grafted sites were allowed to heal 3 months, and then trephine biopsies were obtained to perform light microscopic and histomorphometric analyses. All treated sites healed well with no early membrane exposure or adverse soft tissue responses during the healing period. The grafted sites exhibited greater radiopacity than the surrounding native bone with BCP particles seen as radiopaque granules. The graft particles appeared to be well-integrated and no areas of loose particles were observed. Histologic evaluation demonstrated BCP particles embedded in woven bone with dense connective tissue/marrow space. New bone growth was observed around the graft particles as well as within the structure of the graft particulate. There was intimate contact between the graft particles and newly formed bone, and graft particles were bridged by the newly formed bone in all biopsies from the tested groups. The present study results support the potential of these BCP graft particulates to stimulate new bone formation. Clinical studies are recommended to confirm these preclinical findings.

Direct vs. indirect sinus lift procedure: A comparison

BACKGROUND

There are different techniques for the sinus augmentation; the factors that contribute to the survival rate of sinus augmentation and dental implant placement are still the subject of discussion. So we compare the two different ways of sinus floor elevation: a) Lateral antrostomy as a one or two step procedure as direct method. b) Osteotome technique with a crestal approach as indirect method.

MATERIALS AND METHODS

A total of twenty partially edentulous patients in maxillary posterior region who opted for implant retained prosthesis but had a low sinus and deficient alveolar ridge within the age group of 20-55 years were taken up, 25 implants were placed in combination with bone grafting material for sinus augmentation. The final bone height was measured from Orthopantomogram. Post-operative Clinical Evaluation was based on pain, gingival inflammation status, stability, swelling and bone height. Statistical analysis was done by using Statistical Package for Social Sciences (version 15.0) (SPSS Inc., Chicago, IL, USA).

RESULTS

The gain in bone height was significantly greater in direct procedure through lateral antrostomy (mean 8.5 mm) than in indirect method through crestal approach by osteotome technique (mean 4.4 mm).

CONCLUSIONS

Osteotome technique can be recommended when more than 6 mm of residual bone height is present and an increase of 3-4 mm is expected. In case of more advanced resorption direct method through lateral antrostomy has to be performed. Both sinus elevation techniques did not seem to affect the implant success rate.

Repair of critical-size bone defects using bone marrow stromal cells: a histomorphometric study in rabbit calvaria. Part I: use of fresh bone marrow or bone marrow mononuclear fraction

OBJECTIVES

The aim of this study was to compare the bone healing observed after the use of (1) a scaffold enriched with fresh bone marrow, (2) a scaffold enriched with bone marrow mononuclear fraction, and (3) a scaffold alone.

MATERIAL AND METHODS

Twenty one rabbits were randomly divided into three groups of six animals and 1 group of 3 animals. Bilateral 12-mm diameter defects were created in the animals' parietal bones. In Control Group, the defects were filled with a xenograft alone (n = 6); in Group 1, with a xenograft enriched with fresh bone marrow (n = 6); in Group 2, with a xenograft enriched with bone marrow mononuclear fraction (n = 6) and in Unfilled Group, nothing was grafted (n = 3). In Groups 1, 2, and Control, one of the calvarial defects was randomly covered with a barrier membrane. The rabbits were sacrificed 8 weeks after surgery, and their parietal bones were harvested and analyzed histomorphometrically.

RESULTS

The histomorphometric analysis showed no difference between Group 1 and the Control Group regarding non-vital mineralized tissue area, but Group 2 showed a statistically significant higher percentage than the Control Group (P < 0.05) for both situations, with membrane (21.24 ± 3.78% and 13.52 ± 3.00%, respectively) and without membrane (20.91 ± 2.01% and 13.08 ± 1.72%, respectively). Group 2 showed the highest percentage of vital mineralized tissue area, followed by Group 1 and the Control Group (P < 0.05) for both situations, with membrane (28.17 ± 3.19%; 21.14 ± 7.38% and 13.06 ± 5.24%, respectively) and without membrane (21.13 ± 0.55%; 12.45 ± 6.34% and 6.56 ± 1.20%, respectively). Group 2 showed the lowest percentage of non-mineralized tissue area, followed by Group 1 and Control Group (P < 0.05) for both situations, with membrane (50.59 ± 6.64%; 58.75 ± 7.14% and 73.41 ± 6.87%, respectively) and without membrane (57.97 ± 1.91%; 71.74 ± 6.63% and 80.37 ± 2.67%, respectively). The sides in which the defects were covered with the barrier membrane showed better bone healing compared with the uncovered sides, in all groups (intragroup comparison, P < 0.05). The Unfilled Group specimens showed no bone formation.

CONCLUSIONS

Both methods using bone marrow stromal cells contributed to enhancing bone healing, especially that using the bone marrow mononuclear fraction. The use of a barrier membrane seemed to have a synergistic effect.

Xenograft enriched with autologous bone marrow in inlay reconstructions: a tomographic and histomorphometric study in rabbit calvaria

Objective. The aim of this study was to evaluate the bone healing after the usage of a scaffold enriched with bone marrow. Study Design. Ten rabbits were divided into 2 groups of 5 animals. Bilateral 12 mm diameter defects were created in the parietal bones. In control group Bio-Oss were inserted in both defects and, in experimental group, Bio-Oss enriched with autologous bone marrow were inserted in both defects. In these two groups, one of the calvarial defects was covered with Bio-Gide. The rabbits were sacrified 8 weeks after surgery and both CT and histomorphometric analysis were done. Results. The CT showed a lower remaining defect area in the experimental group covered with Bio-Gide when compared with control group, with and without Bio-Gide. The histomorphometrics showed no difference between groups regarding the non-vital mineralized tissue area. For vital mineralized tissue area, the experimental group covered with Bio-Gide obtained a higher percentage area when compared with control group, with and without Bio-Gide. For non-mineralized tissue area, the experimental group covered with Bio-Gide obtained a lower percentage area when compared with control group, with and without Bio-Gide. Conclusion. Both autologous bone marrow and membrane can contribute to the enhancement of bone healing.

Radiographic and histologic evaluation of platelet-rich plasma and bovine-derived xenograft combination in bilateral sinus augmentation procedure

There is currently a great interest regarding the use of platelet-rich plasma (PRP) in combination with various bone graft materials in sinus lift procedures. The purpose of this study was to assess and compare the radiographic and histological results of sinus augmentation procedures following treatment with PRP/bovine-derived xenograft (BDX) vs. BDX/collagen membrane. Using a split mouth design, 10 patients, with ≤5 mm of residual alveolar bone in the vertical direction, were treated with PRP/BDX or BDX/collagen membrane. At 8 months after surgery, both graft materials led to a satisfactory increase in vertical dimensions of bone. Bone biopsies were taken from the augmented sites during the implant placement. Histological analysis demonstrated that majority of the trabecula contained orderly layered lamellar bone in the PRP/BDX group, whereas mainly woven bone with a haphazard arrangement of collagen fibers were noticed in the BDX /collagen membrane group. It can be concluded that both combinations resulted with a satisfactory bone height, but more prominent and mature bone formation was observed at sites treated with PRP/BDX.

The effect of bovine bone graft with or without platelet-rich plasma on maxillary sinus floor augmentation

PURPOSE

The purpose of this study was to compare Unilab Surgibone (USB) (Mississauga, Ontario, Canada), a bone xenograft (bovine), with platelet-rich plasma (PRP) and USB without PRP to augment the human maxillary sinus in preparation to receive dental implants.

PATIENTS AND METHODS

Patients who had bilateral pneumatized maxillary sinuses were included. Sinuses on one side were augmented with the USB-PRP combination and formed the study group, whereas the opposite-side sinuses were augmented with USB alone and served as controls. Bone biopsy specimens were taken during implant placement at 6.8 ± 0.9 months after maxillary sinus floor augmentation. Resonance frequency analysis measurements were performed at implant placement (first control) and before the prosthetic stage (second control), at 6.5 ± 0.7 months after implant surgery.

RESULTS

There were 10 patients (7 men and 3 women; mean age, 53.7 ± 0.8 years). Integration between new bone and residual grafts was histologically observed in all samples. The volumes of soft tissue were 59.9% ± 7.5% and 57.8% ± 4.4% in the control and study groups, respectively; residual graft, 21.9% ± 6.6% and 23.6% ± 5.9%, respectively; new bone, 15.8% ± 4.8% and 16.0% ± 3.8%, respectively; and trabecular bone, 64.7% ± 22.5% and 69.1% ± 18.6%, respectively. A positive correlation was found between new bone volume and trabecular bone volume (P = .0001). The mean Implant Stability Quotient (ISQ) values were 71.7 ± 4.9 and 70.3 ± 5.7 in the control and study groups, respectively, at first control and 75.4 ± 6.4 and 74.4 ± 6.4, respectively, at second control. The mean ISQ values at second control in both groups were significantly higher than at first control (P = .043 and P = .028, respectively). No statistically significant differences were observed between groups (P > .05).

CONCLUSION

The combination of USB and PRP does not have any effect on new bone formation and implant stabilization.

Case series of maxillary sinus augmentation with biphasic calcium phosphate: a clinical and radiographic study

Purpose

The aim of this study was to evaluate 3.5 years-cumulative survival rate of implants placed on augmented sinus using Osteon, a bone graft material, and to assess the height of the grafted material through radiographic evaluation.

Methods

Twenty patients were treated with maxillary sinus augmentation and 45 implant fixtures were installed simultaneously or after 6 months healing period. The height of the augmented sinus and the loss of marginal bone were measured by panoramic and intraoral radiographs immediately after augmentation and up to 42 months (mean, 19.4 months) subsequently. Changes in the height of the sinus graft material were calculated radiographically.

Results

The cumulative survival rate was 95.56% in all 45 implants. Additionally, normal healing process without any complication was observed in all patients. The original sinus height was mean 4.3 mm and the augmented sinus height was mean 13.4 mm after the surgery. The mean marginal bone loss till 42 months was 0.52±0.56 mm. The reduced height of Osteon was 0.83±0.38 mm and it did not show significant correlation with the follow up periods (P=0.102). There were no statistically significant differences in reduced height of Osteon according to the simultaneous/delayed implantation (P=0.299) and particle size of Osteon (P=0.644).

Conclusions

It can be suggested that Osteon may have predictable result when it was used as a grafting material for sinus floor augmentation.

Clinical and histologic outcomes after the use of a novel allograft for maxillary sinus augmentation: a case series

PURPOSE

To document the clinical and histologic outcomes of sinus augmentation using a novel allogenic bone substitute as a sole grafting material.

MATERIALS

Patients in need of sinus augmentation before implant placement were recruited for this study. Sinus augmentation procedures were performed following a lateral approach, using a freeze-dried allograft as the only grafting material. Patients were followed up postoperatively for 6 months. Plaque score, wound healing, and patient discomfort were recorded at each follow-up visit. Implants were placed between 6 and 7 months after sinus augmentation and restored 6 months later. Bone core biopsy specimens were harvested at the time of implant placement and processed for histologic and histomorphometrical analysis. Vital bone, remaining allograft (RA) particles, and nonmineralized tissue percentages were assessed on each sample. Results were expressed as mean percentages with SD.

RESULTS

Of the 23 sinus patients, 20 patients underwent sinus augmentation surgery. All patients had satisfactory postoperative healing in the absence of complications. A total of 39 implants were placed. One implant failed and was replaced 3 months later. Histologic analysis revealed the presence of well-organized lamellar bone, in direct contact with RA particles. Mean vital bone was 23.02 +/- 19.11%, mean RA was 22.25 +/- 20.30%, and average nonmineralized tissue was 54.73 +/- 13.51%.

CONCLUSION

Clinical and histologic findings support the suitability of an allograft consisting of a combination of cortical and cancellous chips for sinus augmentation procedures.

Comparison of clinical outcomes of sinus bone graft with simultaneous implant placement: 4-month and 6-month final prosthetic loading

OBJECTIVES

The aim of this study was to compare the survival rate and surrounding tissue condition of sinus bone grafts with simultaneous implant placement between 4-month and 6-month occlusal loading after implantation.

STUDY DESIGN

Twenty-seven patients (61 implants) who were treated with sinus bone grafts (sinus lateral approach) and simultaneous Osstem GS II implant placement from July 2007 to June 2008 were included in this study. Of these patients, 14 (31 implants) were in the 4-month loading group, and 13 (30 implants) were in the 6-month loading group. We investigated the implantation type (submerged or nonsubmerged), sinus membrane perforation, type of prosthesis, opposed tooth type, primary and secondary stability of implants, and crestal bone loss around implant and surrounding tissue conditions.

RESULTS

The amounts of crestal bone-loss at the final recall time (12.56 ± 5.95 mo after loading) of the 4-month and 6-month loading groups were 0.19 ± 0.33 mm and 0.39 ± 0.86 mm, respectively. However, the difference between groups was not statistically significant (P = .211). The width of keratinized mucosa, gingival index, plaque index, and pocket depth of the 4-month and 6-month loading groups were 2.50 ± 1.69 mm and 1.73 ± 1.40 mm (P = .081), 0.72 ± 0.83 and 0.59 ± 0.69 (P = .671), 1.11 ± 0.96 and 0.76 ± 0.79 (P = .226), 3.56 ± 0.98 mm and 3.65 ± 1.06 mm (P = .758), respectively. The primary stabilities of implants in the 4-month and 6-month loading groups were 61.96 ± 12.84 and 56.06 ± 15.55 (P = .120), and the secondary stabilities were 71.85 ± 6.80 and 66.51 ± 11.28 (P = .026), respectively. The secondary stability of the 4-month group was significantly higher than that of the 6-month group. There was no statistical difference (P > .05) between the 4-month and 6-month loading groups regarding the implantation type (submerged or nonsubmerged), sinus membrane perforation, type of prosthesis, or opposed tooth type. In the 4-month and 6-month groups, all of the implants survived until the final recall time.

CONCLUSIONS

For the cases in which the residual bone was >3 mm and primary implant stability could be obtained, we conclude that loading is possible 4 months after the sinus bone graft and simultaneous implant placement.

Diagnosis and treatment of maxillary sinusitis after implant placement

PURPOSE

The purpose of this study was to evaluate the prognosis and treatment of infection of the maxillary sinus associated with dental implants.

METHODS

Oral and radiographic general clinical features of 2 patients who developed maxillary sinusitis after implant placement.

RESULTS

The symptoms of maxillary sinusitis were improved by curettage through the lateral wall of the maxillary sinus, antibiotics, and sinus irrigation after 2 weeks of the operation.

CONCLUSION

It was concluded that acute maxillary sinusitis should be treated with a direct approach to the maxillary sinus via lateral wall opening, regular irrigation in hospital, and antibiotics.

A clinical study on bone formation using a demineralized bone matrix and resorbable membrane

OBJECTIVES

The purpose of this study was to evaluate new bone formation following guided bone regeneration (GBR) using a composite of demineralized cortical and nondemineralized cancellous bone admixed in a poloxamer reverse phase carrier (Orthoblast II) and resorbable collagen membrane (Ossix).

STUDY DESIGN

Fourteen patients (14 specimens) participated in this study from January 2006 to May 2006. In all these 14 patients, bone grafting for the regeneration of dehiscence defects around the implants was required. At the 4- and/or 6-month healing period, a biopsy specimen was obtained by one oral and maxillofacial surgeon. The specimens were fixed, demineralized, embedded, and sectioned by a pathologist, and histomorphometric evaluations were performed using a computer-assisted Visus Image Analysis System.

RESULTS

A high proportion of new bone formation (12.3%-78.7%) was observed during the 4- and/or 6-month healing period. Although histopathologic findings indicated that the grafted materials did not completely resorb, new bone formation and bone remodeling were observed to increase with healing time.

CONCLUSION

It was concluded from this study that the use of GBR consisting of Orthoblast II and Ossix membranes caused favorable bone formation during the 6-month healing period. Additionally, the increase in the woven bone to lamellar bone (LB/WB) ratio and the new bone to residual graft material (NB/GM) ratio observed in this 6-month study also provided evidence of increasing bony remodeling and maturity as well as the continuous resorption of the grafting materials.

Interventions for replacing missing teeth: augmentation procedures of the maxillary sinus

BACKGROUND

Insufficient bone volume is a common problem encountered in the rehabilitation of the edentulous posterior maxillae with implant-supported prostheses. Bone volume is limited by the presence of the maxillary sinus together with loss of alveolar bone height. Sinus lift procedures increase bone volume by augmenting the sinus cavity with autogenous bone and/or commercially available biomaterials.

OBJECTIVES

To determine whether and when augmentation of the maxillary sinus are necessary and which are the most effective augmentation techniques for rehabilitating patients with implant-supported prostheses.

SEARCH STRATEGY

The Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and EMBASE were searched on 7th January 2010. Several dental journals were handsearched. The bibliographies of review articles were checked, and personal references were searched. More than 55 implant manufacturing companies were also contacted.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants reporting the outcome of implant success/failure at least to abutment connection.

DATA COLLECTION AND ANALYSIS

Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted independently and in duplicate. Authors were contacted for any missing information. Results were expressed as random-effects models using mean differences for continuous outcomes and odds ratios for dichotomous outcomes with 95% confidence intervals. The statistical unit of the analysis was the patient.

MAIN RESULTS

Ten RCTs out of 29 met the inclusion criteria. One trial of 15 patients evaluated implants 5 mm long with 6 mm diameter as an alternative to sinus lift in bone with a residual height of 4 to 6 mm. Nine trials with 235 patients compared different sinus lift techniques; of these four trials (114 patients) evaluated the efficacy of platelet-rich plasma (PRP). Due to the variety of techniques evaluated, meta-analysis was only possible of use of PRP for implant failure (two trials) and complications (three trials). No statistically significant difference was observed.

AUTHORS' CONCLUSIONS

Conclusions are based on few small trials, with short follow-up, and judged to be at high risk of bias. Therefore conclusions should be viewed as preliminary and interpreted with great caution. It is still unclear when sinus lift procedures are needed. 5 mm short implants can be successfully loaded in maxillary bone with a residual height of 4 to 6 mm but their long-term prognosis is unknown. Elevating the sinus lining in presence of 1 to 5 mm of residual bone height without the addition of a bone graft may be sufficient to regenerate new bone to allow rehabilitation with implant-supported prostheses. Bone substitutes might be successfully used as replacements for autogenous bone. If the residual alveolar bone height is 3 to 6 mm a crestal approach to lift the sinus lining, to place 8 mm implants may lead to fewer complications than a lateral window approach, to place implants at least 10 mm long. There is no evidence that PRP treatment improves the clinical outcome of sinus lift procedures with autogenous bone or bone substitutes.