Volume changes of autogenous bone after sinus lifting and grafting procedures: A 6-year computerized tomographic follow-up

A Study of Two Novel Techniques for One-stage Closure of Chronic Oroantral Fistula and Sinus Floor Lift

PURPOSE

This study aimed to compare two novel techniques for chronic oroantral fistula (OAF) closure combined with maxillary sinus floor elevation.

MATERIALS AND METHODS

Ten patients who had implant installation needs but suffered from a chronic OAF were enrolled in the study from January 2016 to June 2021. The technique applied involved OAF closure and simultaneous sinus floor elevation by either a transalveolar or lateral window approach. Bone graft material evaluation results, postoperative clinical symptoms and complications were compared between the two groups. Student's t -test and χ 2 test were used to analyze the results.

RESULTS

In this study, 5 patients with a chronic OAF were treated with the transalveolar approach (group I), and 5 were treated with the lateral window approach (group II). The alveolar bone height was significantly higher in group II than in group I ( P ＜0.001). The pain at 1 day ( P =0.018) and 3 days ( P =0.029) postoperatively and facial swelling at 7 days ( P =0.016) postoperatively were obviously greater in group II than in group I. There were no severe complications in either group.

CONCLUSIONS

The techniques combined OAF closure with sinus lifting to reduce surgical frequency and risks. The transalveolar approach resulted in milder postoperative reactions, but the lateral approach could provide more bone volume.

Risk factors and longitudinal regenerative outcomes of sinus membrane perforation during lateral window sinus floor elevation: A retrospective analysis up to 9 years

BACKGROUND

Lateral-window sinus floor elevation (LSFE) is a reliable procedure to reconstruct the posterior maxilla for implant therapy. This retrospective study aimed to investigate risk factors associated with Schneiderian membrane perforation (SMP) occurrence during LSFE and longitudinal regenerative outcomes following LSFE up to 9 years.

METHODS

Patients who had LSFE between 2010 and 2019 were included. All demographic and surgical-related data were retrieved from existing electronic health records. Radiographs were used to evaluate the vertical dimensional changes of ridge and graft materials and the potential anatomic factors of SMP.

RESULTS

A total of 122 LSFE procedures in 99 patients were included in the study. Mean ridge height gain and graft shrinkages were 9.5 ± 3.47 and 1.57 ± 2.85 mm. The influence of the healing period on graft shrinkage showed a positive trend; the longer the healing period, the greater the graft shrinkage (p = 0.09). The pathology in the sinus showed a positive correlation with SMP (p = 0.07). However, other anatomical factors did not negatively impact SMP and subsequent ridge height gain (p > 0.05).

CONCLUSIONS

With inherent limitation, the findings with up to 9 years of follow-up indicate a consistent ridge remodeling lasting for about 3 years after LSFE procedures. SMP or membrane thickening may not significantly affect the ridge gain following LSFE. The healing period had the most significant influence on graft shrinkage, showing that the longer the healing time between LSFE and implant placement, the greater the graft shrinkage.

Long-Term Results after Placing Dental Implants in Patients with Papillon-Lefèvre Syndrome: Results 2.5-20 Years after Implant Insertion

Aim: A retrospective evaluation of patients with Papillon-Lefèvre syndrome (PLS) treated with dental implants to identify factors that may influence treatment outcomes. Methods: All PLS patients with dental implants currently registered at the Department of Periodontology, Goethe-University Frankfurt (20–38 years; mean: 29.6 years), were recruited. Five patients from three families (two pairs of siblings) with a total of 48 dental implants (inserted in different dental institutions) were included with a follow-up time of 2.5–20 years (mean: 10.4 years). Results: Implant failure occurred in three patients (at least 15 implants). Nearly all patients demonstrated peri-implantitis in more or less advanced stages; 60% of patients demonstrated bone loss ≥50% around the implants. Two patients did not follow any supportive therapy. Conclusions: Implants in PLS patients who did not follow any maintenance programme had a high risk of peri-implantitis and implant loss.

Temporal and Permanent Changes Induced by Maxillary Sinus Lifting with Bone Grafts and Maxillary Functional Endoscopic Sinus Surgery in the Voice Characteristics-Systematic Review

Sinus surgery procedures such as sinus lifting with bone grafting or maxillary functional endoscopy surgery (FESS) can present different complications. The aims of this systematic review are to compile the post-operatory complications of sinus elevation with bone grafting and FESS including voice changes, and to elucidate if those changes are either permanent or temporary. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were used, and the literature was exhaustively searched without time restrictions for randomized and non-randomized clinical studies, cohort studies (prospective and retrospective), and clinical case reports with ≥4 cases focused on sinus lift procedures with bone grafts and functional endoscopic maxillary sinus surgery. A total of 435 manuscripts were identified. After reading the abstracts, 101 articles were selected to be read in full. Twenty articles that fulfilled the inclusion criteria were included for analysis. Within the limitations of this systematic review, complications are frequent after sinus lifting with bone grafts and after FEES. Voice parameters are scarcely evaluated after sinus lifting with bone grafts and no voice changes are reported. The voice changes that occur after FESS include a decreased fundamental frequency, increased nasality, and nasalance, all of which are transitory.

Retrospective study on the merits of bone grafts and the influence of implant protrusion length after osteotome sinus elevation surgery

OBJECTIVES

This study aims to evaluate the endo-sinus bone remodeling of dental implants placed via osteotome sinus floor elevation (OSFE) after 6 months and using different implant protrusion lengths and bone grafts through cone beam computed tomography (CBCT).

METHODS

Ninety-six patients with 124 implants were included and assigned into four groups. Group 1: implant protrusion length<4 mm with bone graft; group 2: implant protrusion length>4 mm with bone graft; group 3: implant protrusion length<4 mm without bone graft; group 4: implant protrusion length>4 mm without bone graft. Apical bone gain (ABG), cortical bone gain (CBG), bone density gain (BDG), and marginal bone loss (MBL) were observed and analyzed at baseline and 6 months after implant surgery.

RESULTS

The CBG in grafted groups 1 and 2 was higher than that in non-grafted groups. The ABG and BDG were higher in non-grafted groups 3 and 4 than in grafted groups, and the levels in group 3 were higher than those in group 4. The CBG in grafted group 2 was higher than that in group 1. No significant difference was observed in MBL analysis.

CONCLUSIONS

The BDG of IPL<4 mm implants was higher than IPL>4 mm implant when bone grafts were not applied. No relevance was observed between IPL and CBG. Bone grafts can accelerate endo-sinus bone remodeling by increasing CBG and dissipating the influence of IPL on BDG.

The use of solvent-preserved human and bovine cancellous bone blocks for lateral defect augmentation - an experimental controlled study in vivo

Background

The aim of this study was to compare new bone formation, resorbed bone matrix, and fibrous enclosed residual bone substitute material in laterally augmented alveolar bone defects using allogeneic, pre-treated and cleaned human bone blocks (tested in dogs, therefore considered to be xenogeneic), and pre-treated and cleaned bovine cancellous bone blocks, both with and without a collagen membrane in order to evaluate their augmentative potential.

Methods

Thirty-two critical size horizontal defects were prepared in the mandible of 4 adult foxhound dogs (8 per dog, 4 on each side). After 3 months of healing, the defects were laterally augmented in a split-mouth-design with either human (HXB) or bovine solvent-preserved bone blocks (BXB). Afterwards, defects were randomly covered with a bovine collagenous membrane (HXB + M, BXB + M). After a healing interval of 6 months, percentages of new bone formation, resorbed bone matrix, and fibrous enclosed residual bone substitute material were compared.

Results

Results showed little new bone formation of up to 3.7 % in human bone blocks (HXB 3.7 % ± 10.2, HXB + M 0.3 %± 0.4, BXB, 0.1 % ± 0.8, BXB + M 2.6 % ± 3.2, p = > 0.05). Percentages of fibrous encapsulation were higher in human bone blocks than in bovine bone blocks (HXB 71.2 % ± 8.6, HXB + M 73.71 % ± 10.6, BXB, 60.5 % ± 27.4, BXB + M 52.5 % ± 28.4, p = > 0.05). Resorption rates differed from 44.8 % in bovine bone blocks covered with a membrane to 17.4 % in human bone blocks (HXB 17.4 % ± 7.4, HXB + M 25.9 % ± 10.7, BXB, 38.4 % ± 27.2, BXB + M 44.8 % ± 29.6, p = > 0.05). The use of additional membranes did not significantly affect results.

Conclusions

Within its limitations, results of this study suggest that solvent-preserved xenogenic human and bovine bone blocks are not suitable for lateral bone augmentation in dogs. Furthermore, defect coverage with a membrane does not positively affect the outcome.

[Radiography study on osteotome sinus floor elevation with placed implant simultaneously with no graft augmentation]

OBJECTIVE

To investigate the change of endo-sinus bone height and bone volume in osteotome sinus floor elevation (OSFE) without bone graft but placing implants simultaneously by using cone beam computed tomography (CBCT) and three dimensional analysis, and to find the impacting factors on endo-sinus bone augmentation.

METHODS

OSFE was performed in 38 edentulous patients with missing teeth at posterior maxillary region, and 44 implants were placed and referred for OSFE using no graft materials. CBCT was performed pre-surgery and 9－68 months post-surgery when the patients encountered another implant surgery. The gained bone height at mesial, distal, buccal and palatal sites around the implant in sinus were measured, volumetric measurements of the endo-sinus gained bone volume (ESGBV) in the elevated region were calculated by Mimics software. Univariate analysis and multiple linear regression were performed to investigate the impacting factors on the gained bone height and ESGBV. Marginal bone loss was recorded according to the periapical radiography after implant restoration.

RESULTS

The mean residual bone height (RBH) pre-surgery was (3.41±1.23) mm, the mean protruded length (PL) into sinus of implant post-surgery was (3.41±1.28) mm, the mean endo-sinus gained bone height was (2.44±1.23) mm at distal sites, (2.88±1.20) mm at mesial sites, (2.83±1.22) mm at buccal sites and (2.96±1.16) mm at palatal sites, the mean endo-sinus gained bone height at distal sites was significantly lower than the other three sites (P < 0.05). The average endo-sinus gained bone height was (2.78±1.13) mm. The mean ESGBV was (122.15± 73.27) mm³. Univariate analysis showed the more RBH, the less bone height gained in sinus, which existed at buccal, lingual, mesial and distal sites (P < 0.001), and the more RBH, the smaller ESGBV gained (P=0.012). The ESGBV was significantly higher in the subjects whose bone generation period was more than 24 months than those whose bone generation period less than 24 months (P=0.034). The more PL, the more bone height and ESGBV gained (P=0.008). Multivariate analysis showed after adjusting factors of gender, age, smoking, width of sinus floor, thickness of sinus membrane pre-surgery, diameter and length of the implant, PL and bone generation period was positively correlated with mean endo-sinus gained bone height and ESGBV, while RBH negatively correlated with mean endo-sinus gained bone height. During the follow-up, the mean marginal bone loss was 0 (0－1.41) mm and all the implants loaded successfully.

CONCLUSION

OSFE without bone graft but with placed implant simultaneously can increase endo-sinus gained bone height and ESGBV. RBH, PL and bone generation period are the significant factors impacting endo-sinus bone augmentation.

The comparative evaluation of transcrestal and lateral sinus floor elevation in sites with residual bone height ≤6 mm: A two-year prospective randomized study

OBJECTIVES

To compare clinical and radiographic outcomes between transcrestal sinus floor elevation (TSFE) and lateral sinus floor elevation (LSFE) approaches of simultaneous implant placement in atrophic maxilla.

MATERIALS AND METHODS

Patients with a residual bone height (RBH) ≤6 mm were enrolled and randomly assigned to TSFE and LSFE groups. Patients in both groups simultaneously underwent sinus floor elevation with bovine-derived xenograft and implant placement. Clinical and radiographic results were evaluated immediately after surgery and after 6, 12, 18, and 24 months. The endo-sinus bone gain (ESBG), apical implant bone height (ABH), endo-sinus bone-implant contact rate (EBICR), and crestal bone level (CBL) were assessed using panoramic radiographs.

RESULTS

Forty-one implants (TSFE: 21, LSFE: 20) were placed in cases with a mean RBH of 3.77 ± 1.16 mm. All implants obtained clinical success and satisfactory ESBG at 24 months. No significant differences were found in ESBG and ABH between two groups immediately after surgery, but LSFE group showed significantly higher values than TSFE group thereafter. Grafts in TSFE group reached stability 6 months earlier than that in LSFE group. In both groups, EBICR was almost 100%, and CBL showed no detectable changes.

CONCLUSIONS

LSFE can achieve higher ESBG 2 years after surgery. Otherwise, TSFE could be an alternative to LSFE, when the access for lateral window preparation is limited. Both approaches were highly predictable for RBH ≤6 mm during 24-month observation period for the implants placed simultaneously.

A biodegradable gelatin-based nanostructured sponge with space maintenance to enhance long-term osteogenesis in maxillary sinus augmentation

The search for bone substitutes that are biodegradable, ensure space maintenance, and have osteogenic predictability, is ongoing in the field of sinus augmentation. We thus compared the bone regeneration potential of nanostructured sponges (NS-Sponge) with that of collagen-stabilized inorganic bovine bones (BO-Collagen), gelatin sponges (Gelatin), and blood clots (Cont) in sinus augmentation of rabbits. NS-Sponge was prepared by thermally induced phase separation with porogen leaching techniques. All the materials were non-hemolytic and cytocompatible. The porous and nanofibrous NS-Sponge showed better dimensional stability to support cell growth and osteogenic differentiation. In vivo, the sinus membrane collapsed in Cont and Gelatin, while BO-Collagen and NS-Sponge maintained the elevated height as assessed by come-beam computed tomography. Limited bone regeneration was observed in Cont and Gelatin. In the entire implanted area, histological analysis revealed a higher percentage of new bone area at 4 weeks of BO-Collagen treatment; however, a significantly greater increase in new bone area was observed after 12 weeks of NS-Sponge treatment. The 12-week remnant NS-Sponge material was significantly lower than the 4-week remnant material. Overall, NS-Sponge may be highly recommended for sinus augmentation, as it exhibits numerous advantages, including excellent operability, clear imaging characteristics, space maintenance, biodegradability, and superior osteogenic potential.

Calvarial graft resorption index in the reconstruction of the maxillary sinus in patients with atrophic maxillas: a prospective clinical study

The objective of this study was to assess the resorption index of particulate calvarial grafts in maxillary sinuses of patients undergoing total reconstruction of an atrophic maxilla with residual alveolar bone that was less than, or equal to, 3mm thick. Twenty-one maxillary sinus floor elevations were carried out using particulate calvarial grafts in 11 individuals with totally edentulous maxillas. All patients had computed tomography (CT) before (T0), and 48hours (T1) and six months after surgery (T2). For each CT scan, linear measurements were taken of sections of the anterior, medial, and posterior regions of the maxillary sinus. There was a significant increase in the height of the maxillary sinus floor when T0 was compared with T1 (p=0.001). There was a statistically significant reduction in all maxillary sinus measurements when T1 was compared with T2; the mean height reduction being 2.36mm (16.87%) in the anterior region, 3.53mm (22.47%) in the medial region, and 2.21mm (22.78%) in the posterior region (p=0.001). Mean resorption was 20.7%. Autogenous calvarial bone used alone is an option for graft material in pneumatised maxillary sinuses and in cases where there is limited alveolar bone.

Effect of amount of biomaterial used for maxillary sinus lift on volume maintenance of grafts

Background

Regardless of the kind of biomaterial used for the graft, it is clear that, over time, the graft undergoes dimensional changes that could influence the final bone volume obtained, which could alter the stability of the installed implants. The aim of the present study was to compared and correlated the graft behavior with the amount (in grams) of xenogeneic and alloplastic biomaterials used in grafts for maxillary sinus lift.

Material and Methods

This retrospective cohort study used 148 CBCT images of 74 grafts from 68 maxillary sinuses lift patients in a university, post-graduate clinic. The weights of biomaterials, categorized in intervals according to amount used, were correlated with the graft volumes at V1 (10 days) and V2 (180 days). Kruskal-Wallis test was used to evaluate the possible bias effect of weight on graft maintenance.

Results

Mean weights of biomaterials used were: Bio-Oss Small® (1.58g); Bio-Oss Large® (1.35g); Endobon® (0.72g); BoneCeramic®+Emdogaim® (0.96g); Cerasorb® (1.13g) and Osteogen® (2.70g). No significant differences (p>0.05). Were found for the influence of these mean amounts in graft maintenance: Bio-Oss Small® (18); Bio-Oss Large® (10); Endobon® (17); BoneCeramic®+Emdogaim® (10); Cerasorb® (11); and Osteogen® (08) at V1 and V2. However, when biomaterials were categorized by intervals, all Cerasorb® interval groups showed statistically significant differences (p<0.001) in graft volume at V2.

Conclusions

The amounts of the biomaterials used could influence the final volume; depending on the biomaterial characteristics. Implant installation was possible with all studied grafts, although graft volume shrinkage should be considered when selecting biomaterial for sinus lift.

Key words:Biocompatible materials; cone beam computed tomography; maxillary sinus; hydroxyapatites.

Distal Displacement of Maxillary Sinus Anterior Wall Versus Conventional Sinus Lift with Lateral Access: A 3-Year Retrospective Computerized Tomography Study

Background: The present study is designed to compare the outcomes of two sinus augmentation procedures: distal displacement of the anterior wall versus standard sinus lifting and grafting with a lateral window approach. Methods: In the displacement group, a localized surgical fracture of the sinus floor achieved through an electromagnetic device results in the distal displacement of the anterior wall. In the filling group, sinus lifting (with lateral access) and grafting with particulate xenogeneic bone substitute was performed. Bone volume beneath the maxillary sinus was investigated with computerized tomography after baseline and postoperative data superimposition. Clinical and radiological outcomes over three years had been evaluated. Results: Forty-three dental implants were selected. The two sinus lift procedures significantly increased the bone volume (p-value ≤ 0.0017) in the displacement group from 1.17 ± 0.34 to 1.53 ± 0.39 cc, with a final bone gain of +0.36 ± 0.17 cc, and in the filling group from 1.24 ± 0.41 to 1.94 ± 0.68 cc, with a bone augmentation of +0.71 ± 0.31 cc. No events of dental implant bulging into the maxillary sinus occurred. Two implants failed early on in the filling group, attesting the 3-year survival rate of 92.6% (CI95%: 82.7–100%). Marginal bone loss at the distal aspect was 1.66 ± 0.72 and 1.25 ± 0.78 mm, respectively, for the displacement and filling groups, with a significant difference (p-value = 0.0497). Conclusion: Results showed a significant and effective bone gain around dental implants at a 3-year survey for both sinus augmented by backward displacement of the anterior wall (+34%) and sinus lifting and grafting with a lateral window approach (+57%).

Sequential healing of the elevated sinus floor with different size of antrostomy: a histomorphometric study in rabbits

PURPOSE

To study the influence of the access window dimensions on the healing at the antrostomy and within the augmented maxillary sinus.

MATERIAL AND METHODS

A maxillary sinus augmentation was performed in twenty-four albino New Zealand rabbits. Antrostomies of 3 × 6 mm (small) or 5 × 6 mm (large) in dimensions were randomly prepared in each animal. A collagenated cortico-cancellous porcine bone was used to fill the elevated region, and an equine collagen membrane was placed on the antrostomies. Three different groups were formed, based on the time of euthanasia, i.e., 2, 4, and 8 weeks from surgery.

RESULTS

No relevant changes of the height of the augmented sinus were detected over time. Mineralized bone increased between 2 and 4 weeks of healing while remained stable between 4 and 8 weeks. The highest amounts of new bone were found close to the sinus bone walls. No antrostomies were found healed with an even layer of corticalized bone, while large amounts of connective tissue were occupying the antrostomy in both groups.

CONCLUSION

Antrostomies of different dimensions resulted in similar outcome in bone formation both in the antrostomy regions and within the elevated sinus.

Grafted bone remodeling following transcrestal sinus floor elevation: A cone-beam computed tomography study

Background

Transcrestal sinus floor elevation is a reliable procedure when additional bone height is needed for maxillary implant placement. However, the grafted bone undergoes remodeling and the dimensional stability of grafted bone height may be affected by several clinical factors, including graft material, sinus anatomy and the morphology of grafted space.

Methods

This retrospective study examined patients who had undergone transcrestal sinus floor elevation with synthetic biphasic calcium phosphate and single implant placement. The reduction of sinus graft height (GHR) after 6–8 months healing period was measured with cone-beam computed tomography (CBCT) images. Correlating factors, including vertical amount of implant protrusion (IP), sinus width, and the morphology of grafted space were analyzed by Spearman's correlation test.

Results

A total of 25 implant sites were analyzed. The mean GHR was 0.57 ± 0.49 mm, which was positively correlated with IP, vertical elevation height (VEH), and the ratio of vertical to horizontal elevation of the grafted space. However, GHR was not correlated with sinus width and mesial-distal or buccal-palatal width of the grafted space.

Conclusions

Synthetic biphasic calcium phosphate used in transcrestal sinus floor elevation underwent shrinkages and graft remodeling. Grafted height reduction was associated with IP, VEH, and the ratio of vertical to horizontal elevation of the grafted space.

Histologic, Histomorphometric, and Clinical Analysis of the Effects of Growth Factors in a Fibrin Network Used in Maxillary Sinus Augmentation

This randomized controlled clinical trial evaluated the effect of mineralized plasmatic matrix (MPM), comprised of synthetic graft and platelet concentrates, on new bone formation and volume stability over time in maxillary sinus lifting (MSL). Unilateral MSL was performed in 20 patients with either beta-tricalcium phosphate (β-TCP) or MPM grafts (10 sinuses each). Six months postsurgery, specimens were obtained with a trephine bur prior to implant placement in 39 cases. Volumetric changes in sinus augmentation were analyzed between 1 week (T-I) and 6 months (T-II) postsurgery. Histomorphometric and histological analyses of biopsy samples revealed mean new bone percentages of 35.40% ± 9.09% and 26.92% ± 7.26% and residual graft particle areas of 23.13% ± 6.16% and 32.25% ± 8.48% in the MPM and β-TCP groups, respectively (p < 0.05). The mean soft-tissue areas in the MPM and β-TCP groups were 41.48% ± 8.41% and 40.83% ± 8.86%, respectively (p > 0.05). Graft reductions between baseline and 6-months postprocedure in the β-TCP and MPM groups were 17.12% ± 13.55% and 14.41% ± 12.87%, respectively, with significant graft volume reduction observed in both groups (p < 0.05) while there is no significant difference between MPM and β-TCP groups (p > 0.05). Thus, MPM, representing growth factors in a fibrin network, increases new bone formation and has acceptable volume stability in MSL procedures

Influence of the use of autogenous bone particles to close the access window after maxillary sinus floor augmentation: an experimental study in rabbits

AIM

To study the influence on the healing of the placement of particulate autogenous bone in the antrostomy and in the subjacent region after maxillary sinus elevation.

MATERIAL AND METHODS

Sixteen New Zealand rabbits were undergone to bilateral maxillary sinus floor augmentation with 4 × 4 mm antrostomy dimension. The sinus mucosa was elevated, and the space obtained was filled with xenograft. In the test site (treated sites), autogenous bone was harvested from the tibia and was placed either in the antrostomy and the subjacent region while the control site was left untreated. Antrostomy was covered bilaterally with collagen membranes. Animals were euthanized after 1 and 8 weeks of healing, with 8 rabbits in each group. Histomorphometric evaluations were done. The Wilcoxon test is used for statistical analysis, for a 5% statistical significance.

RESULTS

After 1 week of healing, the new bone proportion in the antrostomy was 7.7 ± 11.2% and 6.1 ± 6.4% in the treated and untreated sites, respectively. In the subjacent region (close-to-window region), hardly any new bone was assessed. In the elevated region, 2.7-2.8% of total new bone was found in both sites. In the antrostomy region, after 8 weeks of healing, 35.5 ± 20.9% of new bone in the treated sites, and 28.6 ± 24.1% in the untreated sites was observed (p = 0.499). In the close-to-window region, the respective proportions were 25.8 ± 16.1% and 17.6 ± 16.3% (p = 0.018). In the elevated region, the total new bone reached fractions of 27.9 ± 12.9% and 23.6 ± 15.2% in the treated and untreated sites, respectively (p = 0.128).

CONCLUSIONS

The placement of autogenous bone in the antrostomy and the subjacent region after maxillary sinus elevation, slightly enhanced bone formation compared with sites only grafted with xenograft. Though, only the subjacent close-to-window region showed a statistical significance at 8 weeks of healing. Despite the limitations of the present study, due to its preclinical nature, findings should be extrapolated to humans with caution.

Bone Reconstruction Planning Using Computer Technology for Surgical Management of Severe Maxillomandibular Atrophy

Digital imaging technology and refined software programs have significantly improved a clinician's ability to assess and evaluate anatomic structures and quantify both defect size and required graft volume. This article summarizes the computed tomography-based technology used in these applications to illustrate their current use as exemplified by computer-assisted planning and treatment of severe maxillofacial atrophy treated using both interpositional and mesh-onlay grafting methodology.

Dental implants placed in resorbed alveolar ridges reconstructed with iliac crest autogenous onlay grafts: A 26-year median follow-up retrospective study

PURPOSE

To evaluate the long-term outcome of dental implants placed with a staged procedure in resorbed alveolar ridges reconstructed with iliac crest autogenous onlay grafts.

MATERIALS AND METHODS

All consecutive patients treated with iliac crest onlay bone grafts and dental implants were retrospectively evaluated. During the appointment, clinical and radiological examinations were conducted to assess implant survival. A survived implant was defined as an implant still stable and in function at the follow-up visit. Implant survival was estimated at the implant level using Kaplan-Meier analyses. The cumulative survival rate was estimated using a life-table analysis. Subgroup analyses were performed for age, position, and type of retention using the log-rank test. A p-value of <0.05 was considered statistically significant.

RESULTS

The cohort consisted of 21 female subjects receiving a total of 140 rough-surface titanium implants. Of them, 128 survived and 12 failed, yielding a cumulative survival rate of 91.1% over a median survival time of 312 months. Implants supporting cement-retained prostheses exhibithed lower survival rate compared to screw-retained restorations (p = 0.001).

CONCLUSION

Implants placed in bone augmented with iliac crest onlay grafts showed high long-term survival rates. Cement-retained restorations were more prone to develop implant failures.

Association of Smoking Habits and Height of Residual Bone on Implant Survival and Success Rate in Lateral Sinus Lift: A Retrospective Study

The primary aim was to evaluate the association of patient-related factors, biomaterials, and implant characteristics on complications' rate of sinus graft surgery and on implant survival rate in grafted sinus. Secondary aims were to measure bone remodeling around implants and patient satisfaction. A retrospective cohort study was designed. Patients who had computerized tomography (CT) before sinus surgery (T0), orthopantomography after implant surgery (T1) and at follow-up (T2), were included. Specific forms were used to collect clinical data. Radiographic measures were: height of residual bone before sinus surgery measured on CT (T0) and apical and marginal bone levels around implants measured on orthopantomography at T1 and T2. Forty-three lateral sinus lifts were performed. Three grafts failed before implant insertion. Out of 83 implants inserted in 29 patients, a total of 19 failed. Mean follow-up (T2) was 6 ± 1.8 years [4; 11.2 years]. The multilevel models analysis showed no association between complications rate and patient-related factors, biomaterials, and implant characteristics. Smoking (odds ratio [OR]: 8.3; 95% CI 1.46-48.05, P = .0173) and height of residual bone (OR: 0.32 for each mm; 95% CI 0.15-0.68, P = .0034) were associated with implant failure. Bone remodeling between T1 and T2 was -0.8 ± 0.2 mm for apical bone and -0.6 ± 0.3 mm for marginal bone. General therapy satisfaction measured in a visual analogue scale was 8.4 ±1.4. In conclusion, lower height of residual bone before sinus surgery and smoking habits had a negative prognostic effect on survival rate of dental implants placed in grafted sinuses.

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.

Early volumetric changes after vertical augmentation of the atrophic posterior mandible with interpositional block graft versus onlay bone graft: A retrospective radiological study

PURPOSE

The aim of this study was to evaluate volumetric and clinical outcomes of atrophic posterior mandibles treated with inlay or onlay bone grafting techniques.

MATERIALS AND METHODS

In posterior mandibles, alveolar ridges were treated either with interpositional equine cancellous bone block (inlay group) or with onlay autogenous bone block (onlay group). Bone volumes at baseline and at 4 months after surgery were measured by computed tomography.

RESULTS

A total of 20 subjects were enrolled in the present study: 10 in the inlay group and 10 in the onlay group. After surgery, atrophic posterior mandibles showed a mean vertical augmentation height of 6.0 mm in the inlay group and 7.4 mm in the onlay group. No significant differences were recorded between the two groups regarding volume loss of the grafted bone or decrease in vertical bone height of the augmented site (29% and 1.9 mm for the onlay group, and 35% and 1.7 mm for the inlay group) during healing. Two complications (1 wound dehiscence and 1 mandibular fracture) occurred postoperatively in the inlay group; on the other hand, the onlay group had three complications (wound dehiscence). A total of 80 dental implants were placed in augmented areas: 46 in the inlay group with a peri-implant marginal bone loss of 0.8 mm, and 34 in the onlay group with a peri-implant marginal bone loss of 1.3 mm (p = 0.0006).

CONCLUSIONS

Inlay xenogeneic grafts showed volumetric bone remodeling similar to that recorded for onlay autogenous bone. The success of the autogenous onlay blocks (82.4%) appeared to be lower than that registered for the inlay group (93.8%), but the difference was not significant.

Graft-Free Maxillary Sinus Floor Elevation: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aims to investigate survival rates of dental implants placed simultaneously with graft-free maxillary sinus floor elevation (GFSFE). Factors influencing amount of vertical bone gain (VBG), protruded implant length (PIL) in sinus at follow-up (PILf), and peri-implant marginal bone loss (MBL) are also evaluated.

METHODS

Electronic and manual searches for human clinical studies on simultaneous implant placement and GFSFE using the lateral window or transcrestal approach, published in the English language from January 1976 to March 2016, were conducted. The random-effects model and mixed-effect meta-regression were used to analyze weighted mean values of clinical parameters and evaluate factors that influenced amount of VBG.

RESULTS

Of 740 studies, 22 clinical studies were included in this systematic review. A total of 864 implants were placed simultaneously with GFSFE at edentulous sites having mean residual bone height of 5.7 ± 1.7 mm. Mean implant survival rate (ISR) was 97.9% ± 0.02% (range: 93.5% to 100%). Weighted mean MBL was 0.91 ± 0.11 mm, and it was significantly associated with the postoperative follow-up period (r = 0.02; R2 = 43.75%). Weighted mean VBG was 3.8 ± 0.34 mm, and this parameter was affected significantly by surgical approach, implant length, and PIL immediately after surgery (PILi) (r = 2.82, 0.57, 0.80; R2 = 19.10%, 39.27%, 83.92%, respectively). Weighted mean PILf was 1.26 ± 0.33 mm (range: 0.3 to 2.1 mm).

CONCLUSION

Within limitations of the present systematic review, GFSFE with simultaneous implant placement can achieve satisfactory mean ISR of 97.9% ± 0.02%.

SEM-EDX Study of the Degradation Process of Two Xenograft Materials Used in Sinus Lift Procedures

Some studies have demonstrated that in vivo degradation processes are influenced by the material’s physico-chemical properties. The present study compares two hydroxyapatites manufactured on an industrial scale, deproteinized at low and high temperatures, and how physico-chemical properties can influence the mineral degradation process of material performance in bone biopsies retrieved six months after maxillary sinus augmentation. Residual biomaterial particles were examined by field scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to determine the composition and degree of degradation of the bone graft substitute material. According to the EDX analysis, the Ca/P ratio significantly lowered in the residual biomaterial (1.08 ± 0.32) compared to the initial composition (2.22 ± 0.08) for the low-temperature sintered group, which also presented high porosity, low crystallinity, low density, a large surface area, poor stability, and a high resorption rate compared to the high-temperature sintered material. This demonstrates that variations in the physico-chemical properties of bone substitute material clearly influence the degradation process. Further studies are needed to determine whether the resorption of deproteinized bone particles proceeds slowly enough to allow sufficient time for bone maturation to occur.

Volumetric changes of grafted volumes and the Schneiderian membrane after transcrestal and lateral sinus floor elevation procedures: A clinical, pilot study

AIM

To investigate the influence of various surgical techniques for sinus augmentation on the volumetric changes of graft, membrane and the post-operative discomfort.

MATERIALS AND METHODS

Eighteen patients in need of bilateral sinus floor elevation (SFE) were assigned to lateral SFE, transcrestal SFE and intralift procedures. CBCT images taken at baseline, 1 week and 6 weeks were analysed for volumetric changes in graft and Schneiderian membrane. Questionnaires were used to analyse post-op discomfort.

RESULTS

The overall average graft volume obtained after 1 week was 1.87 cm³ (range 0.12-4.72 cm³ ). Volumes decreased after 6 weeks to an overall mean volume of 1.33 cm³ (range 0.10-4.29 cm³ - average decrease of 27.6%). After 6 weeks, the amount of graft volume decreased in every treatment option, ranging from -23.13% for the tSFE, over -24.55% for the lSFE, to -33.71% for the IL. Although all treatment options correspond in an increase in Schneiderian membrane volume, no statistically significant correlation between this increase and loss of graft volume could be obtained for all treatments (p = 0.97).

CONCLUSION

All SFE techniques provided sufficient graft volume for implant treatment. All techniques provoke a partially transient swelling of the Schneiderian membrane. All techniques resulted in a decrease in graft volume after 6 weeks; however, no significant differences were obtained between treatments. Furthermore, no statistical significant correlation between the post-operative swelling of the Schneiderian membrane and reduction in graft volume at 6 weeks could be obtained.

Photoacoustic imaging of dental implants in a porcine jawbone ex vivo

Currently, x-ray-based imaging is used before and after the dental implant treatment, but the ionizing radiation is potentially harmful to patients and operators. Here, we demonstrate ex vivo photoacoustic imaging of a dental implant embedded in a porcine jawbone. By layering biological tissue over the jawbone to mimic a clinical environment, we demonstrate 10 mm deep imaging. Our results show that photoacoustic imaging can provide jawbone anatomical information, the location of an embedded implant fixture, and the thickness of the soft tissue above the jawbone.

Three-Year Clinical and Radiographic Implant Follow-up in Sinus-Lifted Maxilla With Lateral Window Technique

INTRODUCTION

The aim of this study was to evaluate retrospectively the 3-year outcome of implants placed in augmented maxillary sinuses with minimal residual alveolar bone heights (≤3 mm).

MATERIALS AND METHOD

A total of 28 sinus floors were augmented with xenograft, and 58 implants were placed. The outcome measures were implant success based on implant stability and the absence of periimplantitis, and marginal and apical bone resorption on periapical radiograph and prosthesis survival.

RESULTS

Fifty-seven of 58 implants with their prostheses remained functional with a success rate of 98.28%. None of the implants showed any signs of mobility or periimplantitis. Both apical and cervical bone resorption around the implants were highest by the end of the first year.

CONCLUSIONS

The success rate of the implants placed with staged approach in augmented maxillary sinuses with the residual alveolar bone height of ≤3 mm was high in a 3-year term. Bio-Oss is an acceptable substitute autogenous bone and can be used as an augmentation material during the maxillary sinus lift procedure.

Volumetric Stability of Fresh Frozen Bone Blocks in Atrophic Posterior Mandible Augmentation

Fresh frozen bone allografts (FFB) have become an alternative for bone augmentation in the past decades, especially because of the absence of recent reports of disease transmission or immunologic reactions when it is used. The aim of this prospective controlled study is to evaluate volumetric changes of newly created bone following reconstruction of the atrophic posterior mandible. Twenty consecutive patients presenting for reconstruction of posterior mandibular alveolar bone ridge width ≤6.0 mm and/or height ≤6.0 who met all inclusion and exclusion criteria were included. FFB blocks were used. The main outcome variable investigated was bone volume dynamics. Vertical, horizontal, and 3-dimensional bone gain data were measured from computerized tomography scans. The main predictor variable was time evaluated at 3 points: immediately after surgery (T1), at implant placement (T2), and 1 year after functional loading (T3). Secondary outcome parameters evaluated were implant survival, histologic findings, and microtomographic morphometry. The study included 28 hemi-mandibles, 50 FFB bone blocks, and 15 female and 5 male patients (mean age, 51.8 years). Block and implant survival rates were 100% and 96%, respectively, after 31.75 months of follow-up. Vertical and horizontal bone gain at T2 was 5.15 and 6.42 mm, respectively. Volumetric resorption was 31% at T2, followed by an additional 10% reduction at T3. Histologic evaluation showed newly formed vital bone in intimate contact with the remaining FFB. Microtomography revealed 31.8% newly formed bone, 14.5% remaining grafted bone, and 53.7% connective tissue and bone marrow. Thus, FFB blocks may lead to new bone formation and consolidation, with satisfactory volumetric bone maintenance, allowing implant-supported rehabilitation with high success rates.

Autogenous bone grafting for treatment of osseous defect after impacted mandibular third molar extraction: A randomized controlled trial

BACKGROUND

Extraction of impacted mandibular third molar (M3) has been cited as causing osseous defect at the distal aspect of the adjacent second molar (M2).

PURPOSE

This randomized controlled trial was aimed to evaluate the effect of autogenous bone grafting in situ for regeneration of periodontal osseous defect distal to the M2 compared with non-grafting after impacted M3 removal.

MATERIALS AND METHODS

A total of 60 sites in 51 adult patients were enrolled and randomly assigned to the control group or the test group. In both groups, the M3 was extracted using a piezosurgical device, and the distal root surface of M2 was scaled and root planned. In addition, the removed alveolar bone was grinded to particles and grafted to the distal osseous defect of M2 in the test group. The primary outcome variable was the osseous defect depth (ODD), the secondary outcome variables were probing pocket depth (PD) and clinical attachment level (CAL) on the disto-buccal aspect of the M2 during a 12-month follow-up period. Postoperative symptom at 7-day postoperatively and adverse events were also recorded and analyzed.

RESULTS

The patient characteristics were homogeneous between the 2 groups. Six and 12 months after surgery, there were statistically significant bone fill in both groups (P ＜ .01). Moreover, the ODD and CAL in the test group were significantly lower than the control group at every postoperative re-entry (P ＜ .01). The postoperative symptom was more severe in the test group than the control group, but the difference was not significant (P > .05).

CONCLUSIONS

The result of this study demonstrated that scaling and root planning was beneficial to periodontal healing of M2 after impacted M3 extraction. Addition of autogenous bone grafting for the treatment of osseous defects distal to M2 was safe and more effective than periodontal treatment alone. (Registry Number: ChiCTR-IOC-15006561).

Multidisciplinary Management of Candidates for Maxillary Sinus Augmentation by a Surgeon and ENT Specialist

Maxillary sinus augmentation has been shown to be a predictable treatment option for placing dental implants in areas of posterior maxilla with lack of sufficient residual alveolar bone height.¹ The transalveolar (crestal) and the lateral window are the main techniques for the maxillary sinus augmentation with the goal of creating a space beneath the Schneiderian membrane in which to place various grafting materials in order to increase alveolar bone height.

Monophasic ß-TCP vs. biphasic HA/ß-TCP in two-stage sinus floor augmentation procedures - a prospective randomized clinical trial

OBJECTIVES

To compare a monophasic (100% ß-TCP) and a biphasic (60% HA and 40% ß-TCP) bone substitute material (BSM) regarding biocompatibility, osteoconductivity and implant stability using histological, radiological and resonance frequency analysis.

MATERIAL AND METHODS

Sixty-seven sinus floor elevations were performed in 60 patients. One patient group (monophasic bone substitute [MBS], 30 patients, 32 sinuses) was augmented by the use of the monophasic material (Bioresorb^® , Sybron Implant Solutions, Bremen, Germany), while the second group (biphasic bone substitute (BBS), 30 patients, 35 sinuses) received a biphasic material (Maxresorb^® , Botiss Biomaterials, Berlin, Germany). Cone beam CT images were taken immediately after augmentation and prior to implant placement after 6 months. Trephines were harvested, while the implant bed was prepared. Resonance frequency analysis was performed immediately after implant placement and 6 months later. Descriptive analysis was performed on all augmented sinus (n = 67). For statistical comparison of the groups, one sinus of each bilaterally treated patient was randomly excluded, resulting in 30 sinuses grafted with MBS and 30 sinuses grafted with BBS (n = 60).

RESULTS

Histomorphometrical analysis of all sinuses displayed comparable results for both groups regarding new bone matrix (MBS 36.16 ± 19.37%, BBS 38.42 ± 12.61%), residual BSM (MBS 30.26 ± 11.7%, BBS 32.66 ± 12.57%) and non-mineralized tissue (MBS 34.29 ± 18.32%, BBS 28.92 ± 15.04) %) (P > 0.05, respectively). Radiological volume of BBS was significantly more stable (volume loss of 22.2% for MBS, 6.66% for BBS; P < 0.001), and homogeneity of the graft after 6 months was higher for BBS than that for MBS (P < 0.05). Resonance frequency analysis endorsed a higher implant stability quotient for BBS after 6 months than that for MBS (MBS 78.31 ± 5.81, BBS 80.42 ± 6.31; P < 0.05, Mann-Whitney U-test, respectively).

CONCLUSION

Both monophasic and biphasic materials show good biocompatibility and osteoconductivity with satisfactory support on implant stability. BBS remains more stable in terms of volume maintenance and radiological graft homogeneity after a healing period of 6 months.

Influence of Sinus Floor Configuration on Grafted Bone Remodeling After Osteotome Sinus Floor Elevation

BACKGROUND

This study investigates influence of the sinus floor configuration on dimensional stability of grafted bone height after the osteotome sinus grafting procedure.

METHODS

Forty single-tooth dental implants inserted after placement of bioglass and/or allograft into the sinus area using an osteotome technique in 37 patients were evaluated in this retrospective study. Periapical radiographs were taken using the long-cone technique before and after implant placement. Specifically, radiographic measurements of grafted bone height at the mesial and distal side of each implant were taken, and the sinus floor configuration was classified into concave, angle, and flat according to the sinus floor profile at the implant site. Furthermore, the intruding angle, defined as the angle between the implant axis and sinus floor, was measured.

RESULTS

All implants were clinically stable during a mean follow-up period of 39.2 months. Mean initial gain of sinus grafted bone height was 7.0 ± 1.9 mm, and later it was reduced to 4.6 ± 1.9 mm at follow-up (P <0.001). A greater reduction in grafted bone height was revealed in the flat sinus group compared with the concave group (P <0.001). Results from the linear regression showed larger intruding angles were statistically significantly associated with a greater reduction in grafted bone height (r² = 0.55, P <0.001).

CONCLUSION

All bioglass and/or allograft placed in the maxillary sinus after the osteotome technique underwent remodeling and shrinkage; however, the outcome of the procedure was more predictable in sinuses with a concave floor and small implant-intruding angles.

Sinus lift: 3 years follow up comparing autogenous bone block versus autogenous particulated grafts

Background/purpose

The aim of this prospective randomized controlled clinical trial was to compare vertical bone gain and bone resorption after sinus graft procedures performed either with particulate or with autogenous bone block.

Material and methods

Forty-one patients underwent sinus graft procedures with autogenous bone. They were randomly assigned to one group. The first group of 22 patients was treated with autogenous bone block with or without particulated bone, while in the second group of 19 patients sinus floor elevation was performed only with particulated autogenous bone. Linear measurements were recorded before surgery with a computed tomography scan at surgery and at 36 months after sinus lift grafting with a second computed tomography scan. To detect statistical differences Student t test was applied. Differences were considered significant if P values were < 0.05.

Results

There was a statistically significant difference in bone gain for the group treated with bone block grafts.

Conclusion

As a general clinical guideline the clinician should prefer, wherever feasible, en-block bone grafts for sinus floor augmentation procedures.

Accuracy of cone beam computed tomography in following simulated autogenous graft resorption in maxillary sinus augmentation procedure: an ex vivo study

OBJECTIVES:

Maxillary sinus augmentation is a well-documented procedure with long-term success in implant dentistry. Assessing graft volume changes over time is crucial, since resorption remains a major concern. CBCT is commonly employed to assess the quantity and quality of the available bone at the implant receptor site. However, its applicability in following graft volume changes is yet to be determined. The study aimed to assess CBCT accuracy in following simulated graft resorption ex vivo.

METHODS:

4 differently sized autogenous bone blocks harvested from the zygomatic buttress were bilaterally placed in the maxillary sinus of 12 human cadavers. The Accuitomo (J Morita, Kyoto, Japan) CBCT system was employed to scan each one of the 4 grafts in each of the 12 cadavers using identical settings. Gold standard graft measurements were obtained using micro-CT. One independent observer assessed the volume of each graft on CBCT images twice. Intraobserver reliability was assessed using Cohen's kappa and one-sample t-test was used to compare CBCT with micro-CT volumetric measurements.

RESULTS:

The mean micro-CT graft volumes were 97.12 ± 1.4, 197.32 ± 3.4, 361.41 ± 4.2 and 1040.11 ± 3.2 mm³ for Grafts 1-4, respectively, and the mean CBCT volumes of the corresponding grafts were 115.39 ± 7.01, 205.97 ± 9.91, 404.05 ± 16.81 and 1138.04 ± 20.98 mm³. CBCT measurements were statistically significantly different from micro-CT measurements (p = 0.001). Intraobserver reliability was good (r = 0.78).

CONCLUSIONS:

In every case, CBCT overestimated the maxillary graft volume in comparison with micro-CT. However, the measurement differences were limited and might not influence clinical performance.

Late-term healing in an augmented sinus with different ratios of biphasic calcium phosphate: a pilot study using a rabbit sinus model

PURPOSE

The aim of this pilot study was to determine the osteoconductivity and dimensional stability of augmented sinuses using different ratios of biphasic calcium phosphate (BCP) in a rabbit sinus model.

METHODS

Each sinus of New Zealand white rabbits (2.5-3.5 kg) was assigned to one of two groups: BCP with a hydroxyapatite to β-tricalcium phosphate (HA:β-TCP) ratio of 70:30 (group TCP30) and BCP with an HA:β-TCP ratio of 30:70 (group TCP70). After preparing a window in the antral wall of a sinus, the Schneiderian membrane was elevated, and the applicable material was grafted. A fluorochrome calcein green was injected five days before euthanizing the animals at four months post-surgery. The specimens were analyzed histologically, histomorphometrically, and by using micro-computed tomography (micro-CT).

RESULTS

Micro-CT analysis revealed that the total augmented volume and the new bone volume did not differ significantly between the two groups whereas the resorption of materials was greater in the TCP70 group. The trabecular thickness, number, and separation also did not differ significantly between the two groups. Histomorphometrically, the areas of total augmentation, new bone, and residual material, as well as the ratio of new-bone-material contact did not differ significantly between the groups. Histologically, the residual particles were more scattered in the TCP70 group than in the TCP30 group. The fluorescence of the calcein green did not differ notably between the two groups.

CONCLUSIONS

The osteoconductivity and dimensional stability of the two BCPs with different ratios tested in this study were comparable after four months of healing. Therefore, we conclude that both BCPs show promise as a bone substitute for sinus augmentation.

Stability of simultaneously placed dental implants with autologous bone grafts harvested from the iliac crest or intraoral jaw bone

Background

Jaw bone and iliac bone are the most frequently used autologous bone sources for dental implant placement in patients with atrophic alveolar ridges. However, the comparative long-term stability of these two autologous bone grafts have not yet been investigated. The aim of this study was to compare the stability of simultaneously placed dental implants with autologous bone grafts harvested from either the iliac crest or the intraoral jaw bone for severely atrophic alveolar ridges.

Methods

In total, 36 patients (21 men and 15 women) were selected and a retrospective medical record review was performed. We compared the residual increased bone height of the grafted bone, peri-implantitis incidence, radiological density in newly generated bones (HU values), and implant stability using resonance frequency analysis (ISQ values) between the two autologous bone graft groups.

Results

Both autologous bone graft groups (iliac bone and jaw bone) showed favorable clinical results, with similar long-term implant stability and overall implant survival rates. However, the grafted iliac bone exhibited more prompt vertical loss than the jaw bone, in particular, the largest vertical bone reduction was observed within 6 months after the bone graft. In contrast, the jaw bone graft group exhibited a slower vertical bone resorption rate and a lower incidence of peri-implantitis during long-term follow-up than the iliac bone graft group.

Conclusions

These findings demonstrate that simultaneous dental implantation with the autologous intraoral jaw bone graft method may be reliable for the reconstruction of edentulous atrophic alveolar ridges.

Prospective tomographic evaluation of autogenous bone resorption harvested from mandibular ramus in atrophic maxilla

Autogenous bone is considered the criterion standard for grafting procedures of severely resorbed alveolar ridges. However, the rate of autogenous graft resorption remains controversial. The aim of this study was to evaluate the mandibular graft resorption with cone beam computed tomography after 10 and 180 days of augmentation procedures in the atrophic maxilla. Twenty-two patients received 36 autogenous bone grafts harvested from the mandibular ramus. Tomographical evaluations were carried out after 10 (T1) and 180 (T2) days of augmentation procedures to obtain bone grafts area measurements. After 10 days postoperatively (T1), the mean area of bone graft was 81.38 mm (range, 46.33-113.73 mm), whereas, after 180 days postoperatively (T2), the mean area of bone graft was 66.13 mm (range, 33.51-101.93 mm). The mean percentage variation of graft resorption between T1 and T2 was 18.38%. Autogenous bone blocks harvested from the mandibular ramus presented a reduction of 18.38% in the measurement areas after the augmentation procedures in the atrophic maxilla. Therefore, the use of autogenous bone blocks remains as a viable and predictable procedure for the rehabilitation of the atrophic maxillae. Thus, other studies must be carried out to improve the knowledge on the bone graft resorption, which may serve as a basis for the development of more effective strategies for the rehabilitation of patients with an atrophic maxilla.

Reconstruction of alveolar bone defect with autogenous bone particles and osseointegrated implants: Histologic analysis and 10 years monitoring

Maintaining the volume of the alveolar process after extraction can be achieved by immediate implant placement and guided bone regeneration, with or without the use of biomaterials. The authors present a case report with a 10 years follow-up, rehabilitation using osseointegrated implants in the extraction area and maintenance of the volume of the alveolar process with autogenous cortical bone shavings.

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.

A histomorphometric assessment of collagen-stabilized anorganic bovine bone mineral in maxillary sinus augmentation - a randomized controlled trial in sheep

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

Nine sheep underwent bilateral sinus augmentation. Each sinus was randomized to receive either control or test bone graft. Three animals were sacrificed at 8 weeks, and six animals were sacrificed at 16 weeks post-grafting. The 18 sinuses were processed for histomorphometry, which assessed the area fraction of new bone (%NB), residual graft (%RG) and soft tissue components (% STM), as well as graft particle osseointegration (% OI), within three zones equally distributed from the augmented sinus floor.

RESULTS

At week 16, a significant increase in %NB was evident across all three zones in the control group when compared to week 8. A significantly greater %NB was evident in the control group when compared to the test group in zones 2 (P < 0.001) and 3 (P < 0.001). There was a significant increase in %OI in week 16 when compared to week 8 across all three zones in the control group (P < 0.001). %OI in the control group was significantly greater across all three zones when compared to the test group at week 16 (P < 0.001). Zone was found to be a significant main effect (P < 0.001) that was independent of time and treatment with decreasing %OI in distant zones. %RG did not significantly change with time for both groups. There was a significant reduction in %ST in week 16 when compared to week 8 across all three zones in the control group (P < 0.001). %ST in the test group was significantly greater across all zones when compared to the control group at week 16 (P < 0.001).

CONCLUSION

Both groups exhibited very similar histomorphometric measurements in the zones proximal to the resident sinus wall. The % NB and % OI were greatest in the zones proximal to resident bony walls and gradually decreased as the distance from the proximal walls increased. There was greater % NB and % OI in the control group when compared to the test group in the distant zone.

Treatment outcomes of implants performed after regenerative treatment of absorbed alveolar bone due to the severe periodontal disease and endoscopic surgery for maxillary sinus lift without bone grafts

OBJECTIVE

We have developed a regenerative medicine therapy for the alveolar bone and endoscopic surgery for maxillary sinus lift without bone grafts, in patients experiencing severe periodontal disease with significant absorption of the maxillary alveolar bone, in which more than 10 mm of bone thickness in the maxillary bone was attained, with satisfactory results. The objective of this study was to examine the treatment outcomes of implants that were performed after these therapies.

PARTICIPANTS AND METHODS

The participants were 36 patients with severe periodontal disease, who cannot be cured with any other treatments except the extirpation of all teeth. The 36 patients are all patients who underwent regenerative treatment of the alveolar bone through tooth replantation and transplantation of the iliac cancellous bone (the bone marrow) as well as endoscopic surgery for maxillary sinus lift from May 2003 to July 2007 in our clinic. A total of 120 implants were placed in these patients when the replanted teeth fell out because of root resorption, and the success rate was examined.

RESULTS

The success rates of the implants were 16 of 33 (48%) in the group when surveyed less than 2 years after the surgery and 84 of 87 (96.5%) in the group when surveyed more than 2 years after the surgery. A statistically significant difference was found between the 2 groups (Chi-squared test, P < 0.001).

CONCLUSIONS AND CONSIDERATIONS

It was believed that it takes approximately 2 years for the bones in the maxillary sinus floor, augmented through endoscopic surgery for maxillary sinus lift, to attain the thickness and hardness required for implant placement. Therefore, although the implant treatment should be performed later than 2 years after surgery, chewing is possible during this period, with the replanted teeth that were used for regenerative treatment of the alveolar bone. It is believed that this is an extremely effective treatment method to improve the patients' quality of life.

Horizontal-guided Bone Regeneration using a Titanium Mesh and an Equine Bone Graft

AIM

The present work describes a horizontal ridge augmentation in which a titanium mesh was preshaped by adapting it to a stereolithographic model of the patient's jaw that was fabricated from CT scans.

BACKGROUND

Guided bone regeneration (GBR) involves covering the augmentation site with a long-lasting barrier to protect it from the invasion of surrounding soft tissues. Among barriers, titanium meshes may provide a successful outcome, but the intraoperatory time needed to shape them is a disadvantage.

CASE DESCRIPTION

The 54-year-old patient, missing the right mandibular second bicuspid, first molar, and second molar, had her atrophic ridge augmented with a 30:70 mixture of autogenous bone and equine, enzyme-deantigenic collagen-preserved bone substitute. Two conical implants were inserted concomitantly in the second bicuspid and first molar positions, and the site was protected with the preshaped mesh. Four months later, the titanium mesh was retrieved, a bone sample was collected, and histological and histomorphometric analyses were performed. Provisional and definitive prostheses were then delivered, and follow-up controls were performed for up to 24 months.

CONCLUSION

Preshaping the mesh on a model of the patient's mandible shortened the surgical time and enabled faster mesh placement. Two years after surgery, the implants were perfectly functional, and the bone width was stable over time as shown by radiographic controls. Histological analysis of the bone sample showed the heterologous biomaterial to be biocompatible and undergoing advanced remodeling and replacement with newly formed bone.

CLINICAL SIGNIFICANCE

Preshaping a titanium mesh over a stereolithographic model of the patient's jaw allowed for a significant reduction of the intraoperative time and may be therefore, advisable in routine practice.

A retrospective analysis of the relationship between rhinosinusitis and sinus lift dental implantation

INTRODUCTION

Dental implants have been associated with the occurrence of postoperative rhinosinusitis. In some patients, preoperative sinus lifting must be performed to increase the chances of successful implant placement. This retrospective study examines the relationship of dental implants after sinus lifting with the occurrence of postoperative rhinosinusitis.

METHODS

A total of 268 dental implants were inserted in 94 patients (62 Males, 32 Females) between 2011-2013. The ages ranged from 29-71 (in males) and 33-64 (in females). Additionally, bilateral sinus lifing was performed in 51 patients, and unilateral sinus lifting was performed in 43 of the patients. Patients were evaluated for sinus pathology for a period of 5-47 months postoperatively using a satisfaction questionnaire, conventional radiographic examination, and nasal endoscopic examination.

RESULTS

Four of the patients (4.2%) had a complication of postoperative sinusitis and were treated medically. In one patient, the implant was unsuccessful (even after treatment) and was removed. None of the patients needed surgery due to the sinusitis or any associated complications.

CONCLUSION

The risk for postoperative rhinosinusitis was found to be higher in patients who suffer from chronic sinusitis and in cases in which a large amount of graft was utilized for sinus lifting. These predisposing factors need to be considered when evaluating patients for dental implants and sinus lift procedures.