A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation

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.

Platelet-Rich Plasma in Maxillary Sinus Augmentation: Systematic Review

Background: Sinus augmentation can be performed with or without grafting biomaterials, and to date, there is no quality evidence regarding the augmentation of the sinus floor using only platelet concentrates, which can improve the healing period and enhance bone regeneration by stimulating angiogenesis and bone formation. The main objective of this paper was to assess the effect of the sole use of platelet concentrates in sinus augmentation in terms of newly formed bone, augmented bone height, and clinical outcomes and to assess the additional beneficial effects of platelet-rich fibrin (PRF) in combination with other grafting biomaterials. Methods: A systematic review was conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Pooled analyses were performed with the Review Manager software. Results: For sinus elevation only using platelet concentrates, 11 studies met the inclusion criteria and were included for qualitative synthesis. Only one study was a clinical trial, which reported improved outcomes for the allograft group compared to the titanium-PRF (T-PRF) group. A total of 12 studies where PRF was used in addition to grafting biomaterials met eligibility criteria and were included in the review. Results from meta-analyses provided no additional beneficial effects of PRF in sinus augmentation in terms of bone height and percentage of soft tissue area. There was a statistically significant lower percentage of residual bone substitute material in the PRF (+) group compared to the PRF (−) group. The percentage of newly formed bone was slightly higher in the PRF (+) group, but this was not statistically significant. Conclusion: There is no robust evidence to make firm conclusions regarding the beneficial effects of the sole use of platelet concentrates in sinus augmentation. However, studies have shown favorable outcomes regarding implant survival, bone gain, and bone height. The use of PRF with other grafting biomaterials appears to provide no additional beneficial effects in sinus lift procedures, but they may improve the healing period and bone formation. Well-conducted randomized clinical trials (RCTs) are necessary to confirm the available results to provide recommendations for the clinical practice.

Comparison between Micro-Computed Tomography and Cone-Beam Computed Tomography in the Assessment of Bone Quality and a Long-Term Volumetric Study of the Augmented Sinus Grafted with an Albumin Impregnated Allograft

The purpose of our study was to compare micromorphometric data obtained by cone-beam computed-tomography (CBCT) and microcomputed-tomography (micro-CT) of the augmented sinus and to evaluate the long-term stability of the bone gain achieved using BoneAlbumin. Sinus lifts, and after 6-months, healing bone-biopsy and implant placement were carried out. Specimens were analyzed by micro-CT. A total of 16 samples were collected from nine patients (mean age 54.7 ± 6.5 years). Pre-, postoperative, and 3-year control CBCT-data were registered to determine from where the biopsy samples were harvested. Micromorphometric variables were calculated from the micro-CT- and CBCT-data, and their correlation was determined by Spearman's test. The volume of augmented bone was calculated at the time of implant placement and after 3 years. A positive correlation was found between bone-volume fraction, trabecular-separation, open-, and total-porosity, while a negative correlation was found between trabecular-thickness obtained from CBCT- and micro-CT-data (p < 0.05). Mean volumetric reduction of 39.28% (11.88-60.02%) was observed. Correlation of CBCT- and micro-CT-data suggested that micromorphometric analysis of CBCT reconstructions of the augmented sinuses provided reliable information on the microarchitecture of augmented bone. CBCT as a modality might be adequate in the analysis of bone quality in the augmented sinus. At the 3-year, control sinus grafts showed volumetric stability.

Maxillary Sinus Floor Augmentation With or Without Barrier Membrane Coverage of the Lateral Window: a Systematic Review and Meta-Analysis

Objectives

Test the hypothesis of no difference in implant treatment outcomes after maxillary sinus floor augmentation with or without barrier membrane coverage of the lateral window.

Material and Methods

A MEDLINE (PubMed), Embase and Cochrane library search in combination with a hand-search of relevant journals was conducted. Human studies published in English until the 5th of July, 2019 were included. Randomised controlled trials and controlled trials with an observation period of minimum six months were included. Primary outcomes included survival of suprastructures and implants. Secondary outcomes included implant stability quotient, peri-implant marginal bone loss, bone regeneration, patient-reported outcome measures, biologic and mechanical complications.

Results

The electronic search and hand-searching resulted in 1068 entries. Six randomised controlled trials characterised by low to high risk of bias and one controlled trial with high risk of bias fulfilled the inclusion criteria. High implant survival rate was reported with both treatment modalities. Meta-analyses disclosed a mean difference of newly formed bone of 6.4% (confidence interval = 0 to 12.9) and non-mineralised tissue of -1.1% (confidence interval = -2.7 to 0.5), indicating more newly formed bone and diminished non-mineralised with barrier membrane coverage.

Conclusions

There seem to be no statistically significant differences in implant treatment outcomes after maxillary sinus floor augmentation with or without barrier membrane coverage of the lateral window. However, barrier membrane coverage increases percentage of newly formed bone and diminishes proliferation of non-mineralised tissue. Thus, barrier membrane coverage seems to be beneficial and also preventing displacement of the grafting material.

A review of rare complications of maxillary sinus floor augmentation

Maxillary sinus floor augmentation (MSFA) is an essential procedure for implant installation in the posterior maxillary area with vertical alveolar bone deficiency. For the past several decades, MSFA has been refined in terms of surgical methods along with technical progress, accumulation of clinical studies, and development of graft materials and surgical instruments. Although some complications in MSFA are inevitable in clinical situations, management of those complications in MSFA has been well established thanks to many clinicians and researchers. Nevertheless, some rare complications may arise and can result in fatal results. Therefore, clinicians should be well aware of such rare situations and complications associated with MSFA. In this review, the authors present several rare complications regarding MSFA, along with corresponding management strategies through a thorough review of the literature.

Single crowns on tooth root-resected molars: A retrospective multicentric study

STATEMENT OF PROBLEM

Data regarding single restorations on molars treated with root resection and separation are limited.

PURPOSE

The purpose of this retrospective study was to evaluate the clinical success and survival of single crowns on root-resected molars.

MATERIAL AND METHODS

Eighty-six molars were treated with root resection or hemisection, prepared with feather-edge margins and restored with single crowns in 73 patients. The patients were clinically evaluated during regular recall appointments in 2018. Data were analyzed with descriptive statistics.

RESULTS

The mean follow-up time was 88.7 months (standard deviation, 70.6; range, 6 to 284). Six failures were recorded during the observation period, with a cumulative survival rate of 93%.

CONCLUSIONS

In this retrospective evaluation, single crowns on root-resected molars with feather-edge margins had clinical outcomes similar to those reported for single crowns on implants in the molar area. First molars and molars with 2 retained roots showed a better survival rate than second molars.

Long-term effectiveness of maxillary sinus floor augmentation: A systematic review and meta-analysis

AIM

To assess the long-term effectiveness (≥5 years) of maxillary sinus floor augmentation (MSFA) procedures applying the lateral window technique and to determine possible differences in outcome between simultaneous and delayed implant placement, partially and fully edentulous patients and grafting procedures.

MATERIALS AND METHODS

MEDLINE (1950-May 2018), EMBASE (1966-May 2018) and Cochrane Central Register of Controlled Trials (1800-May 2018) were searched. Inclusion criteria were prospective studies with follow-up ≥5 years and a residual bone height ≤6 mm. Outcome measures included implant loss, peri-implant bone level change, suprastructure survival, patient-reported outcome measures and overall complications. Data were pooled and analysed using a random effects model.

RESULTS

Out of 2,873 selected articles, 11 studies fulfilled all inclusion criteria. Meta-analysis revealed a weighted annual implant loss of 0.43% (95% CI: 0.37%-0.49%). Meta-regression analysis did not reveal significant differences in implant loss neither between edentulous and dentate patients nor implants placed simultaneously with or delayed after MSFA, nor implants placed in MSFA using solely autologous bone or bone substitutes. The results of the other outcome measures were favourable, and overall complications were low.

CONCLUSION

MSFA is a reliable procedure in the partially and fully edentulous maxilla for support of dental implants.

Sinus Floor Elevation and Antrostomy Healing: A Histomorphometric Clinical Study in Humans

OBJECTIVES

To compare the histomorphometric outcomes of biopsies collected from the antrostomy and from the alveolar crest of the maxillary sinus after a sinus-lift procedure.

MATERIAL AND METHODS

In 12 volunteers, sinus floor elevation was performed using collagenated corticocancellous porcine bone. Nine months after the surgery, 2 biopsies, 1 from the alveolar crest and 1 from the antrostomy, were collected for histological analysis.

RESULTS

Biopsies from 11 patients were available for histological analyses (n = 11). At the alveolar crest sites, the percentage of mineralized bone was 40.1 ± 14.1%, of bone marrow was 40.1 ± 18.0%, and of the xenograft was 14.7 ± 15.2%. Small amounts of soft tissue were found. At the antrostomy sites, the percentages of mineralized bone, bone marrow, and xenograft were 26.0 ± 10.8%, 23.4 ± 17.0%, and 28.2 ± 15.7%, respectively. Soft tissue was represented by 19.7 ± 19.4%.

CONCLUSION

Higher amounts of mineralized bone and bone marrow were found in the alveolar crest compared with the antrostomy.

Risk factors in lateral window sinus elevation surgery

Maxillary sinus augmentation is the most predictable of the pre-prosthetic surgical procedures. There are, however, known and well-documented complications that can and do occur. The most common are the intraoperative complications of sinus membrane perforation and bleeding, and the postoperative complications of sinus graft infections, sinus infections, and sinusitis. The majority of these complications can be prevented, or their incidence greatly reduced, through a thorough understanding of maxillary sinus anatomy, the multifaceted etiologies of these conditions, and the steps that can be taken to avoid them. This volume of Periodontology 2000 will discuss both the preoperative and intraoperative procedures that will prevent these untoward outcomes and the necessary treatment modalities that will limit their adverse effects.

Short implants (5-8 mm) vs long implants (≥10 mm) with augmentation in atrophic posterior jaws: A meta-analysis of randomised controlled trials

The aim of this systematic review was to compare the survival rate, marginal bone loss changes and complications between short implants (5-8 mm) and long implants (≥10 mm) with a bone-augmented procedure in the posterior jaw. An electronic search of the MEDLINE (PubMed), Embase and Cochrane Library databases through September 2018 was done to identify randomised controlled trials (RCT) assessing short implants and long implants with at least a 1-year follow-up period after loading. A quantitative meta-analysis was conducted on the survival rate, marginal bone loss changes and complications. Ten RCTs met the inclusion criteria. There were no significant differences in the survival rate (RR: 1.01; 95% CI: [0.99, 1.03]; P = .32) and complications (RR: 0.48; 95% CI: [0.20, 1.17]; P = .11) between the two groups. Compared with the long implant group, the short implant group had a lower marginal bone loss change, and the effect measure was significant (mean difference: -0.13; 95% CI: [-0.20, -0.06]; P < .05). This systematic review showed no difference between the survival rates and complications of short implants (5-8 mm) and long implants (≥10 mm). The marginal bone loss changes in short implants are lower than those in long implants.

The etiology of hard- and soft-tissue deficiencies at dental implants: A narrative review

OBJECTIVE

The objective of the present paper was to review factors and conditions that are associated with hard and soft-tissue deficiencies at implant sites.

IMPORTANCE

Hard- and soft-tissue deficiencies at dental implants are common clinical findings. They can lead to complications and compromise implant survival and, hence, may require therapeutic interventions. It is, therefore, important to understand the etiology of hard and soft-tissue deficiencies. Based on this understanding, strategies should be developed to correct hard and soft-tissue deficiencies with the aim of improving clinical outcomes of implant therapy.

FINDINGS

A large number of etiological factors have been identified that may lead to hard and soft-tissue deficiencies. These factors include: 1) systemic diseases and conditions of the patients; 2) systemic medications; 3) processes of tissue healing; 4) tissue turnover and tissue response to clinical interventions; 5) trauma to orofacial structures; 6) local diseases affecting the teeth, the periodontium, the bone and the mucosa; 7) biomechanical factors; 8) tissue morphology and tissue phenotype; and 9) iatrogenic factors. These factors may appear as an isolated cause of hard and soft-tissue defects or may appear in conjunction with other factors.

CONCLUSIONS

Hard- and soft-tissue deficiencies at implant sites may result from a multitude of factors. They encompass natural resorption processes following tooth extraction, trauma, infectious diseases such as periodontitis, peri-implantitis, endodontic infections, growth and development, expansion of the sinus floor, anatomical preconditions, mechanical overload, thin soft tissues, lack of keratinized mucosa, malpositioning of implants, migration of teeth, lifelong growth, and systemic diseases. When more than one factor leading to hard and/or soft-tissue deficiencies appear together, the severity of the resulting condition may increase. Efforts should be made to better identify the relative importance of these etiological factors, and to develop strategies to counteract their negative effects on our patient's wellbeing.

Quantitative and qualitative assessments of intraosseous neurovascular canals in dentate and posteriorly edentulous individuals in lateral maxillary sinus wall

Objective

Knowledge and evaluation of the blood supply within the maxillary sinus before sinus augmentation are vital to avoid surgical complications. The lateral maxilla is supplied by branches of the posterior superior alveolar artery and infraorbital artery forming intraosseous anastomoses (IA) within the bony lateral antral wall. This study was undertaken to (i) measure mean diameter of IA and its distance from the alveolar ridge within dentate and posteriorly edentulous subjects and, (ii) qualitatively display the relationship of IA throughout its course within the lateral maxillary sinus in cone beam computed tomography (CBCT).

Method

Maxillary CBCT images of two-hundred-and-fifty-seven consecutive patients (163 men, 94 women, mean age 42 years) were analyzed. Samples were later divided into dentate (n = 142) and posteriorly edentulous (n = 115) jaws. Using both alveolar ridge and tooth location as reference points, the distance and diameter of IA were assessed.

Result

The IA was seen in 63.7% of all sinuses with 68.2% in dentate and 62.4% in edentulous. Mean distance and diameter of IA across the posterior tooth locations were 17.9 ± 3.0 mm and 1.4 ± 0.5 mm (dentate) and 15.1 ± 3.0 mm and 1.0 ± 0.5 mm (posteriorly edentulous), respectively. In each sample, there were no significant differences in distance-alveolar ridge and no significant correlations in diameter-tooth location. A statistically significant Pearson coefficient correlation between diameter and distance in dentate state was observed (r = −0.6).

Conclusion

This study reveals that dentate maxillary jaws present larger diameters as compared to posteriorly edentulous jaws, although the IA course remains the same. As these canal structures contain neurovascular bundles with diameters that may be large enough to cause clinically substantial complications, a thorough pre-surgical planning is therefore highly advisable.

Cone-beam computed tomography assessment of Schneiderian membranes: Non-infected and infected membranes, and membrane resolution following tooth extraction: A retrospective clinical trial

Background

Cone-beam computed tomography (CBCT) presurgical assessment on the maxillary sinus can reduce the possibility of Schneiderian membrane perforation. This study examined Schneiderian membrane thickness (SMT) and its relationship with neighboring hard tissues for patients with and without membrane thickening. For patients with sinus infections, we evaluated dimensional changes of the SMT post-extraction relative to pre-extraction SMT and residual bone height (RBH).

Methods

CBCT images from 93 patients needing single-tooth implant reconstruction without (n = 83) and with (n = 14) odontogenic infected maxillary sinuses were assessed. SMT, RBH, and lateral wall thickness (LWT) were measured. Causes of extraction, RBH in the infection site, and retrospective post-extraction record of SMT were recorded for the thickened SMT group.

Results

Mean SMT for normal SMT group was 1.13 ± 0.43 mm, RBH was 6.26 ± 2.38 mm; upper and lower LWT was 1.85 ± 0.95 mm, and 3.07 ± 2.26 mm, respectively. RBH and LWT had no significant relationships with SMT. For thickened SMT group, mean values for SMT and RBH prior to extraction were 4.53 ± 2.46 mm and 1.97 ± 1.43 mm, respectively. Pre-extraction SMT had a moderately negative correlation with pre-extraction RBH. SMT resolution in thickened SMT group was observed by 2.80 ± 1.37 months post-extraction; post-extraction SMT was not significantly different from normal SMT group (p = .187).

Conclusions

Within the limitation of the sample size, thickened SMT induced by odontogenic infection subsides about 3 months following tooth extraction, and further sinus lifting implant surgery may be considered.

Maxillary Sinus Augmentation Using Hydraulic Pressure by Lateral Approach and Simultaneous Implant Placement: Clinicoradiographic Study

The purpose of this study was to assess clinically and radiographically efficacy of maxillary sinus augmentation using hydraulic pressure in a lateral approach with immediate implant placement. In a total of 10 patients having less than 4 to 6 mm of subantral bone height, lateral approach sinus membrane elevation procedure was performed using hydraulic pressure with the help of a specialized water lift kit followed by grafting and simultaneous implant placement. Cone beam computed tomography analysis was used to assess the change in subantral bone height from baseline to the 6 months postoperatively. Radiographically, subantral bone height increased from 3.86 ± 1.423 mm at baseline to 15.49 ± 2.73 mm at 6 months postoperatively with a gain of 11.63 + 2.63 mm (P < 0.001). Thus, it is concluded that hydraulic pressure may be efficiently used in lateral sinus augmentation procedures along with simultaneous implant placement.

The etiology of hard- and soft-tissue deficiencies at dental implants: A narrative review

OBJECTIVE

The objective of the present paper was to review factors and conditions that are associated with hard and soft-tissue deficiencies at implant sites.

IMPORTANCE

Hard- and soft-tissue deficiencies at dental implants are common clinical findings. They can lead to complications and compromise implant survival and, hence, may require therapeutic interventions. It is, therefore, important to understand the etiology of hard and soft-tissue deficiencies. Based on this understanding, strategies should be developed to correct hard and soft-tissue deficiencies with the aim of improving clinical outcomes of implant therapy.

FINDINGS

A large number of etiological factors have been identified that may lead to hard and soft-tissue deficiencies. These factors include: 1) systemic diseases and conditions of the patients; 2) systemic medications; 3) processes of tissue healing; 4) tissue turnover and tissue response to clinical interventions; 5) trauma to orofacial structures; 6) local diseases affecting the teeth, the periodontium, the bone and the mucosa; 7) biomechanical factors; 8) tissue morphology and tissue phenotype; and 9) iatrogenic factors. These factors may appear as an isolated cause of hard and soft-tissue defects or may appear in conjunction with other factors.

CONCLUSIONS

Hard- and soft-tissue deficiencies at implant sites may result from a multitude of factors. They encompass natural resorption processes following tooth extraction, trauma, infectious diseases such as periodontitis, peri-implantitis, endodontic infections, growth and development, expansion of the sinus floor, anatomical preconditions, mechanical overload, thin soft tissues, lack of keratinized mucosa, malpositioning of implants, migration of teeth, lifelong growth, and systemic diseases. When more than one factor leading to hard and/or soft-tissue deficiencies appear together, the severity of the resulting condition may increase. Efforts should be made to better identify the relative importance of these etiological factors, and to develop strategies to counteract their negative effects on our patient's wellbeing.

Short implants (≤6 mm) versus longer implants with sinus floor elevation in atrophic posterior maxilla: a systematic review and meta-analysis

OBJECTIVES

To compare the use of short implants (≤6 mm) in atrophic posterior maxilla versus longer implants (≥10 mm) with sinus floor elevation.

DESIGN

A systematic review and meta-analysis based on randomised controlled trials (RCTs).

DATA SOURCES

Electronic searches were conducted in PubMed, Embase and the Cochrane CENTRAL. Retrospective and prospective hand searches were also performed.

ELIGIBILITY CRITERIA

RCTs comparing short implants (≤6 mm) and longer implants (≥10 mm) with sinus floor elevation were included. Outcome measures included implant survival (primary outcome), marginal bone loss (MBL), complications and patient satisfaction.

DATA EXTRACTION AND SYNTHESIS

Risks of bias in and across studies were evaluated. Meta-analysis, subgroup analysis and sensitivity analysis were undertaken. Quality of evidence was assessed according to Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

A total of seven RCTs involving 310 participants were included. No significant difference in survival rate was found for 1-3 years follow-up (RR 1.01, 95% CI 0.97 to 1.04, p=0.74, I²=0%, moderate-quality evidence) or for 3 years or longer follow-up (RR 1.00, 95% CI 0.97 to 1.04, p=0.79, I²=0%, moderate-quality evidence). However, short implants (≤6 mm) showed significantly less MBL in 1-3 years follow-up (MD=-0.13 mm, 95% CI -0.21 to 0.05; p=0.001, I²=87%, low-quality evidence) and in 3 years or longer follow-up (MD=-0.25 mm, 95% CI -0.40 to 0.10; p=0.001, I²=0%, moderate-quality evidence). In addition, short implant (≤6 mm) resulted in fewer postsurgery reaction (RR 0.11, 95% CI 0.14 to 0.31, p<0.001, I²=40%, moderate-quality evidence) and sinus perforation or infection (RR 0.11, 95% CI 0.02 to 0.63, p=0.01, I²=0%, moderate-quality evidence).

CONCLUSIONS

For atrophic posterior maxilla, short implants (≤6 mm) are a promising alternative to sinus floor elevation, with comparable survival rate, less MBL and postsurgery reactions. Additional high-quality studies are needed to evaluate the long-term effectiveness of short implants (≤6 mm).

TRIAL REGISTERATION NUMBER

The protocol has been registered at PROSPERO (CRD42018103531).

Preoperative Maxillary Sinus Imaging and the Outcome of Sinus Floor Augmentation and Dental Implants in Asymptomatic Patients

OBJECTIVES

Preoperative maxillary sinus imaging findings have been suggested to be associated with complications and outcomes of sinus lift and dental implant procedures; nonetheless the evidence is controversial. The aim of this study was to examine the association between preoperative maxillary sinus imaging findings and outcomes of sinus lift and dental implant procedures in asymptomatic patients.

METHODS

We included all patients who underwent maxillary sinus lift and dental implant procedures between 2014 and 2017. Maxillary sinus imaging findings were extracted from pre-procedural dental computed tomography scans, and outcomes of the procedures were assessed.

RESULTS

A total of 145 procedures were included. No sinonasal symptoms were reported preoperatively. In 46% of cases maxillary sinus imaging was abnormal. The most common imaging finding was peripheral mucosal thickening (38%). Sinus floor cyst/polyp was identified in 13% of the cases, of which 47% occupied more than 50% of the sinus volume. Partial or complete opacification of the maxillary sinus was documented in 3% of cases. The sinus ostium and ostiomeatal complex were obstructed in 7% and 1%, respectively. Mucosal perforation was documented in 22% of cases and was inversely related to mucosal thickening (P = 0.011). Other minor post-operative complications did not correlate with radiological findings. Post-surgical sinusitis was not observed in any of the patients regardless of pre-surgical imaging findings.

CONCLUSIONS

Incidental maxillary sinus imaging findings such as mucosal swelling, cysts or polyps, regardless of their severity or size, and maxillary ostial obstruction may not need to be addressed prior to sinus augmentation and dental implant procedures in asymptomatic patients. Patients with complete sinus opacification should be referred to an otolaryngologist prior to surgery. Further controlled trials, in larger cohorts, are needed to corroborate our findings.

The use of 3D models to improve sinus augmentation outcomes - A case report

Sinus augmentation is a predictable procedure that is often required when restoring the posterior maxilla with dental implants. Even with high success rates, careful pre-surgical planning is crucial. A 3D model is a valuable aid for the clinician as it allows for pre-operative simulation, which can reduce surgical time, reduce the risk of intra-operative complications and decrease the potential for error. The aim of this case report is to focus on how such a model is useful when undertaking a sinus augmentation procedure with simultaneous implant placement.

A retrospective study of implants placed following 1-stage or 2-stage maxillary sinus floor augmentation by the lateral window technique performed on residual bone of <4 mm: Results up to 10 years of follow-up

BACKGROUND

The purpose of this study was to compare the survival rates of implants placed following 1-stage or 2-stage maxillary sinus floor augmentation by the lateral window technique (SFALW) performed on residual bone of <4 mm.

METHODS

This study was conducted based on dental records and radiographs obtained from patients who received SFALW from March 2006 to June 2014, being followed up between March 2006 and December 2017. They were divided into 1-stage and 2-stage groups according to the SFALW performed. Statistical analysis was performed to evaluate whether a significant difference existed between 1-stage and 2-stage SFALW in terms of survival rates. Multivariable logistic regression analysis was used to examine the influence of multiple variables on implant failure.

RESULTS

A total of 395 implants (156 implants in the 1-stage group, 239 implants in the 2-stage group) in 167 patients fulfilled the inclusion criteria. Among them, 13 implants (five implants in the 1-stage group, eight implants in the 2-stage group) failed. No significant difference was found in the 10-year cumulative survival rate of implants between the 1-stage group and the 2-stage group (96.8% and 92.5%, respectively, P = 0.656). Multivariable logistic regression analysis demonstrated that implant failure was significantly influenced by implant length and functional time following prosthetic loading.

CONCLUSIONS

The 10-year cumulative survival rates showed no statistically significant difference between implants following 1-stage and 2-stage maxillary SFALW performed on residual bone height of <4 mm.

Evaluation of bone formation following the osteotome sinus floor elevation technique without grafting using cone beam computed tomography: a preliminary study

Background

Osteotome sinus floor elevation (OSFE) is used to increase the bone volume at the site of the maxillary sinus through the transalveolar approach. However, there is uncertainty regarding the necessity of the use of grafting material in order to maintain the space for new bone formation.

Objective

This study aimed to evaluate new bone formation 6 months after osteotome sinus floor elevation without grafting and to evaluate the correlations between residual bone height (RBH), implant protrusion length (IPL), and endo-sinus bone gain (ESBG).

Material and methods

Thirty-one implants (27 patients) from area 14–17 and 24–27 were included in the study. All implants had a history of OSFE without grafting, with cone beam computed tomography (CBCT) taken prior to the surgery. The clinical examination and radiographic examination using CBCT were performed again 6 months after implantation. The RBH, new bone level, ESBG, and IPL were measured. Paired sample t test and Pearson correlation were used to analyze the data.

Results

The average RBH before surgery was 7.14 ± 1.07 mm and 6 months after surgery was 8.95 ± 1.17 mm. There was a significant increase in new bone formation in the 6 months following surgery (p < 0.05). The average ESBG and IPL were 1.8 ± 0.79 mm and 2.02 ± 0.73 mm, respectively. There was a significant positive correlation between the IPL and ESBG (p < 0.05) while there was a negative correlation between RBH and ESBG. This study also demonstrates a decrease in the percentage of bone formation in relation to IPL as the IPL increases. The survival rate of the implant was 100%.

Conclusion

Significant new bone formation can be detected around the implant site 6 months after implantation using OSFE technique without grafting. There is a negative correlation between the RBH and ESBG. While IPL is correlated to ESBG and appears to be the influencing factors of bone formation changes in the maxillary sinus. The preliminary radiographic results suggest that OSFE technique without grafting in combination with optimal IPL can provide sufficient bone height for implant support with a 100% implant survival rate.

Electronic supplementary material

The online version of this article (10.1186/s40729-019-0181-7) contains supplementary material, which is available to authorized users.

Factors influencing long-term survival rates of implants placed simultaneously with lateral maxillary sinus floor augmentation: A 6- to 20-year retrospective study

OBJECTIVES

To evaluate the long-term influence of residual bone height (RBH), sinus membrane perforation and the presence of voids on the survival of implants placed simultaneously with lateral maxillary sinus floor augmentation (MSFA).

MATERIALS AND METHODS

A total of 207 patients (613 implants) who underwent MSFA from 1999 to 2003 and followed up until 2018 were included in this study. RBH and marginal bone loss were assessed using a series of panoramic and periapical radiographs. Cumulative survival rates (CSR) with log-rank tests and hazard ratios of implant failure according to RBH, membrane perforation, and the presence of voids were assessed.

RESULTS

The overall 10-year and 20-year CSRs were 95% (95% CI: 84.95%-85.05%) and 85% (95% CI: 84.95%-85.05%), respectively. CSR was significantly higher for implants with ≥3 mm RBH (n = 260, 92.4%) than those with <3 mm RBH (n = 353, 78.8%) (p = .002). CSR of non-smoking group (n = 312, 90.0%) was higher than that of smoking group (n = 301, 77.1%) (p = .009). There was no significant difference in the hazard ratio of implant failure between the perforated membrane group (n = 245) and the non-perforated group (n = 368). In two out of 11 patients with voids, the inflammation of peri-implantitis progressed into voids, resulting in severe bone resorption.

CONCLUSIONS

The survival of implants placed in <3 mm of RBH, even though it showed a lower CSR, could be considered acceptable. Neither sinus membrane perforation nor the presence of voids appeared to affect implant survival as long as supportive maintenance therapy with proper oral hygiene was provided.

Evaluation of the survival of implant placement simultaneously with sinus augmentation: relationship in maxillary sinus pathologies

OBJECTIVES

This retrospective study aimed to evaluate the effects of existing maxillary sinus pathologies on the survival rates of dental implants placed simultaneously with sinus augmentation.

METHODS

Cone-beam computed tomography images of 88 patients (34 females, 54 males), who underwent sinus augmentation, were retrospectively analyzed and the patients were divided into two groups: with (pathology group) and without pathology (control group). All maxillary sinus pathologies were recorded and categorized into mucosal thickening ( ≥ 3 mm), antral pseudocyst (polypoid mucosal thickening), and complete opacification. Implant survival rates were evaluated after a mean follow-up period of 28.2 ± 9.8 months based on the patient's records and control radiographs.

RESULTS

A total of 115 maxillary sinuses of 88 patients with 168 dental implants were included in the study. Maxillary sinus pathology was detected in 45 patients in the pathology group and 43 patients in the control group. In the pathology group, one implant was lost out of 82 implants during the 27.8 ± 9.5 months follow-up period, while in the control group, 5 implants were lost out of 86 implants during the 25.1 ± 10 months follow-up period. There was no statistically significant difference in the survival rates between the two groups.

CONCLUSIONS

The study concluded that the presence of pathology in the maxillary sinus before surgery does not affect the survival rates of dental implants placed simultaneously with sinus augmentation. The most common pathology noted included mucosal thickening (61.4%), which was detected in 35 patients.

Radiographic outcomes of transcrestal and lateral sinus floor elevation: One-year results of a bi-center, parallel-arm randomized trial

OBJECTIVES

To comparatively evaluate the radiographic outcomes of transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively) when applied concomitantly with implant placement.

MATERIALS AND METHODS

Patients with at least 1 edentulous site with residual bone height (RBH) of 3-6 mm were enrolled in a bi-center, parallel-arm, randomized trial. Both tSFE and lSFE were associated with a bovine-derived xenograft, and implants were inserted concomitantly. In lSFE group, the antrostomy was covered with a resorbable collagen membrane. Marginal bone loss and the maturation of the grafted area were evaluated on periapical radiographs at 6 and 12 months. Twelve-month CT/CBCT was used to assess the effect of grafting procedures circumferentially around the implant. A per-protocol analysis was performed.

RESULTS

The per-protocol study population consisted of 26 patients in the tSFE group and 28 patients in the lSFE group. At 12 months, the median proportion of the implant surface in contact with the peri-implant radiopaque area was 100% in both groups, with no significant inter-group difference. Suboptimal bone-to-implant contact was observed in 13% and 3.6% of tSFE and lSFE cases, respectively. In both groups, marginal bone loss was minimal (≤1 mm) and infrequent, and the radiographic aspect was suggestive of an advanced stage of maturation.

CONCLUSIONS

At sites with RBH of 3-6 mm where implants are placed concomitantly with sinus floor elevation, tSFE and lSFE are both highly predictable in obtaining an implant surface completely embedded in a radiopaque area at 12 months post-surgery. (ClinicalTrials.gov ID: NCT02415946).

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.

Maxillary Sinus Floor Augmentation With Autogenous Bone Graft From the Ascending Mandibular Ramus

PURPOSE

The objective of the present study was to assess patient satisfaction and esthetic implant outcome 10 years after maxillary sinus floor augmentation with autogenous bone graft from the mandibular ramus.

MATERIALS AND METHODS

Maxillary sinus floor augmentation with autogenous bone graft from the mandibular ramus was conducted in 48 consecutive patients from 2002 to 2006. Records and radiographs were retrospectively analyzed. Twenty-four patients including 34 sinus augmentation procedures and 37 implants were evaluated after 10 years. Subjective and professional evaluations of the final periimplant soft tissue, implant crown, and total implant treatment were conducted.

RESULTS

The 10-year survival of suprastructures and implants was 84% and 100%, respectively. The patients were highly satisfied with the esthetic and implant treatment outcome expressed by scores >90 on the visual analog scale. Most implants were characterized by scores of 1 or 2, resulting in a mean pink esthetic score of 9 (maximum 14) and a white esthetic score of 8 (maximum 10).

CONCLUSION

Maxillary sinus floor augmentation with autogenous bone graft is characterized by high long-term implant survival rate and patient satisfaction.

Effects of clinical local factors on thickness and morphology of Schneiderian membrane: A retrospective clinical study

BACKGROUND

It was informed that the thickness of maxillary sinus membrane may be affected by the local and patient-related factors in the literature.

PURPOSE

The aim of this retrospective study is to evaluate factors that may have an influence of the thickness and morphology of the maxillary sinus membrane.

MATERIALS AND METHODS

A total of 414 cone beam computed tomography images of 207 patients were evaluated. Radiographic parameters were evaluated at each maxillary premolar and molar tooth regions. Statistical analysis was performed to assess the association between the maxillary sinus mucosa thickness and morphology. The following factors including gender, periodontal bone loss (PBL), bone density, amount of residual alveolar bone at the edentulous space, vitality of the teeth present, and anatomical relationship between the sinus floor and posterior teeth were evaluated.

RESULTS

The mean thickness of maxillary sinus membrane ranged between 1.47 to 2.92 mm and was significantly thicker in male subjects (P < .05). Positive correlation was detected between the sinus membrane thickness values in each posterior tooth region (P < .05). Thickening of the membrane was noted in 53% of the scans. The most commonly observed morphological change was flat thickening of the membrane (21%). No correlation was found between the evaluated local factors on the thickness and morphology of the maxillary sinus membrane (P > .05).

CONCLUSIONS

Tooth vitality, residual alveolar bone height, and PBL seem to have no effect on the thickness and morphology of the maxillary sinus membrane.

Raising the transcrestal sinus floor in the presence of antral pseudocysts, and in sinus floors with a normal Schneiderian membrane: a retrospective cohort study

In this study we sought to investigate the influence of antral pseudocysts on the raising of the transcrestal sinus floor. We retrospectively studied two groups (test group: those with antral pseudocysts, and controls: those with normal Schneiderian membranes). The crestal approach with simultaneous placement of implants was used for all patients. Cone-beam computed tomography was done before, immediately afterwards, and 4-6 months postoperatively. Nineteen participants (16 male, three female, mean (SD) age 48 (10) years) were enrolled in the test group, and 73 (38 male, 35 female, 44 (11) years) in the control group. Immediately postoperatively the mean (SD) residual bone height was 5.15 (1.34) mm in the test group and 5.36 (1.28) mm in the control group (p = 0.15), and the raised heights of the sinus floor were 4.98 (2.01) mm and 5.47 (2.13) mm (p = 0.35) in the test and control groups, respectively. Four to six months postoperatively the endo-sinus bone gain values were 3.55 (2.46) mm and 4.03 (2.33) mm in the test and control groups, respectively (p = 0.26). All pseudocysts swelled immediately after operation. Four to six months postoperatively, two had remained unchanged, three had increased in volume, six had disappeared, and eight had decreased in volume. The survival rate of implants was 100% for both groups. Within the limitations of this study, transcrestal raising of the sinus floor in the presence of antral pseudocysts may be a viable technique, as they may not influence the clinical effects of raising the sinus floor during healing.

Analysis of Forces Applied During Transalveolar Sinus Lift: A Preliminary Clinical Study

PURPOSE

To introduce a novel modality that enables the measurement of forces applied during a transalveolar sinus floor elevation (tSFE) and to investigate the influence of anatomical and surgical factors on the necessitated force in sinus membrane detachment.

MATERIAL AND METHODS

A new endosinus probe, innovated with a calibrated load cell, was used to test the forces needed to perforate ten maxillary sinuses in 5 human cadavers. The same probe was also used to detach the Schneiderian membrane from the bony floor of 21 human subjects undergoing tSFE.

RESULTS

The force needed to cause membrane perforation in the cadaver sample was on average 3.46 ± 1.04 N. The maximum force applied in vivo to a sinus membrane without perforation was 2.01 ± 0.67 N on average. Regression analysis showed that smoking (P < 0.001), as well as 3.0 mm osteotomy (P < 0.001), was significantly correlated to increased forces during membrane detachment.

CONCLUSIONS

The maximum force needed to detach the membrane was found to be, on average, lower than the membrane breaking load in cadavers. Furthermore, because of smoking and a 3.0-mm osteotomy diameter demonstrating a high association with increased forces during membrane detachment, they may be considered as risk factors of membrane perforation.

Influence of residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone

OBJECTIVE

To evaluate the influence of the posterior residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone.

MATERIAL AND METHODS

Bilateral sinus bone augmentation was performed using anorganic bovine bone in 20 patients with residual bone height <2 mm in at least one site on each side. Trephine samples were removed at the implant insertion site 8 months after the grafting procedure, and histological and histomorphometric analyses were performed to examine the relative amount (%) of new bone, anorganic bovine bone, and soft tissue in the grafted area. Based on cone beam computed tomography evaluation, the sites of implant insertion were classified according to sinus width into narrow, average, and wide, and according to residual bone height into ≤2 and >2 mm.

RESULTS

A total of 146 implants were installed and 103 biopsies were evaluated. New bone formation in sites classified as narrow (69 sites), average (19 sites), and wide (15 sites) was 28.5% ± 9.24, 28.9% ± 8.61, and 30.3% ± 7.80, respectively. The mean posterior maxillary residual bone height was 4.0 ± 2.43 mm, and 26 and 77 sites were classified as ≤2 and >2 mm, respectively. New bone formation was 26.2% ± 9.10 and 29.8% ± 8.67 for residual bone height ≤2 and >2 mm, respectively. The differences were non-significant.

CONCLUSIONS

Within the limitations of the present study, posterior residual bone height and sinus width were not factors with influence on new bone formation in sinuses grafted exclusively with anorganic bovine bone after 8 months of healing.

A 2-year prospective case series on volumetric changes, PROMs, and clinical outcomes following sinus floor elevation using deproteinized bovine bone mineral as filling material

BACKGROUND

A sinus floor augmentation may be indicated when a lack of hard tissue impedes implant placement. Although clinically successful, evidence supporting the long-term three-dimensional stability of the grafted volume is scarce. Second, evidence on the patient's acceptance of this type of treatment is limited.

PURPOSE

First is to evaluate the changes in graft volume after lateral wall sinus lifting based on superimposed cone beam computed tomography (CBCT) images and then to assess patient-reported outcome measures (PROMs) and clinical outcomes.

MATERIALS AND METHODS

Partially edentulous patients in need of a sinus lift and fixed reconstruction on at least two neighboring implants were selected for a prospective case series. Lateral wall sinus augmentation was performed using deproteinized bovine bone mineral (DBBM) as the only filling material. Volumetric changes were quantified on the basis of a preoperative CBCT and three postoperative CBCTs (at 2 weeks, 3 months, and 2 years). PROMs and clinical parameters were registered.

RESULTS

Twenty-two patients (7 males, 15 females; mean age 59 years) participated of which three patients dropped out during the follow up. Graft volumes amounted to 1418.26 mm³ at 2 weeks, 1201.21 mm³ at 3 months, and 1130.13 mm³ at 2 years postoperative pointing to a relative graft volume stability of 79.7%. Swelling was the leading symptom during the first week. A peak in visual analogue scale scores was observed for pain, swelling, and hematoma the day of surgery and 1 day postoperation with a statistically significant decline between days 3 and 7. Hemorrhage and nose bleeding occurred in 18.2% and 27.3% of the subjects, respectively. About 95.5% of the subjects would undergo the treatment again. All implants integrated successfully and demonstrated healthy clinical conditions.

CONCLUSION

Lateral wall sinus augmentation using DBBM as the only filling material is a viable treatment concept given limited graft resorption, good patients' tolerance, and clinical outcomes.

A Sinus Floor Reaugmentation Technique Around an Apically Exposed Implant Into the Maxillary Sinus

Sinus floor augmentation (SFA) is the most predictable treatment option in the atrophic posterior maxilla. However, exposure of the apical implant body into the maxillary sinus cavity is an occasionally observed phenomenon after SFA. Although most penetrating dental implants remain completely asymptomatic, they may induce recurrent rhinosinusitis or implant loss. Removal of the implant should be considered if there is significant implant exposure that results in prolonged treatment and increased costs. This case report demonstrates a recovery approach using sinus floor reaugmentation without implant removal in a patient with an apically exposed implant into the maxillary sinus cavity.

Modified Disk-Up Sinus Reamer for Sinus Floor Elevation and Simultaneous Implant Placement: An Animal Study with Miniature Pigs

Objective: The disk-up sinus reamer (DSR) is a modified instrument used to elevate the maxillary sinus floor. This study aimed to compare the effects of modified DSR sinus floor elevation (DSFE) with osteotome sinus floor elevation (OSFE), both with simultaneous implant placement. Methods: Twelve miniature pigs were treated with DSFE on one side and OSFE on the other. Implants 9 mm in length were placed in six pigs without grafting, while implants 11 mm in length were placed in the other six pigs with grafting. After submerged healing for 3 months, vertical bone gain (VBG), general and histological observation, and bone contact ratio (BCR) were analyzed. Results: The mean maxillary residual bone height (RBH) when implants were placed was 6.45 ± 0.36 mm. In the no-grafting group, DSFE and OSFE had a similar VBG after 3 months. The grafting group with DSFE recorded a significantly higher VBG (VBG0: 7.83 ± 0.44 mm, VBG1: 7.54 ± 0.40 mm) than the graft group with OSFE (VBG0: 5.45 ± 0.56 mm, VBG1: 4.34 ± 2.15 mm) (p < 0.05). One implant became loose and the sinus mucosa of three pigs appeared metallic in color on the control side (OSFE). Conclusions: The effect of OSFE and DSFE is similar when there is no need for grafting. DSFE seems a better alternative method for sinus floor elevation with grafting when more VBG is needed.

The Relationship between Maxillary Sinus Lateral Wall Thickness, Alveolar Bone Loss, and Demographic Variables: A Cross-Sectional Cone-Beam Computerized Tomography Study

OBJECTIVES

Sinus floor elevation and augmentation surgery is widely used as a reliable procedure to increase insufficient bone height in the posterior maxillary area. The purpose of the present clinical study was to determine the associations between periodontal bone loss (PBL), maxillary sinus lateral bone wall thickness, age, and gender using cone-beam computerized tomography (CBCT).

MATERIALS AND METHODS

The current retrospective study consists of 716 maxillary sinus CBCT images of 358 patients. The CBCT scans were assessed to detect the relationship between lateral wall thickness and PBL. ANOVA and Student t test analysis were used to determine the influence of PBL on sinus lateral wall thickness.

RESULTS

Sinus lateral wall thickness was significantly associated with PBL (p < 0.05) at 3, 13, and 15 mm height. There was no significant association between lateral wall thickness and gender (p > 0.05). However, there was a significant association between lateral wall thickness at 3 and 13 mm and age (p < 0.05). There were significant associations between PBL and age (p < 0.001), and PBL and gender (p < 0.05).

CONCLUSIONS

PBL might have an association with maxillary sinus lateral bone wall thickness. Further studies are needed to confirm this possible relationship.

The value of the apparent diffusion coefficient calculated from diffusion-weighted magnetic resonance imaging scans in the differentiation of maxillary sinus inflammatory diseases

OBJECTIVES

This study examined the value of the apparent diffusion coefficient (ADC) calculated by using diffusion-weighted imaging (DWI) in the differentiation of inflammatory lesions of the maxillary sinus.

STUDY DESIGN

Sixty-five maxillary sinus magnetic resonance imaging (MRI) scans with findings suggestive of inflammatory lesions were qualitatively categorized into 4 distinct groups by using T2-weighted images: group 1: presence of mucosal thickening; group 2: presence of sinonasal polyps or mucous retention cysts; group 3: presence of fluid identified by air-fluid levels with a homogeneous signal intensity; and group 4: presence of fluid identified by air-fluid levels with a heterogeneous signal intensity. The ADC of each imaging finding was measured by using a 5-mm area of interest. Statistical differences between the groups were determined by using nonparametric tests with a 5% significance level.

RESULTS

Statistically significant differences were observed between group 1 and the other groups. Mucosal thickening was associated with lower ADC values compared with the other inflammatory lesions.

CONCLUSIONS

The ADC can be useful in differentiating mucosal thickening from other inflammatory alterations in the maxillary sinuses. Mucosal thickening had more restricted water diffusion compared with the other inflammatory lesions.

Potential risk factors for maxillary sinus membrane perforation and treatment outcome analysis

BACKGROUND

Most common complication of sinus floor elevation (SFE) is sinus membrane perforation (SMP).

PURPOSE

To investigate the correlation between SMP and potential risk factors and to evaluate SMP treatment outcomes.

MATERIALS AND METHODS

This study included patients who had undergone a SFE at Division of Oral Surgery and Orthodontics, Medical University of Graz from 2013 to 2017. Analysis of patients' records and CBCT focused on patient-related risk factors (sinus contours, thickness of membrane and lateral sinus wall, interfering septa, crossing vessels, former oroantral communication) and intervention-related risk factors (surgical approach, sides, number of tooth units, and sites). The outcome of SMP treatment was analyzed in the recalls.

RESULTS

In all, 121 patients underwent 137 SFE. There were 19 cases of SMP (13.9%). Two significant factors were identified: maxillary sinus contours (P = .001) and thickness of the sinus membrane (P = .005). The sinus membrane perforation rate was highest in narrow tapered sinus contours and when the sinus membrane was thinner than 1 mm. Among 19 cases with SMP, no complications were seen upon recall.

CONCLUSIONS

Maxillary sinus contours and sinus membrane thickness seem to be relevant factors for SMP. Sinus membrane perforations were successfully treated by coverage with collagen membrane.

Bone Augmentation and Bilateral Sinus Elevation at a Female Patient with Type 2 Diabetes

Introduction. Chronic periodontal diseases and dental caries are the primary reasons for tooth loss in adults, which is further increased in people with diabetes. In most cases of bone loss, the treatment of partial edentulous patients with implant supported restorations impose additional surgical procedures, like sinus lift elevation and bone augmentation, which can complicate the healing process.

Case report. This case report presents a type 2 diabetes female patient with several oral health problems, like periodontal disease, poor decay control, bad oral hygiene, a severe maxillary atrophy and the presence of a large maxillary periapical cyst. After a careful examination, based on clinical and radiographic findings, a comprehensive treatment plan was established. The sequential treatment plan consists in extraction, surgical removal of periapical cyst, bilateral external sinus lift procedures and bone augmentation. The surgical protocol was adapted to the particular health conditions of this type 2 diabetes patient.

Conclusion. Sinus elevation and bone augmentation are predictable procedures often required when restoring the posterior maxilla with dental implants. In case of diabetes patients with bone resorption and defects due to periapical cyst, if the correct protocol is followed, no post-surgical complications and good result in bone augmentation can be attaint.

Clinical evaluation of modified transalveolar sinus floor elevation and osteotome sinus floor elevation in posterior maxillae: study protocol for a randomized controlled trial

BACKGROUND

Implant placement in the posterior maxilla is often complicated by the insufficient bone volume. While transalveolar sinus floor elevation (TSFE) has been proven as a predictable surgical procedure to increase the bone height in the posterior maxilla, questions in regard to the necessity of the bone grafting during the sinus lift and the question of whether TSFE could be performed when the residual bone height is below 5 mm are still debated. Furthermore, high-quality evidence comparing the clinical outcome of transalveolar sinus floor elevation with osteotome and modified sinus floor elevation with crestal non-cutting drills is limited.

METHODS/DESIGN

One hundred twenty adult patients who fit the inclusion criteria are being recruited from the Peking University Hospital of Stomatology First Clinical Division (Beijing, China). All patients are assigned to one of four groups according to a table of random numbers. Participants will receive (1) TSFE using osteotomes with bone grafting, (2) TSFE using osteotomes without bone grafting, (3) modified TSFE with bone grafting, or (4) modified TSFE without bone grafting. In a one-year follow-up period, implant survival rates, complications, implant stability, bone remodeling around the implant, and patient-reported outcome (visual analog scale for intraoperative discomfort and postoperative pain) will be observed and documented. The implant stability will be gauged by the resonance frequency analysis six times (at baseline and weeks 6, 8, 12, 16, and 26), and the bone remodeling will be observed and compared via radiographic examinations.

DISCUSSION

The result of the trial will potentially contribute to better decision making in atrophic posterior maxilla when implant placement is needed. Therefore, if the outcome is deemed favorable, the use of the modified TSFE would achieve an outcome equivalent to that of the traditional TSFE while introducing less trauma and postoperative discomforts. Separately, whether the bone graft procedure is necessary for the TSFE will also be discussed.

TRIAL REGISTRATION

The study has been registered in ClinicalTrials.gov under the identifier number NCT03445039 . Registered on 26 February 2018.

Retrospective Analysis of Sinus Membrane Thickening: Profile, Causal Factors, and Its Influence on Complications

PURPOSE

To retrospectively determine the profile of the sinus membrane (SM), potential factors affecting SM thickening (SMT), and the correlation between SMT and sinus augmentation (SA) complications.

MATERIALS AND METHODS

In the patients who received lateral SA, SMT was classified in sagittal sections of cone-beam computed tomography according to its thickness and morphology. The correlation between SMT and the following factors was analyzed: age, sex, endodontic and periodontic statuses of neighboring teeth, and shape of the sinus inferior border. The association between SMT and SA complications was investigated.

RESULTS

SMT of ≤2 mm was prevalent (60%). Irregular SM was mostly observed for SMT of >2 mm. There was no statistically significant association between SMT and the included factors. SMT did not significantly correlate with either perforation or postoperative complications. There was a statistically significant increase in implant failure when SMT was >2 mm, but it was hard to determine that the failure was solely affected by SMT.

CONCLUSION

SMT was not influenced by the factors included in this study, and it might not be a risk factor for SA and implant failure.

Micro-CT evaluation of the cortical bone micro-architecture in the anterior and posterior maxilla and the maxillary sinus floor

OBJECTIVES

To perform a within-subject comparison of the cortical bone micro-architecture of the maxillary sinus floor (MSF) to that of the buccal aspect of the anterior and posterior maxilla.

METHODS

Micro-CT scans of the buccal aspect of the anterior and posterior maxilla and of the MSF in 14 human anatomical specimens were recorded. Within-subject comparisons were performed for cortical thickness (Ct.Th) and porosity (Ct.Po), average pore volume (AvgPo.V), and pore density (Po.Dn).

RESULTS

The MSF presented the lowest and the anterior maxilla the highest Ct.Th, while Ct.Po was significantly higher at the MSF compared to the posterior maxilla (p = 0.021). No relevant differences were recorded for AvgPo.V and Po.Dn among regions (p > 0.067). Further, an increased Ct.Th at the MSF was significantly associated with a lower Po.Dn, while a higher Ct.Th and an increased AvgPo.V in the anterior maxilla were associated with a higher Ct.Th and an increased AvgPo.V, respectively, in the posterior maxilla and MSF. Finally, within each region, the AvgPo.V was associated positively with Ct.Po and negatively with Po.Dn.

CONCLUSIONS

The cortical bone of the MSF is slightly less thick and slightly more porous compared to the cortical bone at the buccal aspect of the anterior and posterior maxilla.

CLINICAL RELEVANCE

During lateral and vertical bone augmentation procedures, the cortical recipient bone is perforated several times to open the bone marrow compartment to facilitate provision of osteoinductive cells and molecules in the augmented space. Whether it is meaningful to approach the MSF in a similar way during MSF augmentation procedures or whether the slightly more porous structure of the MSF observed herein reduces the cortical barrier function already sufficiently has to be assessed in future clinical trials.

Maxillary Sinus Floor Augmentation to Enable One-Stage Implant Placement by Using Bovine Bone Substitute and Platelet-Rich Fibrin

Nowadays it is possible to perform an optimal implant placement and to achieve a good long-term prognosis for an implant-borne prosthesis in the grafted posterior maxilla. This study evaluates the efficiency of one-stage piezosurgery by using as graft material a combination of particulate bovine bone substitutes with platelet-rich fibrin to achieve sinus lift. We included in this study 14 cases of one-stage sinus lift surgeries during which we placed 30 standard implants. The mean vertical bone height gain was 10.12 mm six months after surgery, and the mean postoperative follow-up time was 43.79 months. There were no major complications during or after surgery, and all implants are in use. Therefore, it can be concluded that one-stage sinus piezosurgery using particulate bovine bone substitutes and platelet-rich fibrin can be applied as a predictable and effective technique in the treatment of the posterior edentulous maxilla ensuring 4-5 mm vertical bone height.

Histologic and Histomorphometric Analysis of Bone Regeneration with Bovine Grafting Material after 24 Months of Healing. A Case Report

Anorganic bovine bone mineral matrix (ABBMM) has been reported to have osteoconductive properties and no inflammatory or adverse responses when used as grafting material in sinus augmentation procedures. However, controversy remains in regard to degradation rate of ABBMM. The aim of this study was to histologically and histomorphometrically evaluate the degradation of ABBMM in human bone samples obtained in one patient 24 months after sinus augmentation. Materials and Methods: The histologic and histomorphometric analysis was performed by means of light microscopy in three specimens harvested from the same patient, Results: After 24 months the tissue pattern appeared to be composed of residual particles, some in close contact with the newly formed bone, others separated by translucent areas and osteoid tissues. Newly-formed bone presented different levels of maturation and numerous osteocytes, with greater numbers in bone closer to the grafted particles (27.3% vs. 11.2%, p < 0.05). The histomorphometric analysis showed mean values of 40.84% newly-formed bone, 33.58% residual graft material, 23.84% marrow spaces, and 1.69% osteoid tissue, Conclusions: Even though ABBMM underwent considerable resorption, a great amount of residual grafting material was still present after two years of healing following sinus augmentation. This study confirms that the bovine grafts can be classified as long-term degradation materials.

Devitalization of adjacent teeth following maxillary sinus floor augmentation: A retrospective radiographic study

BACKGROUND

Elevation of the schneiderian membrane, during maxillary sinus floor augmentation (MSFA) may theoretically result in devitalization of adjacent teeth, which are in a close spatial relationship to the sinus floor.

PURPOSE

To assess retrospectively the probability of devitalization of teeth adjacent to the osteotomy site after MSFA in a relatively large number of patients.

MATERIALS AND METHODS

All MSFA procedures, performed at a university oral surgery clinic within a time period of 10 years, were assessed on the following eligibility criteria: (1) presence of vital teeth (ie, not root canal treated and no periapical radiolucency on a panoramic radiograph taken just after MSFA), (2) presence of a 3 to 12 months postoperative radiograph of the teeth adjacent to the osteotomy site displaying the root apices, and (3) complete medical records up to at least 12 months postoperatively. The radiographs of the different time points were compared and any changes in the radiographic status of the adjacent teeth (eg, development of a periapical lesion, root canal treatment, etc.) were recorded and the spatial relationship of the adjacent teeth to the maxillary sinus classified.

RESULTS

Out of 684 MSFAs, 257 fulfilled the inclusion criteria and involved 357 adjacent teeth, of which 221 presented close to and/or intimate relationship to the sinus. In only a single case, tooth vitality might have been lost due to the procedure. Thus, the probability for tooth devitalization for teeth with close to and/or intimate spatial relationship to the sinus floor ranged from 0.45% to 0.7%.

CONCLUSIONS

Even for teeth with apices very close to and/or intimately related to the sinus tooth devitalization after MSFA is an extremely rare complication; that is, the probability of tooth devitalization after MSFA is ≤0.7%.