Transcrestal Sinus Floor Elevation With a Minimally Invasive Technique

A transcrestal sinus floor elevation strategy based on a haptic robot system: An in vitro study

OBJECTIVES

To reveal the force profiles recorded by haptic autonomous robotic force feedback during the transcrestal sinus floor elevation (TSFE) process, providing a reference for the surgery strategy during TSFE.

MATERIALS AND METHODS

A total of 42 maxillary sinus models with different angles of the sinus floor (30°, 40°, 50°, 60°, 70°, 80°, and 90°, compared to vertical plane) were 3D printed. Implant site preparation was performed using a robotic system, and the total force (Ft) and axial force along the drill (Fz) during the surgery were recorded by the haptic robotic arm. The actual initial breakthrough point (drill contacting sinus floor) and complete breakthrough point (drill penetrating the sinus floor) were defined visually (the actual IBP and the actual CBP). The theoretical initial breakthrough point (the theoretical IBP) and the theoretical complete breakthrough point (the theoretical CBP) defined by the robot-guided system and the CBCT were determined by real-time force feedback and imaging distance measurement, respectively. The distance from the bottom of the resin model to the actual IBP and the actual CBP was defined as Di and Dt, respectively.

RESULTS

The difference in Fz began to increase significantly at 70°, while the difference in Ft became significant at 60°. When the angle was greater than 70°, there was no significant difference in the discrepancy between the actual and theoretical perforation points. Compared to judging the breakthrough point by CBCT, real-time force feedback TSFE under robotic surgery achieved more accurate initial breakthrough point detection.

CONCLUSIONS

The smaller the angle, the larger the breakthrough force for the drill. The real-time force feedback of haptic robotic system during TSFE could provide reliable reference for dentists. More clinical studies are needed to further validate the application of robotic surgery assisted TSFE.

APCs in sinus floor augmentation

After tooth loss in the posterior area of the maxilla, sinus floor elevation is often required to compensate the vertical bone loss due to sinus pneumatization. This narrative review reports on the potential benefits of autologous platelet concentrates (APCs) during this procedure. As for transcrestal approach, APCs have been used as "sole" substitute/graft. However, because of the low number of clinical trials available with PRGF, and even none for PRP, no definitive conclusions can be made regarding their efficacy. The number of studies on the use of L-PRF were outnumbered indicating good feasibility for vertical bone gain, with a high implant survival rate and a low degree of complications. PRP and PRGF have not been studied as a "single/sole" substitute for a one-stage lateral window approach, probably because of the weak physical characteristics of the membranes. L-PRF alone appears to be a predictable grafting material for lateral maxillary sinus grafting and a reduced RBH should not be considered as a risk factor. Compared to a "standard" bone substitute L-PRF shows slightly less vertical bone gain (consider enough membrane application and use of bony window as new sinus floor roof over the implant apices), enhanced early resorption (first 6 months after application), but a similar stable bone gain afterward. For a two-stage lateral window approach, APCs "alone" cannot be recommended, due to their weak withstand to the sinus pneumatization forces. APCs combined with bone substitutes seem to accelerate bone formation, without any additional benefits on the long-term new bone gain. The use of L-PRF membranes for the treatment of perforations appears to be an effective treatment option, but further clinical studies are needed to confirm this. Even though the abovementioned statements are based on large numbers of studies, additional RCTs comparing APCs with different types of grafting procedures for sinus elevation are needed.

Mini Crestal Sinus Lift With Bone Grafting and Simultaneous Insertion of Implants in Severe Maxillary Conditions as an Alternative to Lateral Sinus Lift: Multicase Study Report of Different Techniques

The present study evaluates the efficacy and clinical outcomes of crestal sinus lift techniques used to elevate the sinus floor simultaneously with bone grafting and implant placement as a possible and reproducible alternative to lateral sinus lift. Patients underwent different crestal sinus elevation techniques. The heterologous biomaterial was used as graft material, and multiple implants were placed simultaneously after sinus augmentation. Radiographic and clinical examinations were performed during follow-up. All procedures were successfully performed without any apparent perforation of the Schneider membrane. The sinus floor was augmented with an average height of 5 mm (range: 2.8-7.4 mm). The implants healed smoothly with healing screws. Peri-implant marginal bone was stable with a mean follow-up of 50 months (range: 33-71 mo). No complications were observed during the follow-up. Based on the limited data collected in this study, the new crestal sinus elevation approach can effectively raise the sinus floor and reduce the incidence of postoperative complications. Other cases with long-term follow-up are needed to confirm and improve this crestal sinus lift technique.

Six-year extension results of a randomized trial comparing transcrestal and lateral sinus floor elevation at sites with 3-6 mm of residual bone

OBJECTIVES

To comparatively evaluate the 6-year outcomes of transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively).

METHODS

The 54 patients representing the per-protocol population of a randomized trial comparing implant placement with simultaneous tSFE versus lSFE at sites with a residual bone height of 3-6 mm were invited to participate in the 6-year follow-up visit. Study assessments included: peri-implant marginal bone level at the mesial (mMBL) and distal (dMBL) aspects of the implant, proportion of the entire implant surface in direct contact with the radiopaque area (totCON%), probing depth, bleeding on probing, suppuration on probing, and modified plaque index. Also, the conditions of the peri-implant tissues at 6-year visit were diagnosed according to the case definitions of peri-implant health, mucositis, and peri-implantitis from the 2017 World Workshop.

RESULTS

Forty-three patients (21 treated with tSFE and 22 treated with lSFE) participated in the 6-year visit. Implant survival was 100%. At 6 years, totCON% was 96% (IR: 88%-100%) in tSFE group and 100% (IR: 98%-100%) in lSFE group (p = .036). No significant intergroup difference in patient distribution according to the diagnosis of peri-implant health/disease was observed. Median dMBL was 0.3 mm in tSFE group and 0 mm in lSFE group (p = .024).

CONCLUSIONS

At 6 years following placement concomitantly with tSFE and lSFE, implants showed similar conditions of peri-implant health. Peri-implant bone support was high in both groups and was slightly but significantly lower in tSFE group.

Complications of sinus floor elevation procedure and management strategies: A systematic review

AIM

This systematic review aimed to investigates the types and incidences of complications following sinus floor elevations (SFE) along with their prevention and management strategies.

MATERIALS AND METHODS

Electronic database and hand search were conducted to screen the literature published from January 1960 to June 2021. The selected studies had to report well-described SFE techniques, complications during, and post-SFE. Data extraction included types of SFE techniques, complications, and their treatment strategies.

RESULTS

A total of 74 studies with 4411 SFE procedures met the inclusion criteria. Different SFE techniques demonstrated varying patterns for both complications and complication rates. Postoperative pain, swelling, and edema were widely reported. The most common complications that required intervention following Lateral SFE (LSFE) were sinus membrane perforation (SMP), wound dehiscence, graft exposure and failure, and sinusitis. LSFE had more SMPs and sinusitis cases compared with a transcrestal SFE (TSFE). The presence of benign paroxysmal positional vertigo following TSFE was significant in certain selected studies.

CONCLUSION

Given the inherent limitations, this systematic review showed distinct features of complications in SFE using varying techniques. Treatment planning for these procedures should incorporate strategies to avoid complication occurrence.

Sinus augmentation procedure via the lateral window technique-Reducing invasiveness and preventing complications: A narrative review

Sinus augmentation has become an integrated surgical phase in posterior maxillary implant prosthesis reconstruction. Since the residual alveolar bony height usually requires additional volume particularly at this anatomical region, sinus floor augmentation is advocated routinely. Over the years, Implant success rate is proved to be comparable to the one in the pristine bone, which is well documented in the literature. Anatomical aspects as well as surgeon skills are at most importance to achieve predictable outcome. In this narrative review, the different osteotomy techniques, the indications toward 1 or 2-stage approaches, the control of the Schneiderian membrane integrity as well as the management of intra- and post-operative complications are thoroughly discussed according the current data. In light of the excellent long-term implant success rate concurrent with the application of contemporary advanced techniques of the sinus augmentation via the lateral wall osteotomy approach, reduce invasiveness and less complication occurrences are well documented. A well-codified patient selection involving the rhinologist as an integral medical team would be significantly beneficial toward early diagnosis. In-depth knowledge of the anatomy, execution of a well standardized surgical technique, and understanding the complication etiology and their management are prerequisites for reducing patient morbidity to minimal discomfort and predictable successful outcome.

Minimal invasiveness in the transcrestal elevation of the maxillary sinus floor: A systematic review

In the attempt to reduce the invasiveness of a transcrestal sinus floor elevation procedure, different aspects must be considered; that is, the minimization of intra- and postsurgery morbidity, the reduction of treatment time, and the simplification/elimination of the reconstructive technology. Within this context, a systematic literature search was performed for controlled clinical trials evaluating the impact of one or more of these aspects on transcrestal sinus floor elevation invasiveness. Nineteen articles (15 studies) were included. Overall, the results confirmed that transcrestal sinus floor elevation is a minimally invasive and effective option for bone augmentation in the edentulous, atrophic posterior maxilla. By using powered instruments rather than manual osteotomes and hand mallet, the invasiveness of transcrestal sinus floor elevation can be further reduced without affecting its clinical effectiveness. To impact effectively on morbidity, the key elements to consider when selecting instruments for transcrestal sinus floor elevation are (a) their availability as a standardized sequence, to be adapted on predetermined residual bone height, and (b) the possibility to control pressure (eg, with screwable osteotomes) and/or instrument excursion (eg, with stop devices) to fracture the maxillary sinus floor. Among powered instruments, a standardized sequence of drills incorporating a trephine drill seem to be particularly indicated, due to reduced chair time, high tolerability for the patient, and the possibility to isolate a bone core to implement histomorphometric outcomes. At molar extraction sites with an interradicular septum characterized by a height of at least 4 mm, immediate transcrestal sinus floor elevation and implant placement can be considered a valid option to shorten treatment time.

Peri-implant tissue conditions following transcrestal and lateral sinus floor elevation: 3-year results of a bi-center, randomized trial

Objectives

The present study was performed to comparatively evaluate the peri-implant bone stability and conditions of marginal tissues at 3 years following transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively).

Materials and methods

Patients included in a parallel-arm randomized trial comparatively evaluating tSFE and lSFE were recalled at 3 years post-surgery. Twenty-one and 24 patients in tSFE and lSFE groups, respectively, participated in the follow-up visit. Peri-implant bone support was evaluated as the proportion of the entire implant surface in direct contact with the radiopaque area (totCON%) on 3-year periapical radiographs. The conditions of the marginal peri-implant tissues at 3-year visit were classified as peri-implant health, peri-implant mucositis, or peri-implantitis.

Results

At 3 years, both groups showed an implant survival rate of 100%. Median totCON% was stable at 3 years, being 100% in both groups (p = 0.124). Peri-implant health and mucositis were diagnosed in 10 (47.6%) and 11 (52.4%) patients, respectively, in the tSFE group, and in 8 (33.3%) and 16 (66.7%) subjects, respectively, in the lSFE group (p = 0.502).

Conclusions

At 3 years following surgery, implants placed concomitantly with tSFE and lSFE fully maintain peri-implant bone support. Peri-implant mucositis was the most prevalent condition, with a similar prevalence between groups.

Clinical relevance.

Based on 3-year data on peri-implant bone support and prevalence of peri-implant diseases, the study suggests that tSFE and lSFE represent two equally valid options for the rehabilitation of the posterior maxilla. ClinicalTrials.gov ID: NCT02415946.

Implant-supported rehabilitation following transcrestal and lateral sinus floor elevation: analysis of costs and quality of life from a bi-center, parallel-arm randomized trial

AIM

to comparatively evaluate costs and specific aspects of oral-health related quality of life (OhRQoL) related to the period between the surgery phase of transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively) and 6 months after delivery of implant-supported prosthesis.

METHODS

A bi-center, parallel-arm, randomized trial comparatively evaluating tSFE and lSFE when applied concomitantly with implant placement was conducted. At 6 months after prosthesis delivery, data on cost-associated items related to the post-surgery period and selected aspects of OhRQoL were collected.

RESULTS

Analyses of costs and quality of life was conducted on 56 patients (tSFE: 28; lSFE: 28) and 54 patients (tSFE: 26; lSFE: 28), respectively. Significantly lower dose of anesthetic (2 vs 3 vials), amount of xenograft (420 mg vs 1975 mg), and duration of surgery (54' vs 86') were observed for tSFE compared to lSFE. No significant differences in the number of additional surgical sessions, postoperative exams, specialist consultations and drug consumption were found between groups. In a limited fraction of patients in both groups, improvements were observed for pain (tSFE: 3.8%; lSFE: 7.4%), comfort in eating any food (tSFE: 11.5%; lSFE: 3.6%), self-consciousness (tSFE: 19.2%; lSFE: 14.3%), and satisfaction about life (tSFE: 19.2%; lSFE: 10.7%).

CONCLUSIONS

The surgery phase of maxillary sinus floor elevation is characterized by more favorable cost-associated items for tSFE compared to lSFE. Differently, tSFE and lSFE do not differ for either costs related to the post-surgery phases or impact of the implant-supported rehabilitation on specific aspects of OhRQoL.

Long-term outcomes of osteotome sinus floor elevation with or without bone grafting: The 10-year results of a randomized controlled trial

AIMS

To assess the long-term clinical and radiographic results of implants placed using osteotome sinus floor elevation (OSFE) with or without bone grafting.

MATERIALS AND METHODS

Forty-five patients were randomly assigned into two groups: Group 1 (OSFE with deproteinized bovine bone mineral) and Group 2 (OSFE without grafting). The patients were recalled at 1, 3, 5 and 10 years after surgery. The implant survival, endo-sinus bone gain (ESBG), marginal bone loss (MBL), peri-implant bone height (PBH, distance from the most coronal level to the most apical level of bone-to-implant contact), prosthesis survival and hardware complications, and peri-implant soft tissue conditions were assessed.

RESULTS

Forty patients attended the 10-year examination. Mean residual bone height was 4.58 ± 1.28 mm. The 10-year cumulative survival rate was 90.7% for Group 1 and 95.0% for Group 2. The PBH was 5.89 ± 1.24 mm for Group 1 and 5.74 ± 1.43 mm for Group 2 at 10 years. The ESBG of both groups remained stable after 3 years. Two-thirds of the implants were free of hardware complications. No significant differences in MBL and peri-implant tissue parameters were found.

CONCLUSION

OSFE with or without grafting both yielded predictable clinical outcomes with similar PBH (ClinicalTrials.gov. NCT01619956).

The impact of graft remodeling on peri-implant bone support at implants placed concomitantly with transcrestal sinus floor elevation: A multicenter, retrospective case series

OBJECTIVES

To evaluate the impact on peri-implant bone support (as assessed on periapical radiographs) of the remodeling dynamics of varying graft biomaterials used for transcrestal sinus floor elevation (tSFE).

METHODS

The study is a multicenter, retrospective series of cases undergone tSFE (performed according to the Smart Lift technique) and concomitant implant placement. At operator's discretion, tSFE was performed with bone core (BC) alone or supplemented by deproteinized bovine or porcine bone mineral (DBBM and DPBM, respectively), synthetic hydroxyapatite in a collagen matrix (S-HA), or ß-tricalcium phosphate (ß-TCP). Immediately after surgery, at 6-12 months post-surgery, and at later (≥24 months) follow-up intervals, the percentage proportion of the implant surface in direct contact with the radiopaque area was calculated for the entire implant surface (totCON%). Also, the height of the graft apical to the implant apex (aGH) was assessed.

RESULTS

At 6-12 months following tSFE, median totCON% was 100%, with a median aGH of 1.4 mm. A tendency of aGH to decrease in height was observed at later follow-up intervals for sites treated with all grafting procedures. In all treatment groups, the majority of the implant surface was still surrounded by the radiopaque area at the longest follow-up visits.

CONCLUSIONS

Although the height of the peri-implant radiopaque area apical to the implant apex tends to reduce overtime at sites which have received tSFE, the peri-implant bone support seems to be maintained long term irrespective of the graft material used.

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.

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).

Morbidity following transcrestal and lateral sinus floor elevation: A randomized trial

Aim

To comparatively evaluate the morbidity following maxillary sinus floor elevation according to either transcrestal (tSFE) or lateral (lSFE) approach with concomitant implant placement.

Materials & Methods

Patients with ≥1 edentulous maxillary posterior site with residual bone height (RBH) of 3–6 mm were enrolled. tSFE was performed in association with a xenograft and a collagen matrix. For lSFE, the sinus was grafted with the xenograft, and the antrostomy was covered with a membrane. Implants were inserted concomitantly. The postoperative course was assessed through questionnaires. Pain level (VAS_pain) was recorded using a 100‐mm visual analogue scale.

Results

Twenty‐nine and 28 patients were included in tSFE and lSFE group, respectively. On the day of surgery, VAS_pain was significantly higher for tSFE compared to lSFE, and similar from day 1 to 14. tSFE was characterized by significantly lower incidence of swelling, bruising and nasal discharge/bleeding. Significantly less severe limitation in swallowing, continuing daily activities, eating, speaking, opening the mouth and going to school/work was found for tSFE only at specific postsurgery intervals.

Conclusions

lSFE was associated with lower pain on the day of surgery, and tSFE revealed lower postoperative morbidity as well as more tolerable postoperative course.

Influence of Maxillary Sinus Width on New Bone Formation After Transcrestal Sinus Floor Elevation: A Proof-of-Concept Prospective Cohort Study

PURPOSE

Graft maturation in the maxillary sinus requires adequate angiogenesis and osteoprogenitor cells migration from the surrounding bony walls: the aim of this study was to analyze the correlation between sinus cavity dimensions and new bone formation after transcrestal sinus floor elevation (tSFE).

METHODS

Patients needing maxillary sinus augmentation (residual crest height ≤ 4 mm) were treated with tSFE using xenogeneic granules. Six months later, bone-core biopsies were retrieved for histological analysis in the implant insertion sites. Buccopalatal sinus width (SW) was evaluated on cone beam computed tomography, and correlations between histomorphometric and anatomical parameters were quantified by means of linear regression analysis.

RESULTS

Eight consecutive patients underwent tSFE procedures: at 6 months, average percentage of newly formed bone resulted 24.2% ± 7.9%. Statistical analysis showed a strong inverse correlation between SW and new bone formation (R = 0.88), and a strong direct correlation between the number of exposed bone walls and new bone formation (R = 0.82).

CONCLUSION

Within the limitations of this proof-of-concept study, in which a restricted number of patients were analyzed, tSFE showed more predictable results in narrow than in large sinuses, in terms of new bone formation.

CBCT imaging of the alveolar bone structure in maxilla of elderly donor cadavers and PCA analysis

There is an important bone matrix with remodelling between dentate and edentulous samples of the human maxilla for bone metabolism. Cone beam computed tomography (CBCT) is useful for structural analysis of bone. The objective of this study was to investigate morphological data of donor cadavers in detail using CBCT imaging and principal component analysis (PCA). We analysed 38 donor cadavers using a CBCT apparatus. The analytical results defined differences in skull measurement parameters and dentate and edentulous levels using PCA. We observed cortical bone, trabecular bone, and the distance from the bottom of the maxillary sinus to the oral mucosa at a right angle to the palatal plane of the first molar region between dentate and edentulous samples of the human maxilla using CBCT imaging. In the dentate sample of the maxilla, component 1 was defined by negative contributions from gender (-0.84) and age (-0.54) to positive contributions such as cortical bone structure (CBS, 0.68) and trabecular bone structure (TBS, 0.50). There was a difference in CBS between dentate and edentulous human maxilla samples. This study of CBCT data provides useful basal information for planning dental implant surgery using PCA.

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.

Learning Curve of a Minimally Invasive Technique for Transcrestal Sinus Floor Elevation: A Split-Group Analysis in a Prospective Case Series With Multiple Clinicians

AIMS

To assess the learning curve of a minimally invasive procedure for maxillary sinus floor elevation with a transcrestal approach (tSFE) and evaluate the influence of clinician's experience in implant surgery on its outcomes.

MATERIALS AND METHODS

Patients were treated by clinicians with different levels of experience in implant surgery and inexperienced with respect to the investigated tSFE technique. The initial (n = 13) and final (n = 13) groups treated by the expert clinician were compared for tSFE outcomes. Additionally, the high, moderate, and low groups (n = 20 each) treated by the expert, moderately experienced, and low experienced clinician, respectively, were compared.

RESULTS

(1) No significant differences in clinical and radiographic outcomes were observed between initial and final groups; (2) high, moderate, and low groups showed substantial vertical augmentation in limited operation time with treatment outcomes being influenced by the level of experience in implant surgery.

CONCLUSIONS

The investigated technique allows for a substantial vertical augmentation at limited operation times when used by different clinicians. The extent of sinus lift (as radiographically assessed) seems to be influenced by the clinician's level of experience in implant dentistry.

Osteoconductivity of Complex Biomaterials Assayed by Fluorescent-Engineered Osteoblast-like Cells

Biomaterials employed for the bone regeneration can be assayed for specific features such as osteoconductivity and gene expression. In this study, the composite HA/collagen/chondroitin-sulfate biomaterial was investigated using an engineered human cell line, named Saos-eGFP. This cell line, a green fluorescent engineered human osteoblast-like cell, was employed as a cellular model for the in vitro study of biomaterial characteristics. The cytotoxicity was indirectly evaluated by fluorescence detection, osteoconductivity was assayed both by fluorescence and electron microscope analysis as well as cell morphology, whereas the RT-PCR technique was employed to assay gene expression. Saos-eGFP cells viability detection after 24 and 96 h of incubation showed that biomaterial enables the adhesion and proliferation of seeded cells as well as that of the plastic surface, the control. Fluorescence and scanning electron microscopy (SEM) analyses indicated that Saos-eGFP cells were homogeneously distributed on the HA granule surfaces, exhibiting cytoplasmic bridges, and were localized on the collagen-chondroitin sulfate extra-cellular matrix. An expression analysis of specific genes encoding for differentiation markers, showed that biomaterial assayed did not alter the osteogenic pathway of the Saos-eGFP cell line. Our assays confirm the cytocompatibility of this biomaterial, suggesting an osteoconductive capacity mediated by its chemical contents. We showed that the Saos-eGFP cellular model is suitable for in vitro biomaterial assays, and more specifically for assessing osteoconductivity. This result suggests that the cytocompatibility and osteoconductive features of the biomaterial assayed as bone substitute, could have a positive downstream effect on implant osteo-integration.

Ex vivo comparative study on three sinus lift tools for transcrestal detaching maxillary sinus mucosa

The objective of this study was to comparatively evaluate 3 different sinus lift tools, namely umbrella-shaped sinus lift curette YSL-04, our recently designed probe-improved sinus lift curettes, and our newly invented elevator 014, using our previous developed goat ex vivo models for direct visualizing the effectiveness of detaching sinus mucosa in real time. Goat ex vivo models for direct visualizing the effectiveness of detaching sinus mucosa in real time were generated according to our previously developed protocol. The effectiveness for each tool was evaluated through the length of sinus mucosa detached in mesial and distal directions or buccal and palatal directions, and the space volume created by detaching maxillary sinus mucosa in mesial, distal, buccal and palatal directions. The results showed that all 3 sinus lift tools could transcrestally detach the maxillary sinus mucosa and create extra space under the elevated sinus floor on the goat ex vivo sinus models. Moreover, our newly invented elevator 014 had advantages over the other 2 in term of the capability to detach the sinus mucosa. Our newly invented elevator 014 might be a promising tool for detaching maxillary sinus mucosa in transcrestal maxillary sinus floor elevation.

Patient-reported outcomes of implant placement performed concomitantly with transcrestal sinus floor elevation or entirely in native bone

AIM

Based on the hypothesis that maxillary sinus floor elevation with a transcrestal approach (tSFE) does not increase the morbidity of implant surgery, the study evaluated the patient-reported outcomes as well as the type and incidence of complications when implants are placed either concomitantly with tSFE (performed according to Trombelli et al. 2008, 2010a,b) or entirely in native bone.

METHODS

Data from the record charts of patients undergone implant placement for single-tooth rehabilitation in the posterior maxilla were retrospectively obtained from four clinical centers. Cases for tSFE group were included if they showed an extent of sinus lift ≥4 mm concomitantly to implant placement. Cases for N group were included when implant placement was performed entirely in native bone. Patient-reported outcomes had been assessed using 100-mm visual analog scales (postoperative pain, VAS_pain ) and visual rating scales (level of discomfort, VRS_discomfort ; willingness to undergo the same surgery, VRS_willingness ). The dose of analgesics had been self-recorded.

RESULTS

A convenience sample of 14 patients and 17 patients (contributing with one implant site each) treated with tSFE and N, respectively, was obtained for this study. Membrane perforation occurred in 1 tSFE case, without compromising the completion of the procedure. VAS_pain remained low (<12) in both groups. A tendency of VAS_pain to decrease with time was observed in both groups. The area under the curve for VAS_pain (AUC_pain ), indicating the level of pain experience through the first week following surgery, was 18.0 (IR: 8.5-85.0) and 11.5 (IR: 4.5-18.5) in tSFE and N groups, respectively, with no significant inter-group differences (P = 0.084). The dose of analgesics was similarly low between groups. No significant inter-group difference in VRS_discomfort and VRS_willingness was observed.

CONCLUSIONS

Implant placement performed either concomitantly with tSFE (according to Trombelli et al. 2008, 2010a,b) or entirely in native bone is associated with limited incidence of complications, low postoperative pain and medication and are both well tolerated.

Incremental, transcrestal sinus floor elevation with a minimally invasive technique in the rehabilitation of severe maxillary atrophy. Clinical and histological findings from a proof-of-concept case series

In the posterior maxillary sextants, the residual dimensions of the edentulous ridge can considerably limit the insertion of implants with the desired length and diameter. A minimally invasive procedure for transcrestal sinus floor elevation (tSFE), namely the Smart Lift technique, which is based on a standardized sequence of specifically designed drills and osteotomes, was introduced in 2008 and subsequently validated in a series of recent studies. The present technical note describes the use of the technique by a staged approach, called incremental tSFE (i-tSFE), in the augmentation of severely resorbed edentulous ridges. The i-tSFE consists of 2 staged tSFE procedures performed with a transcrestal access, the second of which is performed concomitantly with implant placement. In the present case series, 3 patients with severe bone atrophy (residual bone height, 2 to 3 mm) in the edentulous posterior maxilla were treated with i-tSFE. At the second surgical stage of i-tSFE, implants at least 8 mm long were placed at all sites, and the success of the implant-supported restoration was monitored to 6 months (1 patient) or 3 years (2 patients). Histologic findings from an augmented site showed the presence of newly formed bone, bone marrow spaces with numerous vascular canals, and residual graft particles occupying approximately 50%, 15%, and 35% of the total area, respectively. The results of the study showed that i-tSFE can be performed successfully with the Smart Lift technique to rehabilitate atrophic maxillary posterior sextants.

Comparison of Conventional Transcrestal Sinus Lift and Ultrasound-Enhanced Transcrestal Hydrodynamic Cavitational Sinus Lift for the Filling of Subantral Space: A Human Cadaver Study

The implant-supported prosthetic rehabilitation of the posterior maxilla may require sinus-grafting procedures due to poor quality and low volume of bone. This can be accomplished using a "lateral window" sinus augmentation or with an osteotome sinus floor elevation (OSFE). The hydrodynamic ultrasonic cavitational sinus lift (HUCSL) (Intralift) is derived from the osteotome technique and allows the reduction of some of the traumatic effects of the osteotome technique. The aim of this study was to compare OSFE and the HUCSL procedures on fresh human cadaver heads. Primary outcomes were the height and width of the grafting area in the sinus floor area. Eighty-four maxillary sinuses were selected. On each fresh cadaver head, 2 sinus lifts were done using OSFE and HUCSL in the maxillary sinuses. Computerized tomography scans were performed on each head before and after the surgeries. Measurements were done on radiologic pictures using dedicated software, and the integrity of the sinus membrane was observed after dissecting the maxillae. The use of HUCSL resulted in a significantly higher sinus floor augmentation in the mesio-distal and bucco-palatal direction compared with the osteotome technique (P < .001). There was no correlation between mesio-distal and bucco-palatal diameters of sinus floor augmentation when only the osteotome protocol was considered (r = 0.27 and P = .08). In contrast, the mesio-distal and bucco-palatal diameters of floor augmentation were correlated when the HUCSL protocol was considered (r = 0.79, P < .001). HUCSL represents a good alternative method for sinus floor elevation.

Radiographic outcomes of transcrestal sinus floor elevation performed with a minimally invasive technique in smoker and non-smoker patients

OBJECTIVES

To evaluate the association between smoking status and the outcomes of transcrestal sinus floor elevation (tSFE) performed with a minimally invasive technique (Smart Lift).

METHODS

Forty-five implants were placed in 25 non-smoker (NS) and 20 smoker (S) patients in conjunction with the tSFE procedure. In all cases, an additional graft, chosen among different hydroxyapatite-based or ß-tricalcium phosphate-based biomaterials, was pushed into the sinus by gradual increments. Immediately after surgery, residual bone height, implant penetration into the sinus, extent of sinus lift (SL) and the height of the graft apical to the implant apex (aGH) were assessed on periapical radiographs. At 6 months after surgery, SL and aGH were reassessed.

RESULTS

(i) The Smart Lift procedure resulted in substantial 6-month SL and aGH in both treatment groups; (ii) smoking status did not significantly affect the 6-month radiographic outcomes; (iii) a similarly low incidence of intra- and postoperative complications was observed in NS and S patients.

CONCLUSIONS

Smoking has a limited impact on the outcomes of tSFE performed with the Smart Lift technique.

Distributions of calcitonin gene-related peptide and substance P in the human maxillary sinus of Japanese cadavers

BACKGROUND

Substance P (SP) and calcitonin gene-related peptide (CGRP) are released by the nociceptive sensory nerve and are involved in blood flow, pain and inflammation in the nasal mucosa. The purpose of this study was to assess the distribution of the SP and CGRP nerve fibres related to blood supply within human Schneiderian membrane of the maxillary sinus (MS).

MATERIAL AND METHODS

In this study, the MS from Japanese cadavers was examined by whole-mount immunohistochemistry. Human male cadavers (ranging in age from 80 to 90 years) were used in this study.

RESULTS

SP- and CGRP-positive fibres were found around large vessels of the medialis superior alveolar branches and also within the floor region of the MS. The floor region of the MS was composed of complex branches of these fibres.

CONCLUSION

Our results give useful information for surgical sinus floor elevation in this region of the MS. These anatomical features may assist in the execution of a successful surgical procedure.

Observing the bony canal structure of the human maxillary sinus in Japanese cadavers using cone beam CT

We observed the location of the posterior superior alveolar artery (PSAA) and nerve at the macroscopic level between the maxillary sinus (MS) and surrounding bone of the anterior region of the maxilla. This study was completed using cone beam computed tomography (CBCT) imaging of 19 human cadavers with 38 sides of Japanese origin (ranging in age from 59-94 years, mean 77.7 +/- 9.8 years) that were prepared for this study. The bony canal structure of the inner surface of the maxilla was clearly apparent in our results, and the bony canals were classified into three types according to the structure along the course of the PSAA: canal-like, ditch-shaped tunnel and fragmented, and the lest sides were undefined. Calcitonin gene-related peptide (CGRP)-positive fibers were identified along the PSAA in the bony canal of the maxilla by immunohistochemistry. The presence of the bony structure and CGRP-positive nerve fibers along the PSAA suggests that there is risk to the PSAA during surgery involving graft implant in the floor of the maxillary sinus.