Long-term stable vertical bone regeneration after sinus floor elevation and simultaneous implant placement with and without grafting

Endo-sinus bone gain following osteotome-mediated sinus floor elevation with Bio-Oss Collagen compared with no grafting material: a one-year single-blind randomized controlled trial

The objective of this study was to assess endo-sinus bone gain (ESBG) following osteotome-mediated sinus floor elevation with Bio-Oss Collagen (test) compared with no grafting material (control) using two- and three-dimensional radiographic methods, as part of a randomized controlled trial (ClinicalTrials.gov, NCT04618900). Forty healthy patients who met the necessary eligibility criteria were allocated by block randomization to either the test group (20 patients) or control group (20 patients). Cone beam computed tomography scans were obtained at enrolment (T0), immediately after surgery (T1), at delivery of the prosthetic rehabilitation (T2), and 1 year after functional implant loading (T3). Mean differences were expressed with the 95% confidence interval; significance was set at P < 0.05. ESBG was significantly increased with Bio-Oss Collagen compared with no grafting material at T1, T2, and T3 (P < 0.001). A gradual decrease in ESBG was observed over time with both treatment modalities (P < 0.001), which diminished the difference between the test and control groups at T2 and T3. ESBG was observed to be positively correlated with implant protrusion length and negatively correlated with the residual bone height. In osteotome-mediated sinus floor elevation, the application of Bio-Oss Collagen underneath the elevated Schneiderian membrane improved ESBG significantly when compared with no grafting material. However, the increased ESBG seems not to have positively improved the treatment outcomes in terms of the implant stability quotient or the survival of the implants or suprastructures.

Primary stability of different implant macrodesigns in a sinus floor elevation simulated model: an ex vivo study

BACKGROUND

A novel type of implant (Straumann® BLX implant) has been developed for certain stability from the mechanical and biological aspects and is expected for the implant placement in atrophic maxilla with sinus floor elevation (SFE).

PURPOSE

The aim of this study was to evaluate the primary stability in the implants with different macrodesigns in an SFE simulated model. Primary stabilities defined as maximum insertion torque (MIT) and implant stability quotient (ISQ) were compared between this novel type of implant and other types.

MATERIALS AND METHODS

Five types of Straumann® 10 mm length implants (Standard Plus; SP, Tapered Effect; TE, Bone Level; BL, Bone Level Tapered; BLT and BLX) and two types of Straumann® 6 mm length implants (SP short, BLX short) were used in this study. Each implant was inserted through 5 mm-thick porcine iliac crest blocks (an SFE simulated model). Primary stability was evaluated by using MIT and ISQ.

RESULTS

The mean value of MIT for BLX group showed significantly higher values than SP, BL (p < 0.01), and TE (p < 0.05) groups. The mean value of ISQ for BLX group was significantly higher than the other groups (p < 0.01). The mean value of MIT and ISQ for BLX and BLX short group were significantly higher than those for SP and SP short group (p < 0.01).

CONCLUSIONS

In an SFE simulated ex vivo model, BLX group showed the highest values. These results suggest that implant selection can play a crucial role in the achievement of primary stability during SFE and simultaneous implant placement.

Prediction of Residual Alveolar Bone Height in the Posterior Maxilla After Dental Extractions

PURPOSE

After tooth extraction in the posterior maxilla, bone resorption often limits implant placement unless additional grafting procedures are performed. However, it is difficult to predict the amount of bone that will remain after extraction based on current evidence. The purpose of this study was to develop a method for predicting the postextraction alveolar bone height in the posterior maxilla.

PATIENTS AND METHODS

The authors conducted a retrospective cohort study that included all patients who were treated for the extraction and replacement of a maxillary first molar with a dental implant from 2008 to 2019. Potential predictor variables included thirteen pre-extraction radiographic measurements obtained via cone-beam computed tomography. The outcome variable was having more than 6 mm of bone height from the alveolar crest to the sinus floor after extraction. Decision tree analyses were used to search for the best predictors of this outcome using random forest analysis with a maximum of 3 randomly chosen covariates in each candidate tree.

RESULTS

A total of 63 patients were included in the study; 55.6% were women, and the mean age was 57.6 ± 14.5 years. In this study population, having a bone height from the furcation to the maxillary sinus floor of <6.7 mm had a 7.1% chance of having >6 mm of bone height postoperatively, whereas those patients with ≥6.7 mm at the same position preoperatively had a 61.9% chance of having >6 mm of bone height postoperatively (P < .001).

CONCLUSIONS

This study suggests that patients with <6.7 mm of bone from the furcation to the sinus are at increased risk of having insufficient bone to support a dental implant without additional grafting at the maxillary first molar position. When treating these patients, the surgeon should consider performing a procedure at the time of extraction to increase bone height or explain additional bone grafting is expected for ideal implant placement.

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

ABSTRACT

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

Sinus Floor Elevation via an Osteotome Technique without Biomaterials

According to classic Hirschfeld studies, the first teeth to be lost are the first and second maxillary molars. After the teeth are extracted and the alveolar process is developed, the maxillary sinus is reabsorbed and pneumatized with a decrease in bone availability in the posterior sector of the maxilla. This process often creates the need to perform regeneration techniques for the placement of implants in this area due to the low availability of bone. The most frequently used and documented technique for the elevation of the sinus maxillary floor is elevation by the side window, as proposed by Tatum. In 1994, Summers proposed a technique that allowed the elevation of the sinus floor from a crestal access using an instrument called an osteotome, as well as the placement of the implant in the same surgical act. The aimed of the study was to evaluate the survival of 32 implants placed in posterior maxilla with bone availability less than 5 mm performing a sinus lift augmentation technique with osteotome without biomaterials. The results of this study show a survival rate of 100% for 32 implants placed in situations with an initial bone availability of 2 to 5 mm without the use of graft material. The infra-drilling technique used offers an increase in the primary stability of implants that allows adequate osteointegration Implants placed were charged at 12 weeks. In all cases, spontaneous bone formation was observed, even in cases where a positive Valsalva maneuver was observed. This proposed technique reduces treatment time and the need for more invasive maxillary sinus augmentation techniques.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Background

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

Methods

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

Results

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

Conclusions

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

Facial cortical bone regeneration post-extraction in non-grafted sockets allows for early implant placement and long-term functional stability

OBJECTIVE

To evaluate posterior implant placement feasibility shortly after tooth extraction in non-grafted sockets with and without dehiscence at the time of extraction.

DESIGN

Ninety-five patients requiring posterior extractions entered this cross-sectional study. They were divided in three groups after extraction: G1 without dehiscence, G2 with dehiscence ≤5 and G3 > 5 mm. CBCT were taken prior to implant placement at an average of 12-weeks post-extraction to evaluate the need for grafting, cortical bone formation and bucco-lingual width (BLW). Actual BLW (n = 60) were compared to minimum expected BLW in 3 scenarios of BLW thickness averaging 6.4-7.4-8.4 mm. Peri-implant tissues were assessed for pocket formation and inflammation following established success criteria.

RESULTS

New cortical bone formation and sufficient BLW made implant placement feasible in sites with and without dehiscence at the time of extraction after an average healing time of 11.9 ± 2.4weeks (range: 8-18). Total average CBCT BLW was 10.1 ± 1.6 mm. All groups had a significantly higher BLW, than scenarios 1-3 (p < 0.0001). Molars were 20 times more likely than premolars to heal with BLW>10 mm (OR = 20; RR = 4.2; CI95 %: 5.3-74.2; p < 0.0001). Dehiscence sockets were 1.5 times more likely than non-dehiscenced sockets to present BLW ≤ 10 mm (OR = 1.5; RR = 0.6; CI95 %:0.9-2.5; p = 0.08). A band of keratinized tissue was present in all implants and success rates were 100 % at an average follow-up of 51.0 ± 23.4 months.

CONCLUSION

Implant placement is feasible without socket grafting shortly after tooth extraction. Non-grafted sockets present a significant osteogenic potential. Dehiscence sockets are likely to self-repair by forming a new cortical plate. The unassisted regenerated intra-socket bone allows for functional implant stability long-term.

A prospective study on ultra-wide diameter dental implants for immediate molar replacement

BACKGROUND

Although wide diameter implants are well documented, little is known about ultra-wide diameter implants (>6 mm). This study evaluates the clinical outcome of ultra-wide diameter implants, placed in molar extraction sockets.

MATERIALS AND METHODS

Ultra-wide diameter implants (7-9 mm) were placed immediately after molar extraction in a 1-stage protocol, without raising a flap or using any bone grafts. After 4 months, the implant was loaded with a single screw-retained crown. Bone loss was evaluated using peri-apical radiographs. Plaque and bleeding were recorded. Crown and papilla dimensions were measured and compared with the contra-lateral tooth.

RESULTS

Fifty-one patients (36 male and 15 female), mean ages 61 years old, were treated with 26 implants in the maxilla and 25 implants in the mandible. The majority had a thick (#19) or medium (#31) biotype. After a mean-follow-up period of 23 months, the mean bone level was located 1.16 mm apical of the implant-abutment junction (SD 0.42, range 0.00-2.45) while the actual bone remodeling associated with socket healing resulted in a mean coronal movement of the bone level of 0.15 mm. The mean insertion torque was 116 Ncm (SD 53, range 10-250). There were no differences in papilla height (P = .55), crown length (P = .32), zenith (P = .84), and bucco-palatal dimensions (P = .38). There was a significant difference in the mesio-distal dimension (P = .01). Mean probing depth was 2.59 mm at the implant and 2.23 mm at the contra-lateral tooth (P = .001). There was significantly more plaque at the tooth compared to the implant (P = .01), but there was no significant difference in terms of bleeding on probing (P = .08). Patient satisfaction was high with 72.5% of the patients experiencing no problems at all.

CONCLUSIONS

Ultra-wide diameter implants have a predictable outcome, demonstrating very little bone loss. Papilla and crown dimensions were comparable to the contra-lateral natural tooth.

Transalveolar sinus floor lift without bone grafting in atrophic maxilla: A meta-analysis

We performed a meta-analysis aimed to assess the clinical results after transalveolar sinus floor lift without bone grafting in the atrophic maxilla. A systematic electronic literature search was conducted in PubMed, Embase and The Cochrane Library, followed by a manual search. Two reviewers independently extracted study data and conducted quality assessments. Ten non-controlled studies including 1484 implants and eight controlled studies (5 RCTs and 3 prospective studies) including 817 implants (451 implants in the non-graft group) were enrolled in this study. The survival rate of implants via the graft-free method was 98% (95%CI 96% to 100%). There was no significant difference in the survival rate between the non-graft group and the graft group (RR: 1.02; p = 0.18). No statistically significant difference in marginal bone loss was detected between the groups at 12 months (0.57, p = 0.07) or 36 months (0.05, p = 0.61). The endo-sinus bone gain in the non-graft group was significantly lower than in the graft group at 12 months (−1.10, p = 0.0001) and 36 months (−0.74, p = 0.02). Hence, the available evidence suggests that predictable results could be acquired through transalveolar sinus floor lift without bone grafting, while there may be a trend toward more endo-sinus bone gain with bone grafts.