Is flapless implant surgery a viable option in posterior maxilla? A review

Conventional avulsion versus less traumatic extraction of ankylosed roots with a magnetoelectric device in anterior maxillary areas

The analysis aimed to compare two different single-tooth extraction surgical approaches in anterior maxillary areas of the ankylosed teeth: less traumatic magneto-electrical (mag) versus conventional tooth extraction (con) in minimizing the adverse effects on post-extractive sockets. Parameters of clinical interest such as intra-surgical fracture of the buccal bone plate, presence of postoperative inflammation, and application of stitches were acquired from medical records. The data were subjected to Pearson's χ2 analysis or to Fisher's exact test with significance at 0.05. Sixty-six hopeless maxillary permanent ankylotic teeth were extracted in the same number of patients. In the mag group 2 incisors suffered a fracture. Two patients out of 40 had signs and symptoms of inflammation that resolved completely within 3 days. In the con group 18 out of 26 patients suffered from buccal alveolar fracture. Six of these patients experienced signs of inflamed tissue. The two groups showed significant differences with p-values ≤0.0009 with regards to fracture (2/38 vs. 18/8) and tissue inflammation variables (2/38 vs. 10/16). A significantly different distribution about the presence of sutures was registered between the mag (4/36) and the con (18/8) group with a p-value <0.0001. Mag group seemed to have reduced frequency of fractured and infected post-extractive sites.

Healing of Peri-Implant Tissue following Flapless Implant Surgery

Background

Flapless surgery for implant placement has been gaining popularity among implant surgeons. it has numerous advantages, including preservation of circulation, decreased surgical time; improved patient comfort; and accelerated recuperation.

Materials and Methods

As a part of the study to evaluate crestal bone loss changes after placement of implant using the flapless technique, we placed twenty endosseous implants. Access was achieved to the crestal bone using a tissue punch. Clinical and radiographic analyses were performed second and fourth months after placement of the implant. Postoperative pain was measured by the visual analog scale at the 4th, 8th, and 24th hour.

Results

The findings of the present study demonstrate that the average crestal bone loss around the implant at 4 months using the flapless technique was 0.19 mm. No implants failed to osseointegrate, and no implants exhibited bone loss greater than 0.5 mm in the first four months. This present study shows significantly less postoperative pain in the flapless technique of implant placement.

Conclusion

The flapless approach is a predictable procedure when patient selection and surgical technique are appropriate.

Analysis of Linear and Angular Deviations of Implants Installed With a Tomographic-Guided Surgery Technique: A Prospective Cohort Study

The aim of this study was to evaluate the linear and angular deviations of the implants installed by the computerized tomography (CT)-guided surgery technique. Eighteen patients who underwent implant insertion by means of CT-guided surgery participated in this study. Ten of these patients had a fully edentulous maxilla, and 8 had a fully edentulous mandible. The patients received a total of 115 implants, of which 81 implants were installed in the maxilla and 34 installed in the mandible. Tomographic guides were made for tomographic examination in both the upper and lower jaws. After the image acquisition, the virtual planning of the positioning of the implants was performed in relation to the previously made prosthesis. The measurement of the linear and angular deviations between the virtual planning and the final position of the implants was performed with the overlap of the planning and postoperative tomography. There were no differences in the linear and angular deviations of the implants installed in the maxilla and mandible. Compared with the coronal region, there was a trend of greater linear deviations in the apical regions of the implants and a greater tendency toward deviations in the posterior regions than in the anterior regions of both arches. The CT-guided surgery promoted the installation of implants with high accuracy and allowed the installation of straight pillars in all cases evaluated. The linear deviations were not different in the different regions of the mouth or in the different portions of the implants.

Marginal Bone Loss in Implants Placed in the Maxillary Sinus Grafted With Anorganic Bovine Bone: A Prospective Clinical and Radiographic Study

BACKGROUND

Sinus elevation is a reliable and often-used technique. Success of implants placed in such situations, even with bone substitutes alone, prompted the authors of this study to strive for bone loss close to zero and research variables that cause higher or lower rates of resorption. The objective of this study is to evaluate survival rates and marginal bone loss (MBL) around implants placed in sites treated with maxillary sinus augmentation using anorganic bovine bone (ABB), and identify surgical and prosthetic prognostic variables.

METHODS

Fifty-five implants were placed in 30 grafted maxillary sinuses in 24 patients. Periapical radiographs were evaluated immediately after implant placement (baseline), 6 months, and at the most recent follow-up. MBL was calculated from the difference between initial and final measurements, taking into account a distortion rate for each radiograph compared with original implant measurements.

RESULTS

Survival rate was 98.2%, with only one implant lost (100% survival rate after loading) over a mean follow-up time of 2.0 ± 0.9 years. MBL ranged from 0 to 2.85 mm: 75.9% of mesial sites and 83.4% of distal sites showed <1 mm of MBL, whereas 35.2% of mesial sites and 37% of distal sites exhibited no bone loss. MBL was significantly (P <0.05) greater in open-flap compared with flapless surgery.

CONCLUSIONS

Within the limitations of the present study, it was concluded that maxillary sinus elevation with 100% ABB gives predictable results, and that flapless surgery results in less MBL compared with traditional open-flap surgery.

Flapless Versus Traditional Dental Implant Surgery: Long-Term Evaluation of Crestal Bone Resorption

PURPOSE

The literature reports that flapless compared with traditional implant surgery can be associated with several advantages, including the maintenance of peri-implant hard tissues. This study investigated vertical bone resorption during long-term follow-up after implant placement with flapless versus traditional surgery.

MATERIAL AND METHODS

In this prospective, randomized controlled clinical trial, 40 patients underwent implant placement at the Maxillofacial Department Surgery of the Istituto Stomatologico Italiano Hospital in Milan, Italy. Patients were randomly assigned to the control or experimental group. The control group had implants placed with open flap surgery (traditional surgery), whereas the experimental group had implants placed with flapless surgery. The distance between the first implant thread and the marginal crestal bone level was measured at the basal, loading, and long-term control points. The basal recording was performed just after implant placement. The loading measurement was recorded at the time of implant loading, after 2 months of healing for the lower jaw and after 3 months of healing for the upper jaw, and the long-term control record was registered 36 months after implant placement. Statistical analysis was performed using mean values and standard deviations based on bone resorption in the 2 groups. To detect statistical differences, the Student t test was applied. Differences were considered significant if P values were less than .05.

RESULTS

The control group (open flap surgery) was comprised of 19 patients, and the experimental group (flapless surgery) was comprised of 21 patients. No statistical differences were found in peri-implant bone resorption between the 2 groups at the basal, implant loading, and 3-year control recordings.

CONCLUSION

According to this study, the approach to implant surgery does not seem to influence peri-implant bone resorption in humans, at least for the period measured in this study.

Association between implant apex and sinus floor in posterior maxilla dental implantation: A three-dimensional finite element analysis

The aim of the present study was to evaluate the effect of the association between the implant apex and the sinus floor in posterior maxilla dental implantation by means of three-dimensional (3D) finite element (FE) analysis. Ten 3D FE models of a posterior maxillary region with a sinus membrane and different heights of alveolar ridge with different thicknesses of sinus floor cortical bone were constructed according to anatomical data of the sinus area. Six models were constructed with the same thickness of crestal cortical bone and a 1-mm thick sinus floor cortical bone, but differing heights of alveolar ridge (between 10 and 14 mm). The four models of the second group were similar (11-mm-high alveolar ridge and 1-mm-thick crestal cortical bone) but with a changing thickness of sinus floor cortical bone (between 0.5 and 2.0 mm). The standard implant model based on the Nobel Biocare^® implant system was created by computer-aided design (CAD) software and assembled into the models. The materials were assumed to be isotropic and linearly elastic. An inclined force of 129 N was applied. The maximum von Mises stress, stress distribution, implant displacement and resonance frequencies were calculated using CAD software. The von Mises stress was concentrated on the surface of the crestal cortical bone around the implant neck with the exception of that for the bicortical implantation. For immediate loading, when the implant apex broke into or through the sinus cortical bone, the maximum displacements of the implant, particularly at the implant apex, were smaller than those in the other groups. With increasing depth of the implant apex in the sinus floor cortical bone, the maximum displacements decreased and the implant axial resonance frequencies presented a linear upward tendency, but buccolingual resonance frequencies were hardly affected. This FE study on the association between implant apex and sinus floor showed that having the implant apex in contact with, piercing or breaking through the sinus floor cortical bone benefited the implant stability, particularly for immediate loading.

Outcomes of implants placed with three different flapless surgical procedures: a systematic review

The aim of this systematic review was to evaluate the outcomes of flapless surgery for implants placed using either free-hand or guided (with or without 3D navigation) surgical methods. Literature searches were conducted to collect information on survival rate, marginal bone loss, and complications of implants placed with such surgeries. Twenty-three clinical studies with a minimum of 1 year follow-up time were finally selected and reviewed. Free-hand flapless surgery demonstrated survival rates between 98.3% and 100% and mean marginal bone loss between 0.09 and 1.40 mm at 1-4 years after implant insertion. Flapless guided surgery without 3D navigation showed survival rates between 91% and 100% and mean marginal bone loss of 0.89 mm after an observation period of 2-10 years. The survival rates and mean marginal bone loss for implants placed with 3D guided flapless surgery were 89-100% and 0.55-2.6mm, respectively, at 1-5 years after implant insertion. In 17 studies, surgical and technical complications such as bone perforation, fracture of the surgical guide, and fracture of the provisional prosthesis were reported. However, none of the identified methods has demonstrated advantages over the others. Further studies are needed to confirm the predictability and effectiveness of 3D navigation techniques.

The effect of flapless surgery on implant survival and marginal bone level: a systematic review and meta-analysis

BACKGROUND

The clinical outcomes of implants placed using the flapless approach have not yet been systematically investigated. Hence, the present systematic review and meta-analysis aims to study the effect of the flapless technique on implant survival rates (SRs) and marginal bone levels (MBLs) compared with the conventional flap approach.

METHODS

An electronic search of five databases (from 1990 to March 2013), including PubMed, Ovid (MEDLINE), EMBASE, Web of Science, and Cochrane Central, and a hand search of peer-reviewed journals for relevant articles were performed. Human clinical trials with data on comparison of SR and changes in MBL between the flapless and conventional flap procedures, with at least five implants in each study group and a follow-up period of at least 6 months, were included.

RESULTS

Twelve studies, including seven randomized controlled trials (RCTs), one cohort study, one pilot study, and three retrospective case-controlled trials (CCTs), were included. The SR of each study was recorded, weighted mean difference (WMD) and confidence interval (CI) were calculated, and meta-analyses were performed for changes in MBL. The average SR is 97.0% (range, 90% to 100%) for the flapless procedure and 98.6% (range, 91.67% to 100%) for the flap procedure. Meta-analysis for the comparison of SR among selected studies presented a similar outcome (risk ratio = 0.99, 95% CI = 0.97 to 1.01, P = 0.30) for both interventions. Mean differences of MBL were retrieved from five RCTs and two retrospective CCTs and subsequently pooled into meta-analyses; however, none of the comparisons showed statistical significance. For RCTs, the WMD was 0.07, with a 95% CI of -0.05 to 0.20 (P = 0.26). For retrospective CCTs, the WMD was 0.23, with a 95% CI of -0.58 to 1.05 (P = 0.58). For the combined analysis, the WMD was 0.03, with a 95% CI of -0.11 to 0.18 (P = 0.67). The comparison of SR presented a low to moderate heterogeneity, but MBL presented a considerable heterogeneity among studies.

CONCLUSION

This systematic review revealed that the SRs and radiographic marginal bone loss of flapless intervention were comparable with the flap surgery approach.