Accuracy of semi-occlusive CAD/CAM titanium mesh using the reverse guided bone regeneration digital protocol: A preliminary clinical study.

PURPOSE: The reverse guided bone regeneration protocol is a digital workflow that has been introduced to reduce the complexity of guided bone regeneration and promote prosthetically guided bone reconstruction with a view to achieving optimal implant placement and prosthetic finalisation. The aim of the present study was to investigate the accuracy of this digital protocol. MATERIALS AND METHODS: Sixteen patients with partial edentulism in the maxilla or mandible and with vertical or horizontal bone defects were treated using the reverse guided bone regeneration protocol to achieve fixed implant rehabilitations. For each patient, a digital wax-up of the future rehabilitation was created and implant planning was carried out, then the necessary bone reconstruction was simulated virtually and the CAD/CAM titanium mesh was designed and used to perform guided bone regeneration. The computed tomography datasets from before and after guided bone regeneration were converted into 3D models and aligned digitally. The actual position of the mesh was compared to the virtual position to assess the accuracy of the digital project. Surgical and healing complications were also recorded. A descriptive analysis was conducted and a one-sample t test and Wilcoxon test were utilised to assess the statistical significance of the accuracy. The level of significance was set at 0.05. RESULTS: A total of 16 patients with 16 treated sites were enrolled. Comparing the virtually planned mesh position with the actual position, an overall mean discrepancy between the two of 0.487 ± 0.218 mm was achieved. No statistically significant difference was observed when comparing this to a predefined minimum tolerance (P = 0.06). No surgical complications occurred, but two healing complications were recorded (12.5%). CONCLUSION: Within the limitations of the present study, the reverse guided bone regeneration digital protocol seems to be able to achieve good accuracy in reproducing the content of the virtual plan. Nevertheless, further clinical comparative studies are required to confirm these results.

A new impression reference technique to simplify the digital workflow for immediate loading zygomatic implant-supported rehabilitation.

Zygomatic implant-supported rehabilitation has grown in popularity for use in clinical practice. Although many studies have been carried out into the surgical procedure, the prosthetic workflow is not clearly defined and standard techniques are not readily applied; thus, a digital approach may ultimately streamline the procedure. In the present study, the authors examined a digital workflow for immediately loaded prostheses supported by zygomatic implants. The novel technique proposed by the present authors, involving use of an impression reference, achieved promising results in terms of accuracy and procedural simplification.

Semi-occlusive CAD/CAM titanium mesh for guided bone regeneration: Preliminary clinical and histological results.

PURPOSE: Guided bone regeneration is a widely used technique for the treatment of atrophic arches. A broad range of devices have been employed to achieve bone regeneration. The present study aimed to investigate the clinical and histological findings for a new titanium CAD/CAM device for guided bone regeneration, namely semi-occlusive titanium mesh. MATERIALS AND METHODS: Nine partially edentulous patients with vertical and/or horizontal bone defects underwent a guided bone regeneration procedure to enable implant placement. The device used as a barrier was a semi-occlusive CAD/CAM titanium mesh with a laser sintered microperforated scaffold with a pore size of 0.3 mm, grafted with autogenous and xenogeneic bone in a ratio of 80:20. Eight months after guided bone regeneration, surgical and healing complications were evaluated and histological analyses of the regenerated bone were performed. RESULTS: A total of 9 patients with 11 treated sites were enrolled. Two healing complications were recorded: one late exposure of the device and one early infection (18.18%). At 8 months, well-structured new regenerated trabecular bone with marrow spaces was mostly present. The percentage of newly formed bone was 30.37% ± 4.64%, that of marrow spaces was 56.43% ± 4.62%, that of residual xenogeneic material was 12.16% ± 0.49% and that of residual autogenous bone chips was 1.02% ± 0.14%. CONCLUSION: Within the limitations of the present study, the results show that semi-occlusive titanium mesh could be used for vertical and horizontal ridge augmentation. Nevertheless, further follow-ups and clinical and histological studies are required.

The Curved Presplitting Technique in a Totally Edentulous Atrophic Mandible: A Surgical Case Report.

The management of horizontally fully edentulous atrophic ridges is a common problem in dental implantology. This case report describes an alternative modified two-stage presplitting technique. The patient was referred for an implant-supported rehabilitation of their edentulous mandible. CBCT scans showed a mean available bone width of about 3 mm. At the first stage, four linear corticotomies were performed using a piezoelectric surgical device. At the second surgical stage 4 weeks later, bone expansion was performed, and four implants were placed in the interforaminal area. The healing process was uneventful. No fractures of the buccal wall and no neurologic lesions were observed. Postoperative CBCT scans showed a mean bone width gain of about 3.7 mm. Implants were uncovered 6 months after the second surgery, and 1 month later, a fixed provisional screw-retained prosthesis was delivered. This approach could be used as a reconstructive technique that avoids using grafts and reduces treatment times, possible complications, postsurgical morbidity, and costs by exploiting the patient's native bone as much as possible. Considering the limitations of a case report, randomized controlled clinical trials are needed to confirm the results and validate this technique.

Influence of Keratinized Tissue on Short Dental Implants: A Parallel Cohort Retrospective Study on 217 Implants with a Mean Follow-up of 4.1 Years.

PURPOSE: To assess whether the presence or absence of keratinized tissue height (KTh) may have an influence on marginal bone levels, complications, and implant survival for short implants. MATERIALS AND METHODS: The study was designed as parallel cohort retrospective research. Short implants with an implant length < 7 mm were considered. One cohort was composed of patients with short implants surrounded by ≥ 2 mm of KTh (adequate KTh); the other cohort included implants with < 2 mm of KTh (not-adequate KTh). Outcome measures were marginal bone level (MBL) changes, failures, and complications. RESULTS: One hundred ten patients treated with 217 short and extrashort implants (4 to 6.6 mm long) were retrospectively included. The mean follow-up was 4.1 years after prosthetic loading (range: 1 to 8 years). The differences between KTh groups in MBL were not statistically significant at every follow-up considered: 0.05 mm at 1 year (P = .48), 0.06 mm at 3 years (P = .34), 0.04 mm at 5 years (P = .64), and 0.03 at 8 years (P = .82). A total of nine complications were reported: three in the not-adequate KTh group and six in the adequate group; the difference was not statistically significant (OR: 3.03, 95% CI: 0.68 to 13.46, P = .14). Five implants failed due to peri-implantitis, two in the not-adequate KTh group and three in the adequate group, without a statistically significant difference (OR: 2.76, 95% CI: 0.42-17.99, P = .29). CONCLUSION: This study showed no statistically significant differences in MBL, complications, and implant failure rates between short implants with adequate or not-adequate KThs. However, given the importance of patient comfort while brushing and plaque accumulation, keratinized tissue grafts could be important in selected patients, especially for those who are severely atrophic, also taking into consideration all the limitations of this study and the mediumterm follow-up. Nevertheless, longer follow-ups, larger numbers of patients, and randomized controlled clinical trials are needed before making more reliable clinical recommendations. Int J Oral Maxillofac Implants 2023;38:462-467. doi: 10.11607/jomi.9918.

Extra-short (4-mm) implants placed after regenerative failures in the posterior atrophic mandible: A retrospective study.

PURPOSE: To explore whether extra-short (4-mm) implants could be used to rehabilitate sites where regenerative procedures had failed in order to avoid additional bone grafting. MATERIALS AND METHODS: A retrospective study was conducted among patients who had received extra-short implants after failed regenerative procedures in the posterior atrophic mandible. The research outcomes were complications, implant failure and peri-implant marginal bone loss. RESULTS: The study population was composed of 35 patients with 103 extra-short implants placed after the failure of different reconstructive approaches. The mean follow-up duration was 41.3 ± 21.4 months post-loading. Two implants failed, leading to a failure rate of 1.94% (95% confidence interval 0.24%-6.84%) and an implant survival rate of 98.06%. The mean amount of marginal bone loss at 5 years post-loading was 0.32 ± 0.32 mm. It was significantly lower in extra-short implants placed in regenerative sites that had previously received a loaded long implant (P = 0.004). Failure of guided bone regeneration before placement of short implants tended to lead to the highest annual rate of marginal bone loss (P = 0.089). The overall rate of biological and prosthetic complications was 6.79% (95% confidence interval 1.94%-11.70%) and 3.88% (95% confidence interval 1.07%-9.65%), respectively. The success rate was 86.4% (95% confidence interval 65.10%-97.10%) after 5 years of loading. CONCLUSIONS: Within the limitations of this study, extra-short implants seem to be a good clinical option to manage reconstructive surgical failures, reducing surgical invasiveness and rehabilitation time.

Simultaneous GBR and Implant Placement with Resorbable Membranes in the Rehabilitation of Partially Edentulous and Horizontally Atrophic Dental Arches: A Retrospective Study on 97 Implants with a 3- to 7-Year Follow-up.

This retrospective study evaluates the clinical and radiographic outcomes of simultaneous guided bone regeneration (GBR) and implant placement procedures in the rehabilitation of partially edentulous and horizontally atrophic dental arches using resorbable membranes. A total of 49 patients were included, and 97 implants were placed. Patients were followed up for 3 to 7 years after loading. The data indicate that GBR with simultaneous implant placement and resorbable membranes can be a good clinical choice, and the data suggest that it could be better to horizontally reconstruct no more than 3 mm of bone in order to reduce the number of complications and to obtain stable results. However, this technique remains difficult and requires expert surgeons.

A 5-year randomized controlled clinical trial comparing 4-mm ultrashort to longer implants placed in regenerated bone in the posterior atrophic jaw.

BACKGROUND: Short implants (up to 5-mm long) have shown good results when compared to longer implants placed in augmented bone. PURPOSE: To evaluate if 4-mm ultrashort implants could also be an alternative to bone augmentation in the severely atrophic posterior jaws. The primary aim of the study was to compare implant survival rates between study groups. MATERIALS AND METHODS: Eighty partially edentulous patients with posterior atrophic jaws (5-6 mm of bone above the mandibular canal and 4-5 mm below the maxillary sinus) were included: 40 patients in the maxilla and 40 in mandible. The patients were randomized to receive one to three 4-mm ultrashort implants or one to three implants at least 10-mm long in augmented bone. Results are reported 5 years after loading with the following outcome measures: implant and prosthetic failures, complications and peri-implant marginal bone level changes. RESULTS: Thirty-two complications were reported for the control group in 18 patients versus 13 complications in 10 patients in the test group, the difference being not statistically significant (p = 0.103). In the augmented group, 12 implants failed in 6 patients versus 7 short implants in 6 cases, and 9 prostheses failed in the control group while 4 in the test one, without statistically significant differences (p = 1.000 and 0.363, respectively). At 5 years after loading, short implants lost on average 0.58 ± 0.40 mm of peri-implant marginal bone and long implants 0.99 ± 0.58 mm, the difference was statistically significant (p = 0.006). CONCLUSION: Four-millimeter ultrashort implants showed similar if not better results when compared to longer implants placed in augmented jaws 5 years after loading. For this reason, their use could be in specific cases preferable to bone augmentation since the treatment is less invasive, faster, cheaper and associated with less morbidity. However, longer follow-ups and larger trials are needed.

An Ancient Science to Improve Today's Clinical Practice: Oral Surgery Meets Human Anatomy.

Human body dissection was a ubiquitous practice in the past, to better understand anatomy and to develop medicine. Today, its role could still be important to answer everyday clinical queries and help surgeons. The example of the possible lack of anesthesia during symphysis surgeries can emphasize the usefulness of dissection. The mandibular symphysis usually receives innervation from inferior alveolar nerve terminations, but, in some rare cases, a particular anastomosis involves the lingual nerve and the nerve to the mylohyoid. The anatomical knowledge resulting from body dissections could help oral surgeons to understand the reason why the patient could feel pain during the surgery, and ensure performance of the right lingual nerve block to obtain complete anesthesia. This clinical situation shows the educational role of an ancient, yet still valid, practice, human dissection, and the importance of anatomical studies to improve surgical skills, to provide better treatment for the patient.

Dynamic Navigated "Sandwich" Technique: A Novel Surgical Approach for Safe Osteotomies in the Rehabilitation of an Atrophic Posterior Mandible: A Case Report.

A 56-year-old female patient with vertical atrophy of the right posterior mandible was treated adopting an interpositional bone block approach using a cancellous heterologous bone block. Osteotomies of the patient's mandible were performed with the help of dynamic computer-assisted surgery using virtual anatomical patient information obtained from a cone beam computed tomography (CBCT). The use of the dynamic computer-assisted surgery allowed authors to perform the horizontal osteotomy line as planned preoperatively on the CBCT virtual reconstruction, trying to minimize the risks of the inlay technique. No neurological complications were observed after surgery. The inlay technique could benefit from the aid of dynamic navigation technologies in posterior atrophic mandibles, increasing the reproducibility of the technique. A likely safer method for performing osteotomies with the "sandwich" technique in the posterior atrophic mandible is reported.

Decision Criteria Proposed for the Treatment of Vertical Bone Atrophies in the Posterior Mandible.

In everyday practice, surgeons have to deal with bone atrophy. These rehabilitations are even more complex in the posterior mandible, and it is still unclear in the literature which fixed rehabilitation option is best. The purpose of this article was to help oral surgeons to choose the proper and updated treatment for their atrophic patients. Posterior mandible bone atrophies were divided into four main groups depending on the bone height measured above the inferior alveolar nerve: (1) ≤ 4 mm; (2) > 4 mm ≤ 5 mm; (3) > 5 mm ≤ 6 mm; (4) > 6 mm < 7 mm. Different approaches were proposed for each group, considering patient expectations. If ≤ 4 mm of bone height was available, guided bone regeneration was used as the adequate approach. For bone heights > 4 mm and ≤ 6 mm, the "sandwich" technique and/or short implants were used, depending on esthetics. In cases with > 6 mm and < 7 mm above the mandibular canal, short implants might be the proper option. The authors' clinical experience and the literature were considered in order to suggest a possible correct treatment decision based on the residual bone height in the posterior mandible.

Minimally Invasive Fixed Rehabilitation of an Extremely Atrophic Posterior Mandible Using 4-mm Ultrashort Implants: A Case Report with a 7-Year Follow-up.

This case report describes the rehabilitation of an extremely atrophic posterior mandible using 4-mm ultrashort implants and reports clinical and radiographic outcomes 7 years after loading. The patient refused to undergo any other treatment, from the removable prosthesis to the reconstructive surgery, and asked for a fixed, minimally invasive solution in the shortest possible time. The residual bone height above the alveolar nerve was an average of about 5 mm, so it was decided to treat the patient with four 4-mm ultrashort implants. Within the limitations of this case report, this procedure appears successful at 7 years after loading in this specific case and could reduce invasiveness, rehabilitative times, and costs. However, longer follow-ups on a large number of patients coming from randomized controlled clinical trials are necessary before making more reliable recommendations.