Atrophic Posterior Mandible Research Articles

Implant Stability and Marginal Bone Changes Associated with Different Staged Ridge-splitting Techniques Using Piezoelectric Surgery in Atrophic Posterior Mandible: A Comparative Study

Implant Stability and Marginal Bone Changes Associated with Different Staged Ridge-splitting Techniques Using Piezoelectric Surgery in Atrophic Posterior Mandible: A Comparative Study

Evaluation of buccolingual and linguobuccal implants in the atrophic posterior mandible: A finite element analysis study

AimThis study aims to evaluate the stress distribution on buccolingual and linguobuccal tilted implants in the atrophic posterior mandible using finite element analysis. Material and methodsTwelve digital models of implants with varying lengths (8.5 mm, 10 mm, 11.5 mm) and angles (20°, 25°) were created. These implants were analyzed under 150 N vertical and oblique forces to assess stress distribution on both implants and surrounding bone. ResultsLinguobuccal implants generally exhibited lower maximum principal stress in cortical bone, while buccolingual implants showed lower minimum principal stress. Longer implants reduced stress under oblique loading. ConclusionTilted implants, particularly using the linguobuccal method, are effective for stress distribution in the atrophic posterior mandible. Further research should explore varying implant diameters and multiple placements for optimization.

Comparison of Khoury's Bone Shell Technique vs Titanium-reinforced Polytetrafluoroethylene Membrane for 3D-bone Augmentation in Atrophic Posterior Mandible: A Randomized Clinical Trial.

This study was designed to compare between the use of Khoury's bone shell technique vs titanium-reinforced PTFE membrane for 3D-ridge augmentation of atrophic posterior mandible. Sixteen patients were equally and randomly assigned to either the Khoury or PTFE group. In Khoury group, a mandibular bone block was harvested, split and then fixed to augment the mandibular defect using osteosynthesis screws. In PTFE group, augmentation was achieved using Titanium-reinforced PTFE membranes fixed with bone tacks/screws. A mixture of autogenous and xenogenic graft material at a 1:1 ratio was used in both groups. Vertical and horizontal bone gain were obtained using cone-beam computed tomography (CBCT). Preoperative dimensions were compared with the final dimensions obtained 6 months postoperatively. No significant complications or neurosensory dysfunction were encountered. A solitary patient in the Khoury group experienced limited wound dehiscence, which was treated conservatively. For both groups, there were no significant differences between preoperative and postoperative vertical (p = 0.849 and 0.569) and horizontal (p = 0.778 and 0.367) dimensions. No significant differences exist between the augmentation dimension which can be obtained using either Khoury of Ti-PTFE membranes. Both approaches are delicate and necessitate surgical expertise and experience. Both techniques can be used to achieve predictable augmentation results with a low rate of complications. How to cite this article: Shaker AES, Salem AS, El-Farag SAA, et al. Comparison of Khoury's Bone Shell Technique vs Titanium-reinforced Polytetrafluoroethylene Membrane for 3D-bone Augmentation in Atrophic Posterior Mandible: A Randomized Clinical Trial. J Contemp Dent Pract 2024;25(6):518-526.

Evaluation of Guided Bone Regeneration Using Xenograft/APRF Mixture in Atrophic Posterior Mandible (Clinical and Radiographic Study)

Introduction: The rehabilitation of the posterior mandible with dental implants represents a hard challenge for clinicians today due to the lack of supporting bone. Different surgical techniques are currently being used to augment the posterior mandible, where GBR is considered the most commonly used. Materials and Methods: Fifteen patients were selected to treat mandibular alveolar ridge resorption with guided bone regeneration using a titanium-reinforced membrane and a filling mixture of xenograft bovine bone and PRF. The membrane was fixed using a Meisinger pin control kit and Profix 3mm microscrews. A PRF membrane was used to cover the Ti-d-ptfe.
 Results: Swelling, pain, and numbness were evaluated using the mixture of PRF/xenograft as well as PRF membranes. The results showed promising results in terms of primary wound healing, whereas a significant bone quantity with a mean bone volume of 5.78 ± 0.81 was reported after 6 months. The primary implant stability recorded high values and significantly increased at a period of 6 months post-insertion (p = 0.037). Conclusion: It could be concluded that the PFR/xenograft mixture can be promising when used with the titanium-reinforced d-ptfe membrane in 3D ridge reconstruction of the atrophic posterior mandible; moreover, using the PRF membrane to cover the TI-d-ptfe membrane could enhance soft tissue healing as well as prevent soft tissue dehiscence due to the concentration of growth factors that can be released during primary wound healing. The xenograft/PRf mixture can be consistently utilized for the creation of new bone in severely atrophic ridges if used in GBR. The high ISQ at primary implant placement and at a period of 6 months post-insertion, according to Osstell, can explain the successful application of this mixture in 3D bone augmentation of the atrophic posterior mandible.

Inferior alveolar nerve repositioning surgical techniques and outcomes – a systematic review

Inferior alveolar nerve (IAN) lateralization (IANL) or transposition (IANT) are both techniques allowing for dental implant placement in posterior atrophic mandibles. The aim of this study was to systematically review the implant survival rate and the complications associated with IAN reposition techniques with simultaneous implant placement in atrophic posterior mandibles.This systematic review was conducted following PRISMA guidelines (Preferred Reporting Items for Systematic review and Meta-Analysis). The review was designed to answer the following PICO question: Is IAN repositioning (I) a safe and efficient technique (O) to treat patient looking for fixed dental rehabilitation of an atrophic posterior mandible (P).Thirty-three articles were reviewed, including a total of 899 patients, and approximately 950 IAN repositioning procedures. Dental implant survival rate ranged between 86.95% and 100% with a mean dental survival rate of 90.16%. Among the 269 patients who underwent IANT, there were 93% immediate neurosensory disturbance, and 15% persistent neurosensory disturbance. Among the 350 patients who underwent IANL, there were 93% immediate neurosensory disturbance, and 6% persistent neurosensory disturbance.IANT and IANL are reliable techniques allowing safe dental implant placement in atrophic posterior mandible with high patient satisfaction. IANL seems to cause less persistent neurosensory disturbances compared to IANT. The level of evidence is poor due to the high number of bias present in the included studies. IAN neurosensory disturbance assessment should be better homogenized in order to increase comparability.

A Retrospective Study of Implant Placement Lateral to the Inferior Alveolar Nerve (ILIAN) in Severely Atrophic Posterior Mandibular Ridges

Currently, there are several techniques being used in the posterior mandible to increase alveolar bone height and width. However, each of these has potential complications and limitations. The purpose of the current study was to present the surgical technique and restorative considerations for implant placement lateral to the inferior alveolar nerve (IAN) in cases of severely atrophic edentulous posterior mandibles. In the current study, 26 implants in 16 patients were successfully placed lateral to IAN and restored with splinted screw-retained prostheses with a follow-up time after loading ranging from 3 months to 6 years. Two patients reported complications. One patient had a temporary paresthesia that resolved 3 months after implant placement and the second patient had minor paresthesia which was reduced after implant removal but remained in a small area on the left corner of her lip.

Buccally or Lingually Tilted Implants in the Lateral Atrophic Mandible: A Three-Year Follow-Up Study Focused on Neurosensory Impairment, Soft-Tissue-Related Impaction and Quality of Life Improvement.

Background and Objectives: In the severely resorbed posterior mandible, implant placement requires either bone regenerative procedures, subperiosteal implants or short implant placement with drawbacks including morbidity and increased treatment costs and duration. To overcome these inconveniences, some unconventional alternatives have been suggested, such as buccally or lingually tilted implants in the lateral mandible, bypassing the inferior alveolar nerve. The aim of the present retrospective study was to evaluate the three-year survival rate of implants inserted in the posterior atrophic mandible, bypassing the inferior alveolar nerve. The assessment was focused on the occurrence of postoperative complications related to neurosensory impairment and soft tissue impaction, as well as overall improvement in quality of life. Materials and Methods: Patients with severe bone atrophy in the lateral area of the mandible were included in the present study. Only the implants tilted either buccally or lingually to bypass the inferior alveolar nerve were analysed. The relation between peri-implant soft tissue and the healing abutment was assessed and a secondary revision surgery was performed when indicated. The Semmes-Weinstein pressure neurological test was used for qualitative assessment of inferior alveolar nerve function and the Geriatric Oral Health Assessment Index (GOHAI) was used for evaluating Oral-Health-Related Quality of Life (OHRQoL). Results: Fourteen implants were placed in nine patients during the evaluation period. Survival rate was 100%, temporary paraesthesia occurred in one patient and a limited definitive paraesthesia was seen in another patient. Mild or significant discomfort related to soft tissue impaction with healing abutment was observed in six out of nine patients. A statistically significant OHRQoL improvement was observed in all patients. Conclusions: Despite the limited number of patients and observation time, insertion of implants buccally or lingually bypassing the inferior alveolar nerve is a predictive treatment option for patients with severe bone atrophy in the posterior mandible.

Vertical ridge augmentation of atrophic posterior mandible with corticocancellous onlay symphysis graft versus sandwich technique: clinical and radiographic analysis.

Alveolar ridge augmentation of atrophic posterior mandibular ridge represents a challenge in oral and maxillofacial surgery to restore aesthetic and function. The aim of the study was to compare the clinical and radiographic outcomes of bone formation in atrophic posterior mandibles augmented using onlay symphysis cortico-cancellous bone block with that augmented using sandwich bone augmentation technique (Inlay). Twelve patients were selected with missing mandibular posterior teeth. CBCT were done for all patients preoperatively to assess the residual bone height, ranged between 5 and 7mm from the inferior alveolar nerve with adequate sufficient alveolar ridge width more than 4mm. Patients required bone augmentation procedure with autologous onlay chin graft (group I) versus those used as inlay sandwich technique (group II). Clinical and radiographic analysis were done to analyses the newly formed bone and bone height. Percent of change in bone height was also calculated and revealed that group I was higher than group II, however, statistically insignificant differences between the two groups were found regarding the percentage of newly formed bone. Vertical ridge augmentation procedures using onlay chin graft took lesser time than the interpositional grafting with fixation technique, however, both techniques are promising for vertical ridge augmentation.

Influence of different crown heights on shorter implants with different lengths, diameters, and designs at atrophic posterior mandible: A finite element analysis

Aim: The aim of the study is to compare the stresses cause of different crown heights on short implants with different lengths, diameters and designs under axial and oblique loads on the cortical bone and implant system using finite element analysis.
 Methodology: In the atrophic posterior mandible, 4 different implants of different sizes and designs were placed in the first molar region. Metal supported porcelain crowns with three different heights (10 mm, 12.5 mm, 15 mm) were designed on computer. Total of 12 study models were created. Axial and oblique loads were applied and by finite element analysis method Von Mises values in implant and abutment; maximum and minimum principal stress values in cortical bone were evaluated.
 Results
 Compared to axial load, significantly higher stress values were found at implant and cortical bone in obliquelly loaded models. As the length and diameter of the implant increased, the stresses on the cortical bone decreased. Compared to the threaded implant, the plateau design implant caused less stress on the bone under vertical loads, while causing more stress on the oblique.
 Unlike to the literature, it was observed that the stresses on the implant was higher in the larger diameter implant compared to the narrower.
 Conclusions
 As a result of the stress values obtained within the limits of the analysis, when the lengths of the crowns restored on short implants were compared, it was determined that the axial forces were at an acceptable level under all conditions.

Evaluation of the survival rate of short implants placed in the posterior atrophic mandible: 5-year clinical study.

The aim of the study was to assess the long-term prognosis of short implants (5 to 6 mm) placed in the posterior region of the atrophic mandible. The study included 81 patients with severe vertical atrophy of the bone in the posterior region. The patients had 248 short implants (5 to 6 mm) implants placed in the mandibular posterior region and 256 implants with length greater than 10 mm in the mandibular anterior region. Analysis of implant and prosthesis failures, cumulative survival rate, and marginal bone loss was determined at 1 year and 5 years of follow-up (58 ± 7 months). Mean marginal bone loss after 1 year of prosthetic loading was 0.74 mm for short implants and 0.72 mm for implants with length greater than 10 mm; after 5 years of prosthetic loading this was 1.27 mm for short implants and 1.31 mm for implants with length greater than 10 mm. Of 248 short implants (5 to 6 mm), six failed: four due to peri-implantitis and two due to lack of osseointegration (early rejection). Of 256 implants with length greater than 10 mm, five failed: three due to peri-implantitis and two due to lack of osseointegration (early rejection). On average, over the observation period (58 ± 7 months), the 5-year cumulative implant survival rate was 97.8% in short implants, and 98.1% in longer implants; the prosthesis cumulative survival rate was 98.2%. Based on the results, it was concluded that the prognosis of the use of short implants for prosthetics in the posterior resorbed mandible can be considered favorable and reasonable.

P-67954085-235 - A new classification of inferior alveolar nerve repositioning procedure for dental implants placement presentation and illustrative cases.

<h3>Objectives</h3> Tooth loss is one of the most common causes of reduced quality of life in adults. Recently there is an increasing global interest in treatments involving the Inferior Alveolar Nerve (IAN) repositioning for dental placement but standardization and classification of the techniques is warranted. In the present paper, a new classification is suggested, illustrated, and discussed. <h3>Patients and Methods</h3> A retrospective analysis of the preoperative radiographic records and the documents of the surgical procedures during a ten year period between 2008 -2018 of patients who had been treated with implant placement in conjunction with IAN repositioning of posterior atrophic mandible was performed. The cases were categorized according to the available bone, the nerve location, and the surgical intervention into four groups. <h3>Results</h3> Overall, 132 edentulous posterior mandibles in 98 patients (72 women, 26 men; age range 20-75 years) were included in the analysis. Those sites were divided into four categories: Category 1, included 54 patients with 72 sites, and was treated by one surgery. Category 2; included 15 patients with 15 sites and was treated with two stages. Category 3, included 17 patients with 21 sites, and category 4, included 12 patients with 24 sites. The treated 132 sites with IAN repositioning received 379 dental implants. All the sites were restored by an implant-supported fixed prosthesis. The patients reported good function and improvement in their quality of life. <h3>Conclusions</h3> This new classification might enhance diagnosis and help predict the treatment stages of the patients requiring IAN repositioning for dental implant placement.

Rehabilitation of Atrophic Posterior Mandible with Vertical Ridge Augmentation with Resorbable Membrane: Case Report with 3-Year Follow-up

Background: The placement of implants in the posterior mandible with the vertical bone defect can be associated with inadequate crown height space. Therefore, the vertical bone reconstruction of these defects is often necessary, although this procedure is technically challenging. Methods: A 49-year-old patient attended a private dental office for rehabilitation of an atrophic posterior mandible. The clinical and tomographic findings show absence of teeth #36, #37, #46, #47, and #48 with severe atrophy. Vertical bone augmentation was performed by using the guided bone regeneration technique with pericardium resorbable membrane followed by placement of short implants. The free gingival graft was performed, and after three months, screw-retained lithium disilicate single ceramic crowns were manufactured. Results: After a 3-years follow-up, bone loss around the implants or presence of gingival inflammation was not observed, and the prosthesis adaptation was found to have no alteration either. Therefore, aesthetics, as well as masticatory and speech functions, were preserved. Conclusion: There was no bone loss around the implants. The association between vertically guided bone regeneration using pericardium resorbable membrane is an alternative technique, and it avoids complications related to non-resorbable membrane exposure. It was shown to be viable after a 3-year follow-up.

Horizontal Bone Augmentation in the Posterior Atrophic Mandible and Dental Implant Stability Using the Tenting Screw Technique.

The aim of this study was to analyze horizontal bone augmentation using the tenting screw technique in the posterior mandible. Included subjects had a 3-mm bone width and 9-mm bone height, measured by CBCT. After the surgical approach, two to four screws were inserted, leaving 4 mm of extraosseous space; reconstruction was achieved using allogeneic biomaterial and leukocyte- and platelet-rich fibrin together with an absorbable membrane. After 4 months, a new CBCT scan was obtained to compare the bone gain and implant placement. Early and secondary stability were measured by the implant stability quotient (ISQ); prosthetic load was performed 16 weeks later. Student t test was used to compare bone gains and implant stability, with significance set at P < .05. Fourteen subjects and 27 surgical sites initially exhibited a mean bone width of 2.95 ± 0.75 mm. Four months after augmentation, the bone width was 7.15 ± 1.87 mm, confirming a significant bone gain (4.2 ± 1.26 mm). Twenty-seven implants were placed with a minimum insertion torque of 35 Ncm; the primary stability was 69.3 ± 7.16 ISQ, and the secondary stability was 75.9 ± 3.29 ISQ (P > .05). It may be concluded that the tenting screw technique is predictable in terms of bone gain and that it facilitates implant stability.

Atrofik Posterior Mandibular Kretlerde Farklı Boy Çap Açı ve Dizaynlarda Yerleştirilen İmplantlarda ve Çevre Kemikte Meydana Gelen Streslerin Sonlu Elemanlar Analizi ile Değerlendirilmesi

Atrofik Posterior Mandibular Kretlerde Farklı Boy Çap Açı ve Dizaynlarda Yerleştirilen İmplantlarda ve Çevre Kemikte Meydana Gelen Streslerin Sonlu Elemanlar Analizi ile Değerlendirilmesi

Passive medialization of the inferior alveolar nerve to facilitate implant placements in a patient with severe atrophic posterior mandible.

Placing implants in the edentulous jaw of an individual with severe posterior mandibular atrophy is challenging due to the insufficient bone height above the inferior alveolar nerve canal. The different reconstruction techniques available cause extensive morbidity, are costly, and require prolonged treatments. In here we report a case series of patients treated with a new minimally invasive technique to facilitate implant placement in patients with severely atrophied posterior mandible.

In-Block Lateralization as a New Technique for Mobilization of the Inferior Alveolar Nerve: A Technique Case Series.

The edentulous atrophic posterior mandible is often a great challenge for implant rehabilitation. Although a number of treatment options have been proposed, including the use of short implants and surgical grafting techniques, in cases of severe bone atrophy, techniques for mobilization of the inferior alveolar nerve (IAN) have been shown to be efficient, with good results. Four female patients underwent IAN lateralization for prosthetic rehabilitation of the posterior mandible from 2013 to 2019, with 3 years to 5 years and 3 months of follow-up. This case series describes a new technique for mobilization of the IAN, named in-block lateralization, to facilitate access to the IAN and to reduce nerve manipulation. The implant is immediately installed (allowing nerve lateralization in unitary spaces), and the original mandibular anatomy is restored with autogenous bone from the original bed during the same surgical procedure. When well indicated and well performed, this new approach provides better and easier visualization of the IAN and safer manipulation aiming to achieve good results for implant stability and minimal risk of neurosensory disturbances, allowing rehabilitation even in unitary spaces.

Sandwich osteotomy of the atrophic posterior mandible with interpositional autogenous bone block graft compared with bone substitute material: a systematic review and meta-analysis.

The objective of the present systematic review was to test the hypothesis that there were no differences in outcome of implant treatment after sandwich osteotomy in the atrophic posterior mandible with interpositional autogenous bone block graft, compared with bone substitute material. A MEDLINE/PubMed, Embase and Cochrane Library search in combination with hand-search of selected journals was conducted. Two short-term randomised controlled trials with a split-mouth study design and low risk of bias fulfilled the inclusion criteria. High survival rate of suprastructures and implants was disclosed with no significant difference between interpositional autogenous bone block graft compared with bone substitute material. Meta-analysis revealed patient-based implant survival risk ratio of 1.05 (95% CI: 0.88 to 1.25) and peri-implant marginal bone loss of 0.31mm (95% CI: -0.29 to 0.90) indicating no significant differences between the two treatments. High implant stability values, gain in vertical alveolar ridge height, bone formation, and few complications were reported with both treatments. Sandwich osteotomy with interpositional grafting material appears to be a predictable surgical technique for enhancement of the vertical alveolar ridge height in the atrophic posterior mandible prior to implant placement.

Modified Two-Stage Split Technique for Controlled Ridge Augmentation in Horizontally Atrophic Posterior Mandible: the First Stage of Research.

Various bone grafting methods are applied to eliminate horizontal atrophy of the jaws. However, problem complexity brings about ongoing research and development of new ways to achieve the predicted stable and long-term results of implantological treatment.The aim of the study was to evaluate the results of the developed method for bone grafting, a modified two-stage split technique for controlled ridge augmentation in horizontally atrophic posterior mandible, using radiological analysis data.Materials and Methods.The study group included 18 patients with horizontally atrophic posterior mandible. According to cone beam computed tomography, 39 jaw segments were assessed before plastic surgery and after applying the two-stage split-crest technique for controlled ridge augmentation. The alveolar ridge width was estimated in the area of its top and at a distance of 1, 3, 5 mm from it using the vector of future implant position and taking into account the angle of inclination of the atrophic region of the mandible.Results.When analyzing edentulous areas in the posterior mandible before treatment, there was rather a large angle of lingual inclination of the alveolar ridge. After 6 months, the average increase in bone tissue width in the region of the alveolar ridge top was 82%, it was 50.6% at a height of 1 mm from the top of the crest, 58.8% at 3 mm height, 46.7% at 5 mm (p≤0.05). Certain patterns of bone tissue growth were revealed depending on the structure of the reconstructed area. The most significant results were obtained in the molar segments of the mandible.Conclusion.The developed modified two-stage split technique for alveolar ridge augmentation allows achieving the required volume of bone tissue in the posterior mandible for successful implant treatment.

Assessment of the efficacy of posterior extra-short implant support for an interforaminal implant-supported fixed full-arch mandibular prosthesis

Aim The purpose of the present study was to determine whether it is useful to support a fixed full-arch prosthesis supported by interforaminal implants, with extra-short implants (4 mm) in the posterior region in order to eliminate the cantilever extensions, in posterior atrophic mandible cases. Methods Six different models including three or four interforaminal implants with or without support of posterior extra-short implants were formed. Straumann tissue-level implants (4.1x12mm and 4.1x4mm) were modeled for this study. Spherical loadings from canine and molar regions were applied to evaluate tension, compression, and von Mises stresses by implementing finite element analysis. Results In most conditions, four interforaminal implant supports provide balanced stress distributions, on the other hand, only three interforaminal implants were found to be insufficient biomechanically. The support of interforaminal implants with extra-short implants in the posterior region did not show the expected contribution, especially against the forces in the canine region. Also, the placement of four posterior extra-short implants does not make significant difference compared to the placement of two extra-short implants. Conclusions Implant-supported fixed prosthetic rehabilitation with cantilever extension of an edentulous mandible supported by four implants in the interforaminal region reached the best biomechanical results of the present study.

Custom-made 3D printed subperiosteal titanium implants for the prosthetic restoration of the atrophic posterior mandible of elderly patients: a case series

PurposeTo present the application of custom-made 3D-printed subperiosteal implants for fixed prosthetic restoration of the atrophic posterior mandible of elderly patients.MethodsBetween January 2017 and June 2018, all partially edentulous patients aged over 65 years, with two or more missing teeth in the posterior atrophic mandible, and who did not want to undergo bone regenerative procedures, were included in this study. These patients were rehabilitated with custom-made subperiosteal implants, designed from cone beam computed tomography (CBCT) and fabricated in titanium by means of direct metal laser sintering (DMLS). The outcome measures were fit and stability of the implants at placement, duration of the intervention, implant survival, and early and late complications. All patients were followed for 1 year after surgery.ResultsTen patients (four males, six females; mean age 69.6, SD ± 2.8, median 69, 95% CI 67.9–71.6) were included in the study. The fit of the implants was satisfactory, with a mean rating of 7 out of 10 (SD ± 1.6, median 7, 95% CI 6–8). Only two implants had insufficient fit, because of the presence of scattering in the CBCT; however, they were adapted to the sites during the interventions. The mean duration of the intervention was 44.3 min (SD ± 19.4, median 37, 95% CI 32.3–56.3). At the one-year follow-up, no implants were lost (survival rate 100%). One implant presented immediate postoperative complications with pain, discomfort and swelling, and two patients experienced late complications, having their provisional restorations fractured during the temporisation phase. All these complications were minor in nature, but the final complication rate amounted to 30% (three of ten patients).ConclusionsAlthough this study has limits (small patient sample and short follow-up), DMLS has proven to be an effective method for fabricating accurate subperiosteal implants, with high survival rates. This may represent an alternative treatment procedure in elderly patients with a severely atrophic posterior mandible, since it allows avoidance of regenerative bone therapies. Further studies are needed to confirm these outcomes.