Implantology and the Severely Resorbed Edentulous Mandible

Are short implants (≤8.5 mm) reliable in the rehabilitation of completely edentulous patients: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Limited data are available regarding the reliability of short implants (≤8.5 mm) in patients with resorbed completely edentulous jaws.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the clinical outcomes of short implants (intervention) versus long implants (≥10 mm, comparison) in the rehabilitation of completely edentulous jaws.

MATERIAL AND METHODS

The PubMed, Embase, and Cochrane CENTRAL databases were searched for randomized controlled trials (RCTs) comparing short and long implants supporting fixed or removable prostheses in completely edentulous jaws. Outcome measures included implant survival, marginal bone loss (MBL), and biological and technical complications. The risks of bias within and across the studies were assessed, and meta-analyses, sensitivity analyses, and subgroup analyses by types of prostheses, jaw locations, and follow-up length were performed.

RESULTS

A total of 4 RCTs with 158 participants were included. No significant difference was found between short implants and long implants regarding implant survival (RR=1.01, 95% CI: 0.97 to 1.05, P=.710, I2=70%) or MBL (MD=-0.19 mm, 95% CI: -0.39 to 0.02, P=.070, I2=94%). In subgroup analyses, when supporting fixed prostheses, short implants showed significantly less MBL than long implants (P<.001). In the mandible, short implants showed higher implant survival (P=.008) and less MBL (P<.001). Participants receiving long implants combined with bone augmentation procedures reported more postsurgery pain.

CONCLUSIONS

For completely edentulous jaws, short implants provide a reliable treatment alternative, as survival and MBL were not different when compared with those of long implants. However, additional high-level evidence is still needed to determine the long-term clinical outcomes of short implants in completely edentulous jaws.

Evaluation of the Success of Autogenous Block Grafting in Atrophic Maxillary and Mandibular Ridges Prior to and After Implant Placement

BACKGROUND

Dental implantology's success relies on adequate bone volume and quality, necessitating bone augmentation for implant placement. Primary lateral bone augmentation, utilizing autogenous block grafts, addresses horizontal bone loss.

OBJECTIVE

This study aims to evaluate the efficacy of autogenous block grafting, specifically ramus and fibula blocks, in addressing severe atrophic ridges before and after implant placement.

METHODS

Twenty-one patients underwent block grafting, predominantly using the ramus technique (80/20 ratio). CBCT measurements assessed horizontal grafting outcomes. Implant success and bone volume changes were analyzed.

RESULTS

Post-grafting, bone width increased from 1.8-3.1 mm to 4.5-6 mm, exceeding critical thresholds. Implant success reached 95%, indicating the grafting techniques' effectiveness.

CONCLUSION

Autogenous block grafting, especially with ramus and fibula blocks, transforms severe atrophic ridges, enabling successful implant integration. Long-term follow-up is essential for a comprehensive evaluation.

CLINICAL RELEVANCE

This study provides crucial insights into autogenous block grafting's transformative impact on challenging cases, guiding future applications in reconstructive dentistry.

The Use of Zirconia for Implant-Supported Fixed Complete Dental Prostheses: A Narrative Review

The success of implant-supported fixed complete dental prostheses (ISFCDPs) depends on multiple factors: some are related to the fixtures, such as fixture material, surface characteristics, positioning, and type of connection to prosthetic components; others are related to the prostheses, such as design and materials used. Zirconia is a material widely used in fixed prosthodontics, whether on natural teeth or on implants, with excellent results over time. Regarding the use of zirconia for ISFCDPs, the 2018 ITI Consensus Report stated that "implant-supported monolithic zirconia prostheses may be a future option with more supporting evidence". Since CAD/CAM technology and zirconia are being continuously innovated to achieve better results and performances over time, a narrative review of the literature seems necessary to focus research efforts towards effective and durable solutions for implant-supported, full-arch rehabilitations. The objective of the present narrative review was to search the literature for studies regarding the clinical performance of zirconia-based ISFCDPs. According to the results of this review, the use of zirconia for ISFCDPs showed good clinical outcomes, with high survival rates ranging from 88% to 100% and prosthetic complications that were restorable by the clinicians in most cases.

Does the Length of Mini Dental Implants Affect Their Resistance to Failure by Overloading?

Objective: We aimed to evaluate the failure resistance of different lengths of mini dental implants from the same manufacturer, and to assess their failure following overloading. Materials and Methods: According to the ISO 14801, 15 mini dental implants 2.4 mm in diameter, with lengths of 8.5 mm, 10 mm, or 13 mm, were subjected to compression loading until failure using a universal testing machine. The mean load-to-failure values for each length of the mini dental implants were calculated and analysed using SPSS®, via one-way ANOVA (p < 0.05). Results: The mean load to failure for mini dental implants was 329 N (SD 6.23), 326 N (SD 5.95), and 325 N (SD 6.99) for the 13 mm, 10 mm, and 8.5 mm implants, respectively. A comparison of means showed no significant difference between the groups (p = 0.70). The tested mini dental implants exhibited bending failure modes below the first thread. Conclusion: Under high compressive loading testing, there was no effect of the length on the failure of the mini dental implants following overloading. Moreover, all tested mini dental implants with different lengths showed the same failure mode and distortion location.

One-year prospective study on single short (7-mm) implant overdentures in patients with severely resorbed mandibles

OBJECTIVE

This prospective study aimed to assess the effectiveness of using a single short implant to retain a single-implant mandibular overdenture (SIMO) in participants with severely atrophic edentulous mandibles.

MATERIAL AND METHODS

The study sample included 18 edentulous participants with severely resorbed mandibular ridges and limited bone height in the symphyseal region sufficient for the insertion of a 7.0-mm-height implant. First, patients received new conventional dentures or had their dentures relined, followed by the insertion of a 3.75 x 7 mm morse-taper implant, and the incorporation of a stud-type attachment and a nylon retentive insert after a 3-month healing period. Implant stability quotient (ISQ) was measured at baseline and after 3 and 12 months. Patient-reported outcomes (satisfaction with the dentures and oral health-related quality of life) were assessed before implant placement and at the 3-, 6-, and 12-month follow-ups. Clinical-radiographic outcomes and the incidence of prosthodontic events were assessed throughout the follow-up period.

RESULTS

The implant survival rate was 100%. ISQ increased from baseline (72.7 ± 6.6) to the 3-month (82.0 ± 3.3) and 1-year (85.4 ± 2.9) follow-ups (p < .001). After 1 year, satisfaction with the mandibular prosthesis increased significantly, and the overall OHIP-Edent score decreased by 79.2%. No effects were found for the maxillary denture (p = .420). Due to dissatisfaction with treatment, two participants (11.1%) required additional implants after the 1-year follow-up and were considered as prosthodontic failures.

CONCLUSION

Single-implant mandibular overdenture retained by a short implant showed favorable outcomes after 1 year. Further studies with larger samples and longer follow-up periods are needed to confirm the findings of this single-group prospective study. The present study was registered at the Brazilian Clinical Trials Registry (REBEC), identifier RBR-7p2xmg. The trial registry occurred during the study execution, and its final approval was delayed because of several formatting adequacies required by the platform REBEC.

Regional differences in microarchitecture and mineralization of the atrophic edentulous mandible: A microcomputed tomography study

OBJECTIVE

The aim of the present study was to assess mineralization and trabecular microarchitecture in atrophic edentulous mandibles and to identify regional differences and relations with the extent of resorption.

METHODS

Cortical and trabecular bone volumes in anterior, premolar and molar regions of 10 edentulous cadaveric mandibles (5 males and 5 females; mean age ± SD: 85.4 ± 8.3 years) were assessed by microcomputed tomography. Mandibular height and Cawood & Howell classes were recorded. Concerning trabecular volumes, bone mineral density (BMD), bone volume fraction, trabecular tissue volume fraction, connectivity density, trabecular number, trabecular thickness, trabecular separation, degree of anisotropy, and structural model index were measured; concerning cortical volumes porosity, BMD and cortical thickness were measured.

RESULTS

In molar regions, the bone volume fraction and trabecular number were lower, whereas trabecular separation, degree of anisotropy and cortical BMD were higher compared to anterior regions. In premolar regions, mandibular height correlated negatively with trabecular number (Spearman's correlation r = 0.73, p = 0.017) and connectivity density (Spearman's correlation r = 0.82, p = 0.004), and correlated positively with trabecular separation (Spearman's correlation r = - 0.65, p = 0.04). Cortical BMD was higher at bucco-inferior cortex of molar and inferior border of premolar region and lower at anterior cranial buccal and lingual surface.

CONCLUSIONS

In the premolar region, increased resorption coincides with local impairment of trabecular bone quality. Cortical bone BMD is higher in areas with highest strains and lower in areas with most mandibular resorption. Trabecular bone volume and quality is superior in the anterior region of the edentulous mandible, which might explain improved primary stability of dental implants in this region.

Effect of mandibular residual ridge regularization on peri-implant wound healing when narrow diameter implants are used as overdenture retainers

STATEMENT OF PROBLEM

Alveolar ridge regularization involves the smoothing and minimal reduction of rough alveolar bone ridge to achieve adequate bone thickness around the implant. The effect of this procedure on peri-implant health is unclear.

PURPOSE

The purpose of this clinical study was to evaluate whether bone regularization affects the clinical and biological parameters of peri-implant health when narrow diameter implants are placed as mandibular implant overdenture retainers during initial healing and after occlusal loading.

MATERIAL AND METHODS

The need for mandibular ridge regularization in the anterior mandibular region was analyzed before the placement of 2 implants (2.9×10 mm, Facility; Neodent) in 21 participants provided with mandibular overdentures. Primary stability was measured by the insertion torque and implant stability quotient (ISQ). Clinical and biological evaluations measuring the plaque index, presence of calculus, probing depth, bleeding on probing index, gingival index, secondary stability (ISQ), and interleukine-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations in peri-implant crevicular fluid were measured during osseointegration on days 7, 15, 30, 60, and 90 and after loading on day 180 after implant placement. Multilevel mixed-effects linear regression analysis and the Kaplan-Meier test were used to analyze the data (α=.05).

RESULTS

The ISQ values showed significant differences on days 7 (P<.001) and 15 (P=.002) with higher values and on day 180 (P=.008) with a lower value compared with the baseline value in the ridge regularization group. Additionally, a significant decrease in probing depth was observed on days 60 (P=.008) and 180 (P=.027) compared with that on day 15 after implant placement. In the nonridge regularization group, significant decreases in probing depth were observed on days 30 and 180. Moreover, TNF-α levels in this group were significantly lower on days 30 (P=.001), 60, 90, and 180 (P<.001) when compared with the value on day 7 (P<.001). The ridge regularization group presented with significant differences in TNF-α and IL-1β levels on days 60 (P=.004) and 30 (P=.007), respectively, when compared with the values on day 7. The ISQ and probing depth in the ridge regularization group were associated with changes in TNF-α and IL-1β levels; furthermore, bone type, duration of edentulism, and mandibular bone atrophy were correlated with the clinical outcomes and TNF-α release. The implant survival rate was 67% in the nonridge regularization group and 100% in the ridge regularization group.

CONCLUSIONS

Mandibular ridge regularization appeared to be beneficial for peri-implant healing during the early stages and after 3 months of occlusal loading in patients with an atrophic ridge, prolonged time since edentulism, and poor bone quality.

Decision-Making in Implantology-A Cross-Sectional Vignette-Based Study to Determine Clinical Treatment Routines for the Edentulous Atrophic Mandible

This cross-sectional study aimed to investigate the influence of possible factors in the patient history on decision making in the therapy for a severely atrophied edentulous mandible. A vignette-based survey among 250 maxillofacial and oral surgeons was conducted. Determinants that could influence the therapy decision were patient age, smoking, fear of surgery, and radiotherapy in the head and neck area (the implant region is not in the direct radiation area). To achieve a suitable implant site, the options offered to the surgeons were bone split, bone block, augmentation with bone substitute material, and bone resection. There also was the option of rejecting any therapy. The response rate was 47%. Patient age, radiotherapy, and fear of surgery did not influence the approval of a therapy. Smoking was associated with a significantly lower endorsement of a treatment. Resection was preferred by a large majority to all other forms of therapy, regardless of the four determinants. Surgeons tend to refrain from bone block transplants in older patients. In summary, it can be said that, of the four determinants, only smoking influenced treatment refusal. Bone resection is the preferred therapy independent of all determinants.

Vestibuloplasty following denture hyperplasia resection with diode laser

Denture hyperplasia is a common clinical finding in patients wearing dentures. In this case report, a patient who was treated for denture hyperplasia presented with a post operative complication which led to inadequate vestibular depth. Inadequate vestibule is a common challenge dental surgeons encounter while considering fixed or removable prosthesis and implants. Objective is to achieve acceptable retention and aesthetics for the prosthesis by increasing the vestibular depth and also to manage the complication encountered during the resection procedure. Several techniques have been employed to increase the vestibular depth and the width of attached gingiva in the literature. In this case the denture hypereplasia was resected using diode laser which resulted in bone necrosis and opening of the wound post surgically. This was managed with curettage and PRF application. Following this the patient presented with inadequate vestibular depth. Vestibuloplasty was performed with Diode laser to deepen the vestibular depth and augment keratinized tissue to facilitate prosthetic rehabilitation. Three months following vestibuloplasy, patient presented with adequate vestibule. At six months follow up there was sufficient keratinized tissue to facilitate prosthetic rehabilitation. This case presents a unique way of managing a complication encountered after denture hyperplasia resection followed by vestibuloplasty with diode laser. The results obtained were clinically acceptable. PRF provides excellent results when used for the management of surgical complications like wound exposure. Laser technique is optimal for the treatment of soft tissue defects and is proven to be ideal for vestibuloplasty.

Calvarial graft resorption index in the reconstruction of the maxillary sinus in patients with atrophic maxillas: a prospective clinical study

The objective of this study was to assess the resorption index of particulate calvarial grafts in maxillary sinuses of patients undergoing total reconstruction of an atrophic maxilla with residual alveolar bone that was less than, or equal to, 3mm thick. Twenty-one maxillary sinus floor elevations were carried out using particulate calvarial grafts in 11 individuals with totally edentulous maxillas. All patients had computed tomography (CT) before (T0), and 48hours (T1) and six months after surgery (T2). For each CT scan, linear measurements were taken of sections of the anterior, medial, and posterior regions of the maxillary sinus. There was a significant increase in the height of the maxillary sinus floor when T0 was compared with T1 (p=0.001). There was a statistically significant reduction in all maxillary sinus measurements when T1 was compared with T2; the mean height reduction being 2.36mm (16.87%) in the anterior region, 3.53mm (22.47%) in the medial region, and 2.21mm (22.78%) in the posterior region (p=0.001). Mean resorption was 20.7%. Autogenous calvarial bone used alone is an option for graft material in pneumatised maxillary sinuses and in cases where there is limited alveolar bone.

Free fibula flap for reconstruction of the severely atrophic mandible: a retrospective study

The purpose of this retrospective study was to assess the feasibility of using a free fibula flap (FFF) for reconstruction of the alveolar region of the severely atrophic mandible, by determining bone stability after dental implant insertion and prosthetic rehabilitation in a series of eight female patients aged 36-65 years. Dental implant insertion was performed 3-4 months after reconstruction. Prosthetic loading was performed 3-4 months after implant insertion. The height of the reconstructed mandible after surgery was 21.20±1.87mm, with an increase of 8.80±1.71mm from the preoperative height. The height of the FFF immediately after reconstruction was 11.24±1.10mm; this showed a vertical loss of 0.99±0.52mm (8.79%) and maintenance of 91.21% of the initial height at a mean 14 months post-reconstruction. Applying the Wical and Swoope formula to estimate the original mandibular body height, it was found that the difference between this calculated height (21.17±3.76mm) and the reconstructed height (21.20±1.87mm) was only 0.03±3.17mm (0.14%). An overall insignificant decrease of 0.46±1.14 cm³ in FFF volume had occurred at 3-4 months after dental implant functional loading, while in two cases an increase in volume was found (1.22cm³ and 1.71cm³). The good and stable results obtained show that the FFF may be used to reconstruct the whole mandibular alveolar region, with the best possible outcomes.

Superioralization of the Inferior Alveolar Nerve and Roofing for Extreme Atrophic Posterior Mandibular Ridges with Dental Implants

Introduction:

Posterior mandibular ridges with extreme atrophy are usually combined with superficial location of the mental nerve and inferior alveolar nerves (IAN) and with a short residual mandibular ridge. As a result, dental implants cannot be placed in conjunction with IAN transposition alone. The aim of this paper is to introduce a new treatment approach to treat those patients.

Patients and Methods:

Eleven patients with 18 extreme atrophic posterior mandibular ridges characterized by superficial location of the IAN and short residual ridge had been treated during a 4-year period. The treatment approach included superior transposition of the IAN (IAN superioralization), 18 onlay bone block grafts harvested from the calvarial bone, implants placement through the block, and repositioning of the nerve under the onlay graft (IAN roofing). Patients were examined every 2–3 weeks; they received panoramic radiograph immediately after the surgery, at 4 months, at 6 months, and then once a year. Fixed prosthesis was performed after 4–5 months.

Results:

The donor sites of the bone blocks healed very well. The increase of bone height ranged between 4 and 6 mm at the recipient sites, and 63 long implants were placed (10–13 mm). All the patients were hospitalized 1–3 days. The healing process was uneventful, and the nerve recovery lasted a maximal period of 6 months. The implant success and survival rates were 100%. All patients received fixed prosthesis. The functional outcomes were satisfactory with marked improvement in the quality of life of the patients. The follow-up period was 12–58 months.

Conclusions:

Superioralization of the IAN and roofing is a fast and predictable option to treat extremely atrophic posterior mandibular ridges with fixed prosthesis supported by dental implants.

Remodeling of calvarial graft in increased atrophic maxillary thickness. A prospective clinical study

PURPOSE

This study evaluated the autogenous graft resorption rate in a calvarial block graft in the anterior region of an atrophic maxilla and compared it with the thickness of the remaining ridge.

MATERIALS AND METHODS

Twelve patients were included in the study. They were submitted to cranial calotte graft surgery, and there were 40 blocks in total. The thicknesses of the ridges in the crest, middle and apical regions of the blocks were evaluated by computed tomography scan at the times: preoperative (T0), 48 hours (T1) and 6 months (T2) after the reconstructions.

RESULTS

The resorption of the blocks from T1 to T2 was 13.4%. The greatest remodeling occurred in the alveolar bone crest (20.07%), followed by the middle portion (12.28%), and the apical region (9.5%), but the three regions did not significantly differ between times T1 and T2 (crest P = .07, middle P = .124, apical P = .131). Recipient site with the lowest thickness had the greatest resorption rates (up to 2 mm = 17.6%; from 2 to 4 mm = 17.52%) while than those with a thickness greater than 4 mm had a mean resorption of 8.81%.

CONCLUSIONS

The resorption of the grafts in this study was 13.4%. Higher resorption rates were observed in the alveolar crest areas, where the ridges were less thick.

[The use of autogenous free vascularized fibula transplant for the correction of severe mandibular atrophy]

The purpose of the study was to increase the effectiveness of surgical treatment and rehabilitation of patients with severe mandibular atrophy by means of autogenous free vascularized fibula transplant use with subsequent dental implants placement in the reconstructed mandible and implant-retained fixed dentures. In 2017 5 female patients underwent surgical treatment of severe mandibular atrophy with autogenous free vascularized fibula transplant in Maxillofacial Surgery department of CRID with additional nonvascularized iliac bone grafts and functional rehabilitation with implant-supported constructions in two of the cases. Due to its form, length and vascularization fibular bone represents a good plastic material for full length mandibular alveolar part reconstruction. The inclusion of the skin paddle in the autogenous free vascularized fibula transplant promotes secure primary closure of the surgical wound in the oral cavity. The use autogenous free vascularized fibula transplant in patients with severe mandibular atrophy with demands a thorough presurgical planning and intraoperative modeling.

Marginal bone loss 1 year after implantation: a systematic review for fixed and removable restorations

This systematic review analyses the difference of the mean marginal bone loss (MBL) 1 year after implantation depending on the fixation of the restoration. 889 publications on controlled clinical trials were identified, and based on inclusion and exclusion criteria, 22 studies were selected. Related to fixed restorations, the lowest MBL was 0.05±0.67 mm and the highest 1.37±0.5 mm. The MBL for removable restorations ranged from 0.13±0.35 mm to 1.03±0.65 mm. Three studies analyzed the MBL around implants of overdentures in the lower jaw. The estimate for this restoration type was 0.476 mm (95% CI: −0.305 to 1.258). 19 randomized controlled studies dealt with restorations which were fixed to the implants. The estimate for the mean MBL was 0.459 mm (95% CI: 0.325–0.593). There was a decrease in 1-year implant survival with an increase of 1 mm MBL (−0.083%; 95% CI: −0.179 to 0.0123; p=0.083) in fixed restorations. The difference in MBL between fixed and removable restorations was 0.363 mm (95% CI: −0.319 to 1.044; p=0.279). This systematic review indicates that implants with fixed and with removable restorations lead to comparable MBL.

Effects of interimplant distance and cyclic dislodgement on retention of LOCATOR and ball attachments: An in vitro study

STATEMENT OF PROBLEM

Evaluation of the long-term retentive behavior of overdenture attachments is necessary for successful treatment. Interimplant distance (IID) could affect the retention of these attachments.

PURPOSE

The purpose of this in vitro study was to assess the effects of IID and cyclic dislodgement on the retention of LOCATOR and ball attachments.

MATERIAL AND METHODS

Ball and LOCATOR attachments were connected to corresponding implant analogs. Metal housings were connected to each attachment. Thirty-six pairs of acrylic resin blocks were fabricated for 3 IIDs (19, 23, and 29 mm) and 2 attachments (n=6). Each pair consisted of 2 attachment assemblies parallel to each other with a specified IID. Overall, 1440 dislodgement cycles were applied by using a universal testing machine, and the maximum dislodging force was recorded after 0, 120, 360, 720, and 1440 cycles. Dislodging force data were analyzed by using repeated-measures 3-way analysis of variance, with the number of cycles as the within-subject factor for each specimen. Bonferroni-corrected Student t tests were used to resolve effects that were statistically significant. Moreover, dislodging force data were fit into an exponential decay model to determine the extent and rate of force decay for each attachment and IID studied.

RESULTS

The initial retention of LOCATOR attachments was significantly higher than that of ball attachments with IIDs of 23 and 29 mm, but no significant difference was noted with the 19-mm IID. After 1440 cycles, the retention was statistically similar with that of the 23-mm IID but was significantly higher for ball attachments with IIDs of 19 and 29 mm.

CONCLUSIONS

The IID is one of the factors that affect the retention of ball and LOCATOR attachments. The mean retention of both attachments was sufficient for all 3 IIDs at insertion and after 1440 cycles.

Bone surrogates provide authentic onlay graft fixation torques

Onlay graft bone augmentation is a standard practice to restore the loss of height of the alveolar ridge following loss of a tooth. Cranial grafts, lifted from the parietal bone, are sandwiched and used to bridge the bony defect in the jaw by means of small screws. During the elevation of the covering gum and subsequent screw placement, care has to be taken in order to preserve underlying nerves. Therefore, to avoid harm to the patient, a solid education of surgeons is essential, which requires training and experience. A simulator for cranial graft-lift training was already developed and shall be expanded to train the augmentation of the lifted implants. Therefore, in this study, synthetic bones for onlay block graft screw placement with realistic haptics for the screw application training were evaluated and compared with human specimens. Six different polyurethane based bone surrogate composites, enriched with varying amounts of calcium-based mineral fillers and blowing agents, were developed. The haptical properties of these synthetic bones were validated for screw placement and compared with human parietal bone specimens. For that, bones were pre-drilled, screws were automatically inserted using a customized testbench and the slope of the screw-insertion torques were analyzed. The slope of the screw insertion torques of the human reference bones was 56.5 ± 14.0 * 10^-3 Nm/deg, Surrogates with lower amounts of mineral fillers and blowing agents showed lower torques than the human bone. Synthetic bones, validated for drilling, milling and sawing in an earlier study, also achieved significantly lower torques, which were only the half of the human parietal bones. Two intermediate stages of the aforementioned material compositions, consisting of 75% mineral filler with 0.75% blowing agent and 100% mineral filler with 1.00% blowing agent revealed results comparable with human bone (57.4 ± 10.2 *10^-3 Nm/deg, p = 0.893 and 54.9 ± 11.1 *10^-3 Nm/deg, p = 0.795, respectively). In conclusion, our findings suggest that, two newly developed polyurethane-based materials mimicking the haptical properties of an onlay bone graft screw fixation, have been identified. Thus, these surrogates are capable of mimicking real bone tissue in our simulator for the education of novice surgeons.

All-On-Four Protocol With Immediate Load on Short Implants in an Atrophic Mandible: A Case Report with a 4-Year Follow-Up

Purpose:

Edentulism has been demonstrated to have negative social and psychological effects on individuals that include adverse impacts on facial and oral esthetics, masticatory function and speech abilities, that when combined, are translated into significant reductions in patients’ quality of lives. It is well-known that immediate placement of implants is a challenging surgical procedure that requires proper treatment planning and surgical techniques. Therefore, the present study describes a 4-year follow-up case report where short implants were placed in an atrophic mandibule and were loaded with the utilization of an all-on-four prosthetic protocol.

Case report:

A 54 year-old woman dissatisfied with her oral and facial esthetics, masticatory function and speech ability came to the implantology clinic of the Positivo University seeking for oral rehabilitation treatment. After detailed physical and clinical examination, a Computer Tomography scan (CT-scan) was performed to determine the patient’s bone ridge density, dimensions and eligibility for the placement of dental implants. The CT-scan results have indicated the presence of an extremely atrophic mandibular bone ridge. The CT-scan was also used as an aid during the final restoration treatment planning in terms of vertical dimension of occlusion, masticatory function, and stabilization of the lower denture. An all-on-four protocol supported by short implants was then treatment-planned to reduce time, costs and morbidity, and also to achieve superior immediate esthetic results and masticatory function. To reconstruct the patient’s atrophic edentulous mandibule, 4 short implants, including 2 distally tilted, were placed with a final torque of 45 Ncm.

Results:

Following the development and implementation of a complex treatment plan, the patient displayed stable soft and hard tissues at 4-year postoperative follow-up assessment, demonstrating the effectiveness of the all-on-four technique supported by short implants.

Conclusion:

Within the limits of this study, the present case report demonstrated that the all-on-four prosthetic protocol with immediate loading on short implant was effective in an atrophic mandible over a 4-year follow-up.

Resorption of the mandibular residual ridge: A micro-CT and histomorphometrical analysis

OBJECTIVES

The aim of this study was to investigate whether the extent of mandibular resorption and gender is related to the bone turnover and microarchitecture of the edentulous mandible.

PARTICIPANTS AND METHODS

A mandibular bone sample was obtained at canine position from 36 edentulous participants (50% women; mean age: 65 years) during dental implant surgery. All female participants were postmenopausal. Mandibular height, duration of edentulous state and resorption pattern (Cawood classification) were recorded. Microcomputed tomography was used to determine bone mineral density, bone volume fraction, trabecular connectivity density, trabecular number, trabecular thickness and trabecular separation. Histomorphometric analysis was used to assess bone turnover: osteoid area and surface were measured as a parameter for bone formation and osteoclast numbers were determined as a parameter for bone resorption. Correlations between micro-CT, histomorphometrical parameters and clinical data were analysed with correlation coefficients and parametric and non-parametric tests.

RESULTS

Lower mandibular height was strongly associated with higher bone mineral density in trabecular bone. Women showed higher osteoclast numbers in trabecular bone than men. In trabecular bone of women, bone volume was significantly related to osteoclast numbers, osteoid surface and osteoid area.

CONCLUSIONS

The higher trabecular bone mineral density found in the edentulous mandible could either indicate a restructuring process of the resorbed mandible or suggests that the inferior region of the mandible is more highly mineralised. In women, higher bone turnover is associated with lower bone volume, suggesting an effect of postmenopausal oestrogen deficiency on bone turnover in the edentulous mandible.

Application of interconnected porous hydroxyapatite ceramic block for onlay block bone grafting in implant treatment: A case report

Autogenous block bone grafting as treatment for alveolar ridge atrophy has various disadvantages, including a limited availability of sufficiently sized and shaped grafts, donor site morbidity and resorption of the grafted bone. As a result, interconnected porous hydroxyapatite ceramic (IP-CHA) materials with high porosity have been developed and used successfully in orthopedic cases. To the best of the author's knowledge, this is the first report of clinical application of an IP-CHA block for onlay grafting for implant treatment in a patient with horizontal alveolar atrophy. The present study performed onlay block grafting using an IP-CHA block to restore bone volume for implant placement in the alveolar ridge area without collecting autogenous bone. Dental X-ray findings revealed that the border of the IP-CHA block became increasingly vague over the 3-year period, whereas CT scanning revealed that the gap between the block and bone had a smooth transition, indicating that IP-CHA improved the process of integration with host bone. In follow-up examinations over a period of 5 years, the implants and superstructures had no problems. An IP-CHA block may be useful as a substitute for onlay block bone grafting in implant treatment.

Rehabilitation of the atrophic mandible with short implants in different positions: A finite elements study

OBJECTIVE

The aim of this study was to analyze whether the use of inclined short implants without lower transcortical involvement (test model - SI), thus preserving the mandibular lower cortical bone, could optimize stress distribution.

MATERIALS AND METHODS

Six identical atrophic mandible models were created featuring 8mm of height at the symphysis. Two study factors were evaluated: implant length and angulation. Implant length was represented either by short implants (7mm) with preservation of the mandibular lower cortical bone or standard implants (9mm) with a bicortical approach and 3 possible implant positioning configurations: 4 distally-inclined implants at 45° (experimental model), all-on-four, 4 vertical implants. All tridimensional (3D) models were analyzed using the Finite Element Method (FEM) and the Ansys Workbench software.

RESULTS

The maximum stress on the bone at the cervical region of the implants in the experimental model was 132MPa and transcortical involvement with implant inclination yielded higher values (171MPa). Regarding von Mises stress on the retaining screw of the prosthesis, 61MPa was recorded for the experimental model while upright implants had the highest values (223MPa). At the acrylic base, 4MPa was recorded for the experimental model whereas models with upright implants showed the highest stress values (11MPa).

CONCLUSION

Rehabilitation of severely resorbed mandibles with 4 short implants placed distally at 45°, without lower transcortical involvement, were biomechanically more favorable, generating lower stress peaks, than the models with short implants on an all-on-four, or on an upright configuration, with or without lower transcortical involvement.

Effect of Interimplant Distance and Cyclic Loading on the Retention of Overdenture Attachments

AIM

The purpose of this in vitro study was to investigate the effect of interimplant distance and cyclic loading on the retention of two locator attachment systems.

MATERIALS AND METHODS

A total of 72 acrylic resin blocks were fabricated and divided into six groups of six pairs each. Locators of DIO and 3i implant systems were positioned on analogs in three different interimplant distances (19, 23, and 29 mm). The blocks were attached to a universal testing machine, and 1,440 dislodging cycles by the force of 136 N were applied. After 0, 120, 360, 720, and 1,440 cycles, the retention was recorded. Three-way analysis of variance (ANOVA) was used to test for differences in retention between the various combinations of the locator, interimplant distance, and cyclic loadings.

RESULTS

Interimplant distance was significantly associated with retention, independent of the locator system used, and dislodge-ment force cycles. Mean retention was significantly higher under the 3i system relative to the DIO system (p < 0.0001). This association varied with both interimplant distance (p > 0.0001) and dislodgement force (p < 0.0001) as well as across the various combinations of distance and cycle (p < 0.0001).

CONCLUSION

Interimplant distances could affect the initial retention of locator attachments. There was little difference in retention between distances of 23 and 29 mm across all cycles when both locator systems were combined. Distance of 23 mm was associated with superior retention in the DIO system. With regard to the speed of retention decrease, the 23 mm distance was associated with better performance.

CLINICAL SIGNIFICANCE

Interimplant distance could play a significant role in overdenture retention with locator attachments.

Dental implant treatment for renal failure patients on dialysis: a clinical guideline

Chronic kidney disease (CKD) is a worldwide public health problem that is growing in prevalence and is associated with severe complications. During the progression of the disease, a majority of CKD patients suffer oral complications. Dental implants are currently the most reliable and successful treatment for missing teeth. However, due to complications of CKD such as infections, bone lesions, bleeding risks, and altered drug metabolism, dental implant treatment for renal failure patients on dialysis is more challenging. In this review, we have summarized the characteristics of CKD and previous publications regarding dental treatments for renal failure patients. In addition, we discuss our recent research results and clinical experience in order to provide dental implant practitioners with a clinical guideline for dental implant treatment for renal failure patients undergoing hemodialysis.

Short implants to support mandibular complete dentures - photoelastic analysis

This study evaluated the stress behavior around short implants in edentulous atrophic mandibles. Six groups included implants with two diameters regular and wide (4 and 5 mm) and three lengths (5, 7 and 9 mm) as follows: Ci9 (9 x 4 mm), Ci7 (7 x 4 mm), Ci5 (5 x 4 mm), Wi9 (9 x 5 mm), Wi7 (7 x 5 mm) and Wi5 (5 x 5 mm). These groups were compared to the control group CG (11 x 4 mm). The analysis was performed with the photoelastic method (n = 6). Each model comprised 4 implants with the same length and diameter connected by a chromium-cobalt bar that simulates a fixed denture. A 0.15 kg force was applied at the end of the cantilever (15 mm), and the maximum shear stress was recorded around the distal and subsequent implants. The stress values were determined, and the quantitative data (Fringes®) were submitted to statistical analysis with one-way ANOVA and the Dunnett test (p < 0.05). It was observed that the reduction in implant length increased stress values with a significant difference (p < 0.05) between CG Ci7 and Ci5, while the increase in implant diameter reduced the stress values without any differences found between short and long implants. Implants with 5 and 7 mm with regular diameter increased stress levels while short implants with larger diameters experienced similar stress to that of longer implants.

Dental implant treatment in a young woman after marginal mandibulectomy for treatment of mandibular gingival carcinoma: a case report

Dental implants play an important role in postoperative rehabilitation after surgical treatment of oral cancer through the provision of prosthetic tooth replacement. Two major implant prosthesis designs are available: fixed implant-supported prostheses and implant-supported overdentures. We herein report a case of a 16-year-old female patient who underwent alveolar ridge resection for treatment of mandibular gingival carcinoma. Following surgery, oral rehabilitation was attempted using an implant-supported overdenture on a gold bar retainer splinting four implants. However, the patient was not satisfied with this prosthesis because of mucosal pain and discomfort, and she gradually ceased its use. Consequently, contact with the opposing teeth caused wear of the prosthetic screws. We elected to replace the implant-supported overdenture with an implant-fixed prosthesis approximately 16 years after insertion of the overdenture to prevent further wear of the prosthetic screws. The patient was highly satisfied with the improved stability of the implant-fixed prosthesis. This case report indicates that the clinician must occasionally re-evaluate and sometimes alter the direction of treatment, even after definitive therapy has been completed.

Controlling Bone Graft Substitute Microstructure to Improve Bone Augmentation

Vertical bone augmentation procedures are frequently carried out to allow successful placement of dental implants in otherwise atrophic ridges and represent one of the most common bone grafting procedures currently performed. Onlay autografting is one of the most prevalent and predictable techniques to achieve this; however, there are several well documented complications and drawbacks associated with it and synthetic alternatives are being sought. Monetite is a bioresorbable dicalcium phosphate with osteoconductive and osteoinductive potential that has been previously investigated for onlay bone grafting and it is routinely made by autoclaving brushite to simultaneously sterilize and phase convert. In this study, monetite disc-shaped grafts are produced by both wet and dry heating methods which alter their physical properties such as porosity, surface area, and mechanical strength. Histological observations after 12 weeks of onlay grafting on rabbit calvaria reveal higher bone volume (38%) in autoclaved monetite grafts in comparison with the dry heated monetite grafts (26%). The vertical bone height gained is similar for both the types of monetite grafts (up to 3.2 mm). However, it is observed that the augmented bone height is greater in the lateral than the medial areas of both types of monetite grafts. It is also noted that the higher porosity of autoclaved monetite grafts increases the bioresorbability, whereas the dry heated monetite grafts having lower porosity but higher surface area resorb to a significantly lesser extent. This study provides information regarding two types of monetite onlay grafts prepared with different physical properties that can be further investigated for clinical vertical bone augmentation applications.

Systematic Review and Meta-Analysis on Incidence of Altered Sensation of Mandibular Implant Surgery

Altered sensation (including paresthesia, dysesthesia and hypoesthesia) after mandibular implant surgery may indicate transient or permanent injury of the inferior alveolar nerve and the mental branch, and considerably lower patients’ satisfaction about the therapy. Previous studies have shown a great degree of variability on the incidence of altered sensation. We here reported the incidence of altered sensation after mandibular implant surgery based on a meta-analysis of 26 articles published between 1990.1.1 and 2016.1.1. Study quality and risk of bias was assessed and the studies with a lower score were excluded in the meta-analysis. Data synthesis was performed using the logistic-normal random-effect model. The meta-analyses revealed that the short-term (10 days after implant placement) and long-term (1 year after implant placement) incidence was 13% (95% CI, 6%-25%) and 3% (95% CI, 1%-7%), respectively. (2) For the patients who initially reported altered sensation, 80% (95% CI, 52%-94%) of them would return to normal sensation within 6 months after surgery, and 91% (95% CI, 78%-96%) of them would return to normal sensation one year after surgery. We concluded that dentist-patient communication about the risk of altered sensation is critical to treatment planning, since the short-term incidence of altered sensation is substantial (13%). When a patient reports altered sensation, regular assessment for 6 months would help tracing the changes of symptoms. In terms of long-term follow-up (1 year after surgery), the incidence is much lower (3%) and most patients (91%) would return to normal sensation.

A 15-Year Comparative Prospective Study of Surgical and Prosthetic Care and Aftercare of Overdenture Treatment in the Atrophied Mandible: Augmentation Versus Nonaugmentation

BACKGROUND

Different treatment strategies for the atrophied mandible are described in literature. The need for long term care and aftercare for these strategies is sparsely described, however.

PURPOSE

To prospectively assess the need for prosthetic and surgical care and aftercare of two implant treatment strategies for the atrophied mandible.

MATERIALS AND METHODS

Forty edentulous elderly patients were randomly assigned according to a balanced allocation method to a treatment strategy: dental implants in combination with an augmentation procedure versus a nonaugmentation procedure. All surgical and prosthetic care and aftercare were scored from the first visit until 15 years after implant placement.

RESULTS

Twenty elderly patients completed the 15-year follow-up. As expected, the augmentation group needed significantly more surgical time than the nonaugmentation group (338 vs 145 minutes), but the need for prosthetic care and surgical/prosthetic aftercare was comparable. Implant survival was lower in augmented mandibles (88.7% vs 98.7%, p < .05). Aftercare mainly consisted of routine inspections; the need for prosthetic adjustments was minor. Surgical aftercare was hardly needed.

CONCLUSION

The only difference in the need for surgical and prosthetic (after) care was the extra time needed for performing augmentation surgery and the higher risk on implant loss in augmented mandibles. Otherwise, the need for care and aftercare was of the same magnitude. Thus, when applicable, nonaugmentation surgery is preferred as no general anesthesia is needed and the morbidity is low.

Implant-supported rehabilitation after treatment of atrophic mandibular fractures: report of two cases

OBJECTIVE

The objective of this article is to present options of rehabilitation with dental implants in two cases of severely atrophic mandibles (<10 mm) after rigid internal fixation of fractures.

PATIENTS AND METHOD

Two patients who sustained fractures in severely atrophic mandibles with less than 10 mm of bone height were treated by open reduction and internal fixation through a transcervical access. Internal fixation was obtained with 2.4-mm locking reconstruction plates. The first patient presented satisfactory bone height at the area between the mental foramens and after 2 years, received flapless guided implants in the anterior mandible and an immediate protocol prosthesis. The second patient received a tent pole iliac crest autogenous graft after 2 years of fracture treatment and immediate implants. After 5 months, a protocol prosthesis was installed in the second patient.

RESULTS

In both cases, the internal fixation followed AO principles for load-bearing osteosynthesis. Both prosthetic devices were Branemark protocol prosthesis. The mandibular reconstruction plates were not removed. Both patients are rehabilitated without complications and satisfied with esthetic and functional results.

CONCLUSION

With the current techniques of internal fixation, grafting, and guided implants, the treatment of atrophic mandible fractures can achieve very good results, which were previously not possible.

Stability of edentulous, atrophic mandibles after insertion of different dental implants. A biomechanical study

OBJECTIVES

Fractures of the atrophic edentulous mandible are a rare complication that can become severe after the insertion of dental implants. This in vitro study investigated the effects of different implant settings varying in number, diameter, and length. and the influence of a fixed bar.

MATERIALS AND METHODS

In biomechanical experiments on artificial mandibles, an unmodified reference group, four implant settings with two different implants, and the effect of adding a fixed bar to these settings were tested. All specimens were loaded with incisal biting forces until failure due to fracture.

RESULTS

Implants weakened all specimens significantly compared with those in the reference group. Without a fixed bar, four short and thick implants showed the best results, with high significance. With a fixed bar, four long and thin implants withstood the highest loads. The addition of fixed bars reduced the differences between the implant settings. Fixed bars did not show increased stability for all groups; however, these groups showed a higher mean strength.

CONCLUSIONS

Four implants with a short and thick design should be the first choice when implants are placed without a fixed bar in an atrophic mandible. With a fixed bar, four long and thin implants should be used.

Immediate loading short implants inserted on low bone quantity for the rehabilitation of the edentulous maxilla using an All-on-4 design

More studies evaluating the outcome of short-length dental implants in immediate loading are needed. To evaluate the use of short-length tapered implants in immediate loading for complete edentulous maxillae rehabilitations using an All-on-4 design. This retrospective clinical study included a cohort of 43 patients with 172 implants (74 short-length implants) inserted in low bone quantity. The patients were followed between 4 months and 6 years (average = 3 years). Outcome measures were implant survival, marginal bone remodelling, biological and mechanical complications. Two patients with four short-length implants were lost to follow-up during the first year. Three short and three long implants failed in four patients, rendering an overall cumulative survival rate implant and patient level, respectively, of 95.7% and 95.1% for short implants, 100% for regular implants and 96.6% and 95.2% for long implants. The average marginal bone remodelling at 1 and 3 years was 0.97 and 1.25 mm for the short implants, 0.82 and 0.87 mm for regular implants and 0.87 and 0.98 mm for long implants. Three patients presented 4 short-length implants with peri-implant pockets (3 implants in 2 patients were pseudo-pockets). Mechanical complications were registered in 13 patients (7 provisional prostheses fractures and 6 abutment screw loosening). All complications were treated successfully. Within the limitations of this clinical study, the short-term outcome of fixed prosthetic complete edentulous maxillae rehabilitations supported by short-length implants inserted in low bone quantity areas is viable. Long-term clinical studies are necessary for evaluating the outcome of these implants.

Retrospective assessment of survival rate for short endosseous dental implants

PURPOSE

The aim of this study was to determine the survival rate of short implants that were placed in a residency program. In addition, the potential influence of diabetes, smoking, sinus grafting, guided bone regeneration, and implant type on survival was analyzed.

METHODS

Through a retrospective chart review, patient information and parameters for short implants being equal or less than 10 mm and regular implants being more than 10 mm were collected. The cumulative survival rate and implant and patient information from 213 consecutively placed implants from May 2002 through October 2011 were analyzed.

RESULTS

The average survival time for short implants was 47.3 months, with a range of 6 to 141 months. The implant survival rate was 95.77% for short implants, which was not statistically significant from the regular implants. Smoking had a statistically significant negative effect on the survival rate of short implants. No statistical differences were found with implant survival rates for other factors.

CONCLUSION

It can be concluded that short implants can be predictably placed in the mouth with a high survival rate and that smoking has a negative influence on the survival rate of the short implants.

Severe mandibular atrophy treated with a subperiosteal implant and simultaneous graft with rhBMP-2 and mineralized allograft: a case report

A 71-year-old patient was successfully rehabilitated by means of a 3D model-derived, hydroxyapatite-coated titanium subperiosteal mandibular implant. The implant was specifically designed to allow bone augmentation. The deficient bone was simultaneously grafted with mineralized bone allograft and recombinant bone morphogenetic protein -2 (rhBMP-2). The 32-month postoperative cone beam computerized tomography follow-up showed vertical bone augmentation beneath the implant frame.

Surgical complications after implant placement

Placement of dental implants in the maxillofacial region is routine and considered safe. However, as with any surgical procedure, complications occur. Many issues that arise at surgery can be traced to the preoperative evaluation of the patient and assessment of the underlying anatomy. In this article, the authors review some common and uncommon complications that can occur during and shortly after implant placement. The emphasis of each section is on the management and prevention of complications that may occur during implant placement.

Evolving surgical prosthetic rehabilitation protocol for success of dental implant placed in distracted alveolar ridge

BACKGROUND

Remodelling of bone in the form of resorption generally follows the extraction of a tooth. During all stages of atrophy of the alveolar ridge, characteristic shapes result from the resorptive process, as influenced by anatomic alterations in the alveolar bone. Various ridge augmentation procedures have been documented as predictable means of establishing new vital bone for implant placement, out of which distraction osteogenesis is one such modality. Hence the following study has been conducted to evolve a surgico- prosthetic rehabilitation protocol in grossly atrophic alveolar ridge by distraction osteogenesis and subsequent implant placement and to provide an effective alternative to lost dental tissue to serving soldiers, their families and ex-servicemen of the Indian Army in a cost effective manner.

METHODS

A total of 30 patients with ridge defects in age group between 18 to 70 years were selected for the study. The net success rate of distraction procedure was 93.33% (100% in maxilla and 80% in mandible) with 2 cases deemed as failures out of a total of 30 cases. The average amount of defect compensated was 76.1% (85.1% and 59.5% in maxilla and mandible respectively).

RESULTS

For the implant surgical procedure the success rate was 100% and subsequently prosthetic rehabilitation on implants was proved to be successful.

CONCLUSION

Distraction ostoeogenesis of an atrophied ridge for further implant placement certainly proves to be successful procedure by this study. Further studies in the same procedure using a larger sample size will definitely be more beneficial.

Survival rate of osseointegrated implants in atrophic maxillae grafted with calvarial bone: a retrospective study

The aim of this study was to evaluate the clinical survival rate of osseointegrated implants placed in the atrophic maxilla that has been reconstructed by means of autogenous bone grafts harvested from a cranial calvarial site. Further, we sought to analyse the level of peri-implant bone after prosthetic rehabilitation and to determine subjective patient satisfaction with the treatment performed. This study conformed to the STROBE guidelines regarding retrospective studies. Twenty-five patients who had received osseointegrated implants with late loading in the reconstructed atrophic maxilla were included in the study. The survival rate and level of peri-implant bone loss were evaluated. A questionnaire related to the surgical and prosthetic procedures was completed. The observed implant survival rate was 92.35%. The mean bone loss recorded was 1.76mm in the maxilla and 1.54mm in the mandible. The results of the questionnaire indicated a high level of patient satisfaction, little surgical discomfort, and that the patients would recommend the procedure and would undergo the treatment again. From the results obtained, it is concluded that the cranial calvarial site is an excellent donor area; calvarial grafts provided stability and maintenance of bone volume over the course of up to 11 years.

Piezosurgery applied to implant dentistry: clinical and biological aspects

Piezosurgery is a new and modern technique of bone surgery in implantology. Selective cutting is possible for different ultrasonic frequencies acting only in hard tissues (mineralized), saving vital anatomical structures. With the piezoelectric osteotomy technique, receptor site preparation for implants, autogenous bone graft acquistition (particles and blocks), osteotomy for alveolar bone crest expansion, maxillary sinus lifting, and dental implant removal can be performed accurately and safely, providing excellent clinical and biological results, especially for osteocyte viability. The aim of this review was, through literature review, to present clinical applications of piezosurgery in implant dentistry and outline their advantages and disadvantages over conventional surgical systems. Moreover, this study addressed the biological aspects related to piezosurgery that differentiate it from those of bone tissue approaches. Overall, piezosurgery enables critical operations in simple and fully executable procedures; and effectively, areas that are difficult to access have less risk of soft tissue and neurovascular tissue damage via piezosurgery.

Repair of a fractured implant overdenture gold bar: A clinical and laboratory technique report

This clinical report explains a convenient, efficient, yet effective alternative for management of fractured substructure cast bars for implant-retained overdentures. The technique allows the fracture to be repaired at low cost and short time without remaking the substructure and the denture and further allowing the patient to keep their denture. The report sketches the clinical and laboratory procedures involved in the repair.

Vitamin D supplementation enhances the fixation of titanium implants in chronic kidney disease mice

Vitamin D (Vit D) deficiency is a common condition in chronic kidney disease (CKD) patients that negatively affects bone regeneration and fracture healing. Previous study has shown that timely healing of titanium implants is impaired in CKD. This study aimed to investigate the effect of Vit D supplementation on implant osseointegration in CKD mice. Uremia was induced by 5/6 nephrectomy in C57BL mice. Eight weeks after the second renal surgery, animals were given 1,25(OH)2D3 three times a week intraperitoneally for four weeks. Experimental titanium implants were inserted into the distal end of femurs two weeks later. Serum measurements confirmed decreased 1,25(OH)2D levels in CKD mice, which could be successfully corrected by Vit D injections. Moreover, the hyperparathyroidism observed in CKD mice was also corrected. X-ray examination and histological sections showed successful osseointegration in these mice. Histomorphometrical analysis revealed that the bone-implant contact (BIC) ratio and bone volume (BV/TV) around the implant were significantly increased in the Vit D-supplementation group. In addition, resistance of the implant, as measured by a push-in method, was significantly improved compared to that in the vehicle group. These results demonstrate that Vit D supplementation is an effective approach to improve the fixation of titanium implants in CKD.

Clinical study on survival rate of short implants placed in the posterior mandibular region: resonance frequency analysis

OBJECTIVE

Short implants are increasingly used, but there is doubt about their performance being similar to that of regular implants. The aim of this study was to compare the mechanical stability of short implants vs. regular implants placed in the edentulous posterior mandible.

MATERIAL AND METHODS

Twenty-three patients received a total of 48 short implants (5 × 5.5 mm and 5 × 7 mm) and 42 regular implants (4 × 10 mm and 4 × 11.5 mm) in the posterior mandible. Patients who received short implants had <10 mm of bone height measured from the bone crest to the outer wall of the mandibular canal. Resonance frequency analysis (RFA) was performed at time intervals T0 (immediately after implant placement), T1 (after 15 days), T2 (after 30 days), T3 (after 60 days), and T4 (after 90 days).

RESULTS

The survival rate after 90 days was 87.5% for the short implants and 100% for regular implants (P < 0.05). There was no significant difference between the implants in time intervals T1, T2, T3, and T4. In T0, the RFA values of 5 × 5.5 implants were higher than values of 5 × 7 and 4 × 11.5 implants (P < 0.05). A total of six short implants that were placed in four patients were lost (three of 5 × 5.5 mm and three of 5 × 7 mm). Three lost implants started with high ISQ values, which progressively decreased. The other three lost implants started with a slightly lower ISQ value, which rose and then began to fall.

CONCLUSIONS

Survival rate of short implants after 90 days was lower than that of regular implants. However, short implants may be considered a reasonable alternative for rehabilitation of severely resorbed mandibles with reduced height, to avoid performing bone reconstruction before implant placement. Patients need to be aware of the reduced survival rate compared with regular implants before implant placement to avoid disappointments.

Osseointegration of short titan implants: A pilot study in pigs

Reduced vertical bone level in the implantation area is often considered one of the limiting factors before implant insertion. Inserting implants of reduced length might be useful in order to avoid vertical bone augmentation prior to implantation. To the present day, no official guidelines exist as to the optimal length for these implants. It is nevertheless well known that the stability of an implant depends primarily on its osseointegration, which could otherwise be influenced by modifying implant surface texture. The aim of our study was to evaluate osseointegration in correlation with implant length and surface texture. Three different variations of titan implants (n=5) were compared: two types, each with an acid-etched and ceramic blasted surface, were inserted in the upper jaw of adult female minipigs at different lengths (tioLogic ST Shorty, 5mm length; tioLogic ST, 9mm length) and were compared to a control group (tioLogic ST, 9mm length, ceramic blasted surface). Eight weeks after unloaded healing, bone tissue specimens containing the implants were processed, stained with Masson-Goldner-trichrome and analyzed histologically. Regardless of implant length and surface texture, new bone formation with no signs of inflammation could be detected in the area of the threads. Implants with a modified surface showed no statistically significant difference in bone-implant-contact (BIC) (tioLogic ST Shorty, 56.5%; tioLogic(©)ST; 77.2%), but a statistically significant difference could be found, when the 9mm implants were compared to the control group (BIC 48.9%). Surface modification could positively influence osseointegration as well as contribute to overcoming the adverse effects of length reduction.