Histologic Evaluation of Sinus Grafting Materials After Peri-implantitis-Induced Failure: A Case Series

PURPOSE

This human case series presents the clinical and histologic results of five cases of peri-implantitis with subsequent sinus graft infections. Complications may follow maxillary sinus augmentation procedures. It is possible to have an inflammatory reaction, movement of the implant inside the sinus, formation of an insufficient quantity of osseous tissue, and the production of an oroantral fistula. Complications following maxillary subantral augmentation procedures are relatively rare; however, the risks and benefits of any surgery must be carefully evaluated at the onset.

MATERIALS AND METHODS

In this case series, bacterial proliferation from infected implants into the grafted biomaterial in sinus cavities was examined. In five cases, removal of infected implants from augmented sinuses did not result in resolution of the infection, but rather in persistence of the infection in the area of the sinus augmentation procedure. Intraoral examination revealed edema/redness in two cases and edema and sinus tract formation in another case. In all cases, surgical curettage of the affected maxillary sinuses was performed. The inserted biomaterials and the accompanying inflammatory tissue infiltrate were totally removed with curettes. The sample was sent for a histopathologic examination. The maxillary sinuses were filled with an autologous platelet gel.

RESULTS

Necrotic bone was found lining the different biomaterial grafts. Macrophages were observed around the grafted particles. No blood vessels were observed.

CONCLUSION

This case series is the first to document the spread of infection from an implant surface to the entirety of the graft in the maxillary antrum. Complete removal of all infected bone graft material is the treatment of choice in such cases.

Animal models for peri-implant mucositis and peri-implantitis

The treatment of infectious diseases affecting osseointegrated implants in function has become a demanding issue in implant dentistry. Since the early 1990s, preclinical data from animal studies have provided important insights into the etiology, pathogenesis and therapy of peri-implant diseases. Established lesions in animals have shown many features in common with those found in human biopsy material. The current review focuses on animal studies, employing different models to induce peri-implant mucositis and peri-implantitis.

Stress and Inflammation as a Detrimental Combination for Peri-implant Bone Loss

The causes of peri-implant bone loss continue to be controversial. To determine the impact of biomechanical stress and inflammation, we investigated a total of 80 interforaminal implants in situ for more than 10 years. Two stress groups, with 14 patients each, were established: a low-stress situation with single-standing implants, and an increased-stress situation with splinted implants. To categorize inflammation, we introduced a Composite Inflammation Score using 4 inflammatory parameters. Peri-implant bone loss was calculated from digital panoramic radiographs. To differentiate between the effects of stress and inflammation, we compared bone loss in both stress groups at equivalent levels of inflammation. With greater Composite Inflammation Score values, a clear discrepancy between single-standing and splinted implants was evident (p = 0.117/0.000, regression analysis; p = 0.135/0.000, analysis of variance; p = 0.002, t tests). While stress and inflammation alone may not necessarily be detrimental factors, the presence of stress heightens peri-implant bone loss significantly as inflammation increases.

Peri-implant Inflammation Defined by the Implant-Abutment Interface

An implant-abutment interface at the alveolar bone crest is associated with sustained peri-implant inflammation; however, whether magnitude of inflammation is proportionally dependent upon interface position remains unknown. This study compared the distribution and density of inflammatory cells surrounding implants with a supracrestal, crestal, or subcrestal implant-abutment interface. All implants developed a similar pattern of peri-implant inflammation: neutrophilic polymorphonuclear leukocytes (neutrophils) maximally accumulated at or immediately coronal to the interface. However, peri-implant neutrophil accrual increased progressively as the implant-abutment interface depth increased, i.e., subcrestal interfaces promoted a significantly greater maximum density of neutrophils than did supracrestal interfaces (10,512 ± 691 vs. 2398 ± 1077 neutrophils/mm2). Moreover, inflammatory cell accumulation below the original bone crest was significantly correlated with bone loss. Thus, the implant-abutment interface dictates the intensity and location of peri-implant inflammatory cell accumulation, a potential contributing component in the extent of implant-associated alveolar bone loss.

Survival of Brånemark System Mk III implants and analysis of risk factors associated with implant failure

The purpose of this study was to retrospectively investigate the outcomes of Brånemark System Mk III TiUnite/Groovy implants placed in patients at Kobe University Hospital. Various risk factors for implant failure, including mechanical coupling, were investigated by univariate and multivariate analysis. The predictive variables investigated included age, sex, smoking habit, general health, history of radiation therapy, application of a dentomaxillary prosthesis, type of prosthesis, use of alveolar bone augmentation, site of implant insertion, mechanical coupling between implants, and the length and diameter of the implants. Of the 907 implants investigated, only 23 were unsuccessful; the overall survival rate was 96.7%. Increased age, radiation therapy, application of a removable prosthesis or dentomaxillary prosthesis, lack of mechanical coupling between implants, and shorter implants (≤8.5mm) were significant risk factors for implant failure according to univariate analysis (P<0.05). Multivariate analysis identified a significant association (P<0.05) between dental implant failure and a lack of mechanical coupling between implants (odds ratio 6.88) and shorter implants (≤8.5mm) (odds ratio 3.43). The findings of this study demonstrated multivariate relationships between various risk factors and dental implant failure.

Into the Paradigm of Local Factors as Contributors for Peri-implant Disease: Short Communication

Although some systemic conditions have been associated with peri-implant disease, local contributing factors largely remain to be determined. This study aimed at evaluating, based on clinical photographs obtained from peri-implantitis treatment publications, the possible local contributing factors involved in its development based upon a survey obtained from three experienced clinicians (> 20 years of expertise). Cohen's kappa index was used to test the interexaminer reliability. "Too-buccal implant position" was the only parameter to reach almost perfect interexaminer agreement (κ = 0.81). "Thin-tissue biotype" and "minimal presence of keratinized mucosa" demonstrated moderate agreement (κ = 0.43 and κ = 0.58, respectively). The rest of the parameters studied based on clinical photographs were fair or poor. Therefore, based on this clinicians' survey, implants too buccally placed, minimal or a lack of keratinized mucosa, and thin-tissue biotype might contribute to a higher susceptibility of developing peri-implantitis. These factors must be the focus of attention in future cross-sectional studies on the incidence of peri-implant diseases.

Surgical Management of Implant-Associated Gingival Fenestrations

Soft tissue fenestrations are extremely rare in the natural dentition and have only recently been reported on dental implants. Although the pathogenesis of their formation is not completely understood, several predisposing risk factors have been identified, some of which may affect dental implants as well. This article presents a thorough review of the literature pertaining to gingival fenestration. It also describes the surgical management of lesions developed approximately six years following osseointegration of two dental implants.

Saving an Integrating Implant Involved with Endodontic Implant Pathology Using Surgical Treatment

Endodontic implant pathology (EIP) refers to cases in which endodontic infections cause infections in adjacent implants, and vice versa. This case report demonstrates the successful resolution of two types of EIPs, implant endodontitis and endodontic implantitis, by endodontic intervention with surgical treatment. In case 1, the patient complained of tooth discomfort after implant placement in the adjacent tooth. The tooth was sensitive to percussion and showed slight mobility with a negative reaction to an electric pulp test. The symptoms persisted despite conventional root canal treatment, and surgical treatment of the symptomatic tooth and implant lesion was performed. In case 2, the patient suffered from repeated infection around a newly installed implant. The adjacent devitalized tooth exhibited a periapical lesion that was contiguous with the implant. Conventional root canal treatment and retreatment did not successfully resolve the symptoms. Surgical root canal therapy was then performed with regenerative biomaterials as needed. Neither case showed radiographic or clinical evidence of failure after 4 and 5 years of follow-up, respectively, after the surgery and the adjacent implants were successfully osseointegrated. Endodontic intervention combined with surgical treatment resolved both types of EIPs and led to tooth preservation and successful osseointegration of adjacent implants.

Implants in free fibula flap supporting dental rehabilitation - Implant and peri-implant related outcomes of a randomized clinical trial

OBJECTIVES

The objective of this study was to assess the difference in success rates of implants when using two or four implant-supported-overdentures following segmental mandibular reconstruction with fibula free flap.

METHODS AND DESIGNS

This prospective, parallel designed, randomized clinical study was conducted with 1:1 ratio. At baseline, all participants already had segmental reconstruction of mandible with free fibula flap. The participants were randomized into two groups: Group-I received implant-supported-overdentures on two tissue-level implants and Group-II received implant-supported-overdentures on four tissue-level implants. Success rates of the implants were evaluated at 3 months, 6 months and 12 months following implant loading using marginal bone level changes as well as peri-implant indices (Buser et al., 1990).

RESULTS

52 patients were randomized into two treatment groups (26 each), out of which 18 patients (36 implants) of Group-I and 17 patients (68 implants) of Group-II were evaluated. One implant in Group-I was lost due to infective complications and one patient in the same group had superior barrel necrosis. There was a statistically significant increase at both time points (p = 0.03, p = 0.04 at 6 months, 12 months) in the amount of marginal bone loss in Group-I (0.4 mm, 0.5 mm at 6 months, 12 months) as compared to Group-II (0.1 mm, 0.2 mm at 6 months, 12 months). There were no clinically significant changes peri-implant parameters between both groups. Peri-implant soft tissue hyperplasia was seen in both groups, 32% of implants at 3-months, 26% at 6-months and 3% at 12-months follow-up.

CONCLUSION

The results of this study show that patients with 2-implant-supported-overdentures had higher marginal bone loss as compared to patients with 4-implant-supported-overdentures. There were no clinically significant differences in peri-implant soft tissue factors in patients with 2- or 4-implant-supported-overdentures. Hyperplastic peri-implant tissues are common in the early implant-loading phase and tend to decrease over time under appropriate management.

Association between tumor necrosis factor-alpha G-308A polymorphism and dental peri-implant disease risk: A meta-analysis

BACKGROUND

Tumor necrosis factor-alpha (TNF-α) is a potent immune-inflammatory mediator involved in the regulation of bone resorption. The single nucleotide polymorphism G-308A in the TNF-α gene increases the level of this cytokine. This phenomenon is also related to several diseases. Although the association between TNF-α (G-308A) polymorphism and dental peri-implant disease has been investigated, results have remained controversial. Hence, we performed this meta-analysis to provide a comprehensive and systematic conclusion on this topic.

METHODS

We performed a systematic literature search in PubMed, Embase, ISI Web of Science, Cochrane Library, and Chinese National Knowledge Infrastructure until July 2015. A fixed-effect model was established to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). The calculated values were then used to assess the strength of the association between the TNF-α (G-308A) polymorphism and the dental peri-implant disease risk. The heterogeneity between included studies was evaluated with Cochran Q and I statistics. Interstudy publication bias was investigated with a funnel plot.

RESULTS

Six eligible studies were included in this meta-analysis. The pooled ORs did not reveal a significant relationship between the TNF-α (G-308A) polymorphism and the disease susceptibility. Subgroup analyses in terms of ethnicity and disease type yielded similar results.

CONCLUSION

Our meta-analysis revealed that TNF-α (G-308A) polymorphism was not significantly associated with the risk of dental peri-implant disease. However, further studies with large sample sizes should be performed to verify these results.

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.

Biomechanical evaluation of oversized drilling on implant stability - an experimental study in sheep

OBJECTIVE

To evaluate the effect of oversized drilling on implant success and secondary stability.

METHODS

The experimental study was conducted in Turkey from January to July 2013, after approval by the ethics committee of the University of Ankara, and comprised 2 female sheep. Alumina blasted implants 4mm in diameter and 10mm in length were employed; 16 implant sites were prepared on the proximal tibias of the 2 sheep. In the right tibia, a standard preparation with 3.5mm diameter was performed in the control group, while in the left tibia, an over-preparation with 4.2mm diameter was performed at the experimental group. The implants of the control group were non-mobile, while the experimental group had rotational and vertical movements. The initial implant stability was measured using the resonance frequence analysis. Animals were sacrificed after 12 weeks, and resonance frequence analysis and reverse torque values were measured.

RESULTS

In the experimental group, the mean resonance frequence analysis value was 60.25±7.46 (range: 49-74) at the end of the 12-week healing period. There was no statistically significant difference between the two groups (p=0.926). In the removing stage, the mean reverse torque values was 97.75±22.23N/cm (range: 68.63-138.83) for control group and 96.25±21.93N/cm (range: 63.34-126.9) for the experimental group (p=0.84).

CONCLUSIONS

Osseointegration can be achieved in the absence of primer stability in the 12-week period of healing time even for alumina-blasted implants.

Histomorphometric Analysis of Contaminated Autogenous Tooth Graft Materials After Various Sterilization

PURPOSE

The purpose of this study was to evaluate histomorphometrically contaminated autogenous tooth graft materials, which were resterilized.

MATERIALS AND METHODS

The intentional defects (diameter: 8 mm, depth: 4 mm) were formed around implant fixture on the iliac crest of 6 mongrel dogs. Autogenous tooth graft materials were made by extracted premolars. After the contamination of the tooth materials, graft procedure was performed; no contaminated group (control group), contaminated groups (nonsterilization group [group 1], ethylene oxide [EO] gas group [group 2], and autoclave group [group 3]). The bone-to-implant contact (BIC) and the new bone formation rate (NBFR) were evaluated after sacrifice.

RESULTS

The BIC and NBFR of groups 1 and 3 were significantly lower than the control group after 4 weeks. The BIC and NBRF of group 3 were significantly lower than the control group after 8 weeks. However, the BIC and NBRF of group 2 was not significantly different comparing with the control group after 4 and 8 weeks.

CONCLUSION

Sterilization using EO gas may be more favorable than high-pressure sterilization in cases the reuse of contaminated autogenous tooth graft materials.

[Stress final element analysis at the abatement-implant-bone interface]

According to a research

AIM

we carried out the comparative final element analysis of stress in implant construction and the bone surrounding it. The best result showed implants with platform switching and cone interface between implant and abatement. Such combination of elements allows maintaining implant construction stability and decrease the load on cortical bone.

Peri-Implant Disease--A Significant Complication of Dental Implant Supported Restorative Treatment

Over past several decades, oral rehabilitation of fully or partially edentulous patients with dental implants has become a routine procedure in daily practice. Dental implant supported and retained prosthesis can provide a wide variety of treatment options to patients due to their high predictability and survival rate. While many patients treated with dental implants have had high long term success, they are not completely free of complications. Proper patient selection, treatment planning, surgical and prosthodontic procedures, material selection and routine maintenance around the peri-implant tissues are keys to this long term success rate.

Interaction of titanium, zirconia and lithium disilicate with peri-implant soft tissue: study protocol for a randomized controlled trial

BACKGROUND

Against the background of increasing use of dental implants, and thus an increasing prevalence of implant-associated complications, a deeper understanding of the biomolecular mechanisms in the peri-implant tissue is needed. Peri-implant soft tissue is in direct contact with transmucosal dental implant abutments. The aim of this trial is to distinguish the biomolecular and histological interactions of various dental abutment materials with peri-implant soft tissue.

METHODS/DESIGN

The study is designed as a prospective, randomized, investigator-initiated clinical pilot trial with blinded assessment. We will ultimately include 24 eligible patients who opt for implant treatment to replace a single missing posterior tooth. Three months after implantation (submerged procedure), the study begins with the second-stage surgery. Each of the 24 patients will be given three different transmucosal abutments (zirconia, lithium disilicate, titanium) consecutively. The sequence in which the three materials are used is randomized. Peri-implant crevicular fluid is sampled weekly around the respective abutment for biomolecular analyses. After one month of wearing time, the stamping press from the second-stage surgery is used to gain a narrow gingival ring biopsy around the abutment for immunohistochemical analyses. The next abutment is then inserted. The same procedure is used for all three abutments. After sampling is completed, the patients will receive a definitive crown. The primary outcome measure of the trial is biomolecular detection of specific markers in the peri-implant crevicular fluid: matrix metalloproteinase 8, interleukin- 1β, polymorphonuclear elastase, and myeloid-related protein MRP8/14 (calprotectin). Secondary outcome measures include immunohistochemical analyses and clinical parameters.

DISCUSSION

The study design will allow us to perform correlation analyses between the clinical indices with biomarkers' expression in the interface of the transmucosal abutments and the peri-implant soft tissue. A deeper understanding of the three abutment materials' interactions with peri-implant soft tissue will help us understand the formation mechanisms of implant-associated complications and then develop prevention strategies.

TRIAL REGISTRATION

The trial is registered at the German Clinical Trial Register and the International Clinical Trials Registry Platform by the WHO under DRKS00006555 (Registered on 27 October 2014).

Review of unusual intraoperative and postoperative complications associated with endosseous implant placement

OBJECTIVES

Common complications associated with dental implant surgery are well recognized and are usually explained to patients during the process of informed consent. For the general dental practitioner, the periodontist, and the oral and maxillofacial surgeon, it is relevant to also be familiar with less frequent complications. This review gathers unusual complications of this surgical procedure and presents unique complications from single case reports.

METHOD AND MATERIALS

Studies were located using systematic searches in Medline and the Cochrane Library electronic databases. Key words included the terms "implant", "dental", "oral", "complication", "unusual", and "rare". References from the relevant articles were also double-checked. The review was limited to English and German language articles, published within the last 15 years.

RESULTS

17 different unusual complications were identified. The majority of studies report five different complications: permanent nerve injury, damage to teeth adjacent to the implant, excessive bleeding resulting in hematoma of the floor of the mouth, mandibular fracture, and displacement of implants into the maxillary sinus. Benign paroxysmal positional vertigo and a plunging ranula were reported sporadically. Another 10 complications were only described once in our literature search.

CONCLUSION

Unusual complications are challenging. It is important for the dental practitioner to be aware of all the possible complications and to recognize them early so that adequate therapy can immediately be ensured.

Peri-implant mucosal recession: Clinical significance and therapeutic opportunities

Peri-implant mucosal recessions can be a major esthetic problem in the anterior zone, whereas in the functional zone the coverage of exposed implants is not of primary significance, as methods to clean these structures are more important. In these situations free gingival grafts are often used to deepen the vestibule and increase the amount of attached keratinized mucosa. Complete coverage of mucosal recessions around dental implants is still a challenging procedure, but it seems that recessions up to 2 mm can be successfully grafted with subepithelial connective tissue grafts.

Implant-related nerve injuries

Injuries to branches of the trigeminal nerves are a known complication during dental implant placement. These injuries tend to be more severe than those experienced during other dentoalveolar procedures. This article reviews the types of nerve injuries and areas and situations of which clinicians should be cognizant when placing dental implants. Strategies to avoid injuries, and a management algorithm for suspected nerve injuries, are also discussed.

Key local and surgical factors related to implant failure

The concept of osseointegration has revolutionized the treatment options for the replacement of missing teeth in both partially and completely edentulous patients. Dental implants are widely used because clinical practice and studies have documented its successful outcomes. However, implants can occasionally fail, and such failures can be classified as early or late. Measures that can aid in the early recognition of failing osseointegrated implants are needed, as are measures that can facilitate appropriate treatment methods aimed at saving failing implants by determining the probable etiologic factors. This article summarizes our current understanding of the local factors that can be linked to implant failure.

Persistent pain and neurosensory disturbance after dental implant surgery: prevention and treatment

Nerve trauma caused by dental implant placement is associated with altered sensation and chronic pain. Complete or partial loss of sensation is often reported by patients who have experienced nerve trauma during implant surgery. Some patients report persistent pain and neurosurgery disturbance long after the normal healing time has passed. In addition, neuropathic pain is reported after implant surgery. Practitioners who place dental implants must be familiar with the differential diagnosis, prevention, and management of neuropathic pain. This article provides insights into the prevention and management of neurosensory deficits and chronic persistent neuropathic pain and considerations for patient referral.