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

Influence of repeated implant-abutment manipulation on the prevalence of peri-implant diseases in complete arch restorations. A retrospective analysis

PURPOSE

To evaluate the effects of repeated abutment manipulation on the prevalence of peri-implant diseases.

MATERIALS AND METHODS

A total of 27 edentulous patients (n = 108 implants) immediately restored with double-crown retained implant-supported prostheses were identified for this retrospective study. The test included the one-abutment, one-time care concept (n = 18 patients, n = 72 implants, OAOT) and the control abutment replacement (n = 9 patients, n = 36 implants, AR). A mixed effects model regression was conducted for the variable diagnosis (healthy, peri-implant mucositis, and peri-implantitis) with predictors abutment replacement (presence/absence), number of abutment replacement, category of keratinized mucosa (KM) (2 < KM ≥2 mm), and radiographic bone loss (BL).

RESULTS

After 3-15 years (mean 10.2 ± 2.8 years), the prevalence of peri-implant mucositis and peri-implantitis in patients in the AR group was 11.1% and 88.9%, corresponding to 22.2% and 55.6% at the implant level, respectively. In OAOT group, none of the implants showed peri-implant mucositis, whereas the prevalence for peri-implantitis at patient and implant level amounted to 5.6% and 5.6%, respectively. The increased number of abutment replacements was significantly associated with the increased probability to diagnose peri-implant mucositis and peri-implantitis (OR: 6.13; 95% CI [2.61, 14.39]) (p < 0.001), whereas the presence of keratinized mucosa was not founded as a significant cofounder. The estimated mean BL in AR group was 1.38 mm larger than in OAOT group (p = 0.0190).

CONCLUSIONS

The OAOT concept was associated with a lower prevalence of peri-implant diseases.

Does an untreated peri-implant dehiscence defect affect the progression of peri-implantitis?: A preclinical in vivo experimental study

OBJECTIVE

To investigate the early impact of plaque accumulation in a buccal dehiscence defect on peri-implant marginal bone resorption.

MATERIALS AND METHODS

In six male Mongrel dogs, four dental implants were placed in the posterior maxilla on both sides (two implants per side). Based on the group allocation, each implant was randomly assigned to one of the following four groups to decide whether buccal dehiscence defect was prepared and whether silk ligation was applied at 8 weeks post-implant placement for peri-implantitis induction: UC (no defect without ligation); UD (defect without ligation); LC (no defect with ligation); and LD (defect with ligation) groups. Eight weeks after disease induction, the outcomes from radiographic and histologic analyses were statistically analyzed (p < .05).

RESULTS

Based on radiographs, the exposed area of implant threads was smallest in group UC (p < .0083). Based on histology, both the distances from the implant platform to the first bone-to-implant contact point and to the bone crest were significantly longer in the LD group (p < .0083). In the UD group, some spontaneous bone fill occurred from the base of the defect at 8 weeks after implant placement. The apical extension of inflammatory cell infiltrate was significantly more prominent in the LD and LC groups compared to the UC group (p < .0083).

CONCLUSION

Plaque accumulated on the exposed implant surface had a negative impact on maintaining the peri-implant marginal bone level, especially when there was a dehiscence defect around the implant.

The distally anchored connective tissue graft platform for papilla enhancement: A case report

BACKGROUND

As the need for using dental implants to replace single missing teeth grows, so does the demand for greater esthetic results. However, achieving complete interproximal papillae fill in single-tooth implant restorations remains a challenge. The distally anchored connective tissue platform is a novel soft tissue augmentation technique that consists of harvesting an autogenous connective tissue graft from the palate, folding it, and positioning it at the level of the distal occlusal and buccal surfaces with the help of a distal sling suture to the adjacent distal tooth.

METHODS

This case report describes how a maxillary central incisor with compromised hard and soft tissues were replaced using a comprehensive treatment plan.

RESULTS

The clinical outcomes showed stable mucosal margin levels and complete papillae fill. The patient expressed satisfaction with the achieved results.

CONCLUSIONS

The distally anchored connective tissue graft platform performed at the time of implant placement emerges as a viable and effective soft tissue augmentation technique that yields highly esthetic results.

KEY POINTS

Why is this case new information? To the best of our knowledge, this is the first case report in the literature using the distally anchored connective tissue platform. What are the keys to successful management of this case? Adequate diagnosis and decision-making, resulting in a treatment plan focused on reconstructing both soft and hard tissues in a single-tooth implant within the esthetic area, yield favorable clinical, radiological, and patient-reported outcomes. What are the primary limitations to success in this case? The primary limitation of this study is its reliance on a single case report.

Tooth- and implant-related prognostic factors in treatment planning

Following a comprehensive patient examination, including the assessment of periodontal and peri-implant diseases as well as considering the patient's needs, a pretherapeutic prognosis for each tooth and implant is given. Teeth and implants with a secure pretherapeutic prognosis require simple procedures and may be regarded as secure abutments for function and with a doubtful pretherapeutic prognosis usually need a comprehensive therapy. Such teeth and implants must be brought into the category with a secure prognosis by means of additional therapy such as endodontic, restorative, and surgical procedures. Teeth and implants with a hopeless pretherapeutic prognosis should be extracted/explanted during the initial phase of cause-related therapy (i.e., infection control). For example, teeth with vertical root fracture or unrestorable caries and implants with mobility or unrestorable malposition fall into the category of hopeless units. The primary goal of periodontal and peri-implant therapy should be to arrest disease progression. The latest consensus statement highlights that periodontitis can be successfully controlled and treated teeth can be retained for life. Nevertheless, for patients with uncontrolled contributing factors, the endpoints might not always be achievable, and low disease activity may be an acceptable therapeutic goal. Similarly, the management of peri-implantitis frequently requires surgical intervention following nonsurgical therapy due to incomplete treatment outcomes. Different surgical modalities can be effective and lead to significant improvement; however, achieving complete resolution of peri-implantitis is challenging, not always predictable, and can depend on multiple baseline factors. Therefore, this review aims at summarising available evidence on the rationale for incorporating systemic, lifestyle-related, clinical, and radiographic prognostic factors into treatment planning of patients diagnosed with periodontal and peri-implant diseases.

Risk indicators associated with peri-implant diseases: a retrospective cross-sectional study of Colombian patients with 1 to 18 years of follow-up

PURPOSE

Peri-implant mucositis (PIM) and peri-implantitis (PI) are multicausal conditions with several risk factors contributing to their pathogenesis. In this study, we retrospectively investigated risk variables potentially associated with these peri-implant diseases (PIDs) over a follow-up period of 1 to 18 years.

METHODS

The study sample consisted of 379 implants placed in 155 patients. Single-visit clinical and radiographic evaluations were employed to determine the presence or absence of PIDs. Parameters related to the patient, site, surgery, implant, and prosthetic restoration were documented. The relationships between risk variables and the occurrence of PIDs were individually examined and adjusted for confounders using multivariate binary logistic regression models.

RESULTS

The prevalence rates of PIM and PI were 28.4% and 36.8% at the patient level and 33.5% and 24.5% at the implant level, respectively. Poor oral hygiene, active gingivitis/periodontitis, preoperative alveolar ridge deficiency, early or delayed implant placement, implant length of 11.0 mm or less, and poor restoration quality were strong and independent risk indicators for both PIDs. Furthermore, a follow-up period of more than 5 years and a loading time of more than 4 years were important indicators for PI. Simultaneously, age and smoking status acted as modifiers of the effect of mesiodistal (MD) and buccolingual (BL) widths of restoration on PI.

CONCLUSIONS

In this study population, oral hygiene, periodontal status, preoperative alveolar ridge status, implant placement protocol, implant length, and the quality of coronal restoration appear to be robust risk indicators for both PIM and PI. Additionally, the length of follow-up and functional loading time are robust indicators of PI. Furthermore, the potential modifying relationships of age and smoking status with the MD and BL widths of restoration may be crucial for the development of PI.

The Role of Radiographic Imaging in the Diagnosis and Management of Periodontal and Peri-Implant Diseases

This article highlights the role of dental imaging techniques, including periapical, bitewing, panoramic, and cone-beam computed tomography images, in the diagnostic and therapeutic decision-making process for patients with periodontal and peri-implant disease. A brief overview of common radiographic findings of periodontal disease, including periodontitis, and peri-implantitis is also provided.

A retrospective study of dynamic navigation system-assisted implant placement

BACKGROUND

To evaluate the accuracy of implant placement assisted by a dynamic navigation system, as well as its influencing factors and learning curve.

METHODS

At Macao We Care Dental Center, 55 cases of implant placement using dynamic navigation were retrospectively evaluated. To evaluate their accuracy, the apex, tip, and angle deviations of preoperatively planned and postoperatively placed implants were measured. The effects of the upper and lower jaws, different sites or lateral locations of dental implants, and the length and diameter of the implants on accuracy were analyzed, as well as the variation in accuracy with the increase in the number of surgical procedures performed by dentists.

RESULTS

The implant had an apex deviation of 1.60 ± 0.94 mm, a tip deviation of 1.83 ± 1.03 mm, and an angle deviation of 3.80 ± 2.09 mm. Statistical differences were observed in the tip deviation of implants at different positions based on three factors: jaw position, lateral location, and tooth position (P < 0.05). The tip deviation of the anterior teeth area was significantly greater than those of the premolar and molar areas. There were no statistically significant differences in apex deviation, tip deviation, or angle deviation between the implants of different diameters and lengths (P > 0.05). There were significant differences in the angle deviation between the final 27 implants and the first 28 implants. Learning curve analysis revealed that angle deviation was negatively correlated with the number of surgical procedures, whereas the regression of apex deviation and tip deviation did not differ statistically.

CONCLUSIONS

The accuracy of dynamic navigation-assisted dental implants meets the clinical needs and is higher than that of traditional implants. Different jaw positions, lateral locations, and implant diameters and lengths had no effect on the accuracy of the dental implants guided by the dynamic navigation system. The anterior teeth area had a larger tip deviation than the posterior teeth area did. As the number of dynamic implantation procedures performed by the same implant doctor increased, the angle deviation gradually decreased.

Influence of buccal bone wall thickness on the peri-implant hard and soft tissue dimensional changes: A systematic review

BACKGROUND

The significance on the association between the peri-implant bucco-lingual dimension (BLD) at the stage of implant placement and the occurrence of biological and esthetic complications is yet unknown.

MATERIAL AND METHODS

Systematic screening of electronic sources was carried out to identify clinical and preclinical studies reporting on the baseline BLD and/or buccal bone thickness (BBT) values. A secondary objective was to assess the effect of simultaneous grafting at sites with deficient or no buccal bone wall (BBW) at baseline. The primary outcome variables were BBT, BLD, and buccal vertical bone loss (VBL) at re-evaluation. Moreover, radiographic, clinical, and patient-reported outcome measures (PROMs) were evaluated.

RESULTS

Overall, 12 clinical and four preclinical studies met the inclusion criteria. Inconsistencies were found in defining the critical BBT across the clinical and preclinical data evaluated. The clinical evidence demonstrated that during healing, dimensional changes occur in the alveolar bone and in the BBW that may compromise the integrity of the peri-implant bone, leading to VBL and mucosal recession (MR), particularly in scenarios exhibiting a thin BBW. The preclinical evidence validated the fact that implants placed in the presence of a thin BBW, are more prone to exhibit major dimensional changes and VBL. Moreover, the clinical data supported that, in scenarios where dehiscence-type defects occur and are left for spontaneous healing, greater VBL and MR together with the occurrence of biologic complications are expected. Furthermore, the augmentation of dehiscence-type defects is associated with hard and soft tissue stability. PROMs were not reported.

CONCLUSIONS

Dimensional changes occur as result of implant placement in healed ridges that may lead to instability of the peri-implant hard and soft tissues. Sites presenting a thin BBW are more prone to exhibit major changes that may compromise the integrity of the buccal bone and may lead to biologic and esthetic complications.

Significance of buccal bone wall thickness on the fate of peri-implant hard and soft tissues: A systematic review

BACKGROUND

The significance of the association between the peri-implant buccolingual dimension (BLD) at the stage of implant placement and the occurrence of biological and esthetic complications is yet unknown.

MATERIAL AND METHODS

Systematic screening of electronic sources was carried out to identify clinical and preclinical studies reporting on the baseline BLD and/or buccal bone thickness (BBT) values. A secondary objective was to assess the effect of simultaneous grafting at sites with deficient or no buccal bone wall (BBW) at baseline. The primary outcome variables were BBT, BLD, and vertical bone loss (VBL) at re-evaluation. Moreover, radiographic, clinical- and patient-reported outcome measures (PROMs) were evaluated.

RESULTS

Overall, 12 clinical and four preclinical studies met the inclusion criteria. The clinical evidence demonstrated that during healing, dimensional changes occur in the alveolar bone and in the BBW that may compromise the integrity of bone around a dental implant. The preclinical evidence validated the fact that implants placed in the presence of thin BBW are more prone to exhibit major dimensional changes. Moreover, the clinical and preclinical data supported that in scenarios where dehiscence-type defects are left for spontaneous healing, greater VBL and mucosal recession (MR) together with the occurrence of biologic complications are expected. Furthermore, the augmentation of dehiscence-type defects is associated with hard and soft tissue stability.

CONCLUSIONS

Dimensional changes occur as a result of implant placement in healed ridges that may lead to VBL and MR. Thin BBW (≲2 mm) are prone to exhibit major postchanges that may compromise the integrity of the buccal bone, biologic and esthetic complications.

Implant prosthodontic design as a predisposing or precipitating factor for peri-implant disease: A review

Over the past decade, emerging evidence indicates a strong relationship between prosthetic design and peri-implant tissue health. The objective of this narrative review was to evaluate the evidence for the corresponding implant prosthodontic design factors on the risk to peri-implant tissue health. One of the most important factors to achieve an acceptable implant restorative design is the ideal implant position. Malpositioned implants often result in a restorative emergence profile at the implant-abutment junction that can restrict the access for patients to perform adequate oral hygiene. Inadequate cleansability and poor oral hygiene has been reported as a precipitating factors to induce the peri-implant mucositis and peri-implantitis and are influenced by restorative contours. The implant-abutment connection, restorative material selection and restoration design are also reported in the literature as having the potential to influence peri-implant sort tissue health.

Impact of local predisposing/precipitating factors and systemic drivers on peri‐implant diseases

BACKGROUND

Strong evidence suggests the infectious nature of peri-implant diseases occurring in susceptible hosts. Epidemiological reports, though, indicate that peri-implantitis is a site-specific entity. Hence, the significance of local factors that may predispose/precipitate plaque accumulation and the impact of systemic drivers that alter the immune response are relevant in the prevention and management of peri-implant disorders.

PURPOSE

The purpose of the present review is to shed light on the significance of local and systemic factors on peri-implant diseases, making special emphasis on the associations with peri-implantitis.

METHODS

The biologic plausibility and supporting evidence aiming at providing a concluding remark were explored in the recent scientific literature for local predisposing/precipitating factors and systemic drivers related to peri-implant diseases.

RESULTS

Local predisposing factors such as soft tissue characteristics, implant position and prosthetic design proved being strongly associated with the occurrence of peri-implant diseases. Hard tissue characteristics, however, failed to demonstrate having a direct association with peri-implant diseases. Robust data points toward the strong link between residual sub-mucosal cement and peri-implant diseases, while limited data suggests the impact of residual sub-mucosal floss and peri-implantitis. Systemic drivers/habits such as hyperglycemia and smoking showed a strong negative impact on peri-implantitis. However, there is insufficient evidence to claim for any link between metabolic syndrome, atherosclerotic cardiovascular disease, and obesity and peri-implant diseases.

CONCLUSION

Local predisposing/precipitating factors and systemic drivers may increase the risk of peri-implant diseases. Therefore, comprehensive anamnesis of the patients, educational/motivational programs and exhaustive prosthetically-driven treatment planning must be fostered aiming at reducing the rate of biological complications in implant dentistry.

Bone construction surgery: A case report using recombinant human platelet-derived growth factor-BB

BACKGROUND

The position and condition of bone largely sets the stage for functional and esthetic implant success. In bone construction surgery, creating a sustainable functional matrix is complex, but necessary, to enable long-term mechanotransduction and maintenance of soft tissue support.

METHODS

A patient with a severe peri-implantitis ridge defect in the anterior maxilla underwent bone construction surgery simultaneous with implant removal using a composite bone graft (mineralized freeze dried bone allograft + xenograft) enhanced with recombinant human platelet-derived growth factor (rhPDGF-BB). Space maintenance for bone construct immobility and unimpeded wound healing was ensured via a nonresorbable titanium reinforced polytetrafluoroethylene membrane and an absorbable porcine collagen membrane.

RESULTS

Primary closure was maintained throughout the 6 month healing process at which time implant diagnostics commenced for prosthetically directed implant placement using dynamic navigation and involving soft tissue augmentation. Uncovery was performed 3 months thereafter leading to provisionalization and prosthetic phase completion.

CONCLUSION

This case report highlights a severe maxillary anterior ridge defect secondary to advanced peri-implantitis in a systemically healthy Caucasian male patient. The surgical outcome success, both clinically and radiographically, underscores the complexities of complete regional anatomy rehabilitation after suffering catastrophic and debilitating bone loss from inflammatory peri-implantitis. Further, it demonstrates the importance of incorporating optimized angiogenetic therapeutics to help establish a vascularized functional bone matrix for implant success.

Does guided level (fully or partially) influence implant placement accuracy at post-extraction sockets and healed sites? An in vitro study

OBJECTIVES

The aim of this study is to evaluate the effect of guide level on the accuracy of static computer-aided implant surgery (sCAIS) at post-extraction sockets and healed sites.

MATERIALS AND METHODS

A total of 30 duplicate dental models, with 300 potential implant sites, were used. All the models were equally randomized into three groups: fully guided (FG, n = 100), partially guided (PG, n = 100), and free handed (FH, n = 100) surgeries. After implant placement, the mean global, horizontal, depth, and angular deviations between the virtually planned and actual implant positions were measured automatically by a Python script within software Blender.

RESULTS

Both FG and PG surgeries showed significantly higher accuracy than FH surgery at post-extraction sockets and healed sites. In both sCAIS groups, there were nearly 50% more deviations from implants placed at sockets than those from delayed placement. For the immediate implant placement, the accuracy of sCAIS was significantly affected by the level of guidance. The FG group exhibited lower deviations than the PG group, with a significant difference in coronal global and horizontal deviations (p < .05). For the healed sites, two guided groups exhibited similar outcomes (p > .05).

CONCLUSIONS

sCAISs provide more accuracy than the free-handed approach in position transferring from planning to a model simulation. Full guidance can significantly increase the accuracy, especially at post-extraction sites.

CLINICAL RELEVANCE

Guided protocols showed significantly higher accuracy than free-handed surgery regardless of implantation timing, but both had nearly 50% more deviations in immediate implant placement.

Influence of Bone-Level Dental Implants Placement and of Cortical Thickness on Osseointegration: In Silico and In Vivo Analyses

The purpose of this research is to study the biomechanical response of dental implants in bone-level type locations, 0.5 mm above and below the bone level. In addition, the influence of the thickness of the cortical bone on osseointegration is determined due to the mechanical loads transfer from the dental implant to the cortical and trabecular bone. The thicknesses studied were 1.5 mm and 2.5 mm. Numerical simulations were performed using a finite element method (FEM)-based model. In order to verify the FEM model, the in silico results were compared with the results obtained from a histological analysis performed in an in vivo study with 30 New Zealand rabbits. FEM was performed using a computerized 3D model of bone-level dental implants inserted in the lower jawbone with an applied axial load of 100 N. The analysis was performed using different distances from the bone level and different thicknesses of cortical bone. The interface area of bone growth was evaluated by analyzing the bone–implant contact (BIC), region of interest (ROI) and total bone area (BAT) parameters obtained through an in vivo histological process and analyzed by scanning electron microscopy (SEM). Bone-level implants were inserted in the rabbit tibiae, with two implants placed per tibia. These parameters were evaluated after three or six weeks of implantation. FEM studies showed that placements 0.5 mm below the bone level presented lower values of stress distribution compared to the other studied placements. The lower levels of mechanical stress were then correlated with the in vivo studies, showing that this position presented the highest BIC value after three or six weeks of implantation. In this placement, vertical bone growth could be observed up the bone level. The smallest thickness of the study showed a better transfer of mechanical loads, which leads to a better osseointegration. In silico and in vivo results both concluded that the implants placed 0.5 mm below the cortical bone and with lower thicknesses presented the best biomechanical and histological behavior in terms of new bone formation, enhanced mechanical stability and optimum osseointegration.

Management and sequelae of dental implant removal

Inappropriate and unnecessary implant therapy driven by an erroneous belief that dental implants provide enhanced function and esthetics over diseased or failing teeth has led to a growing burden of implant complications across the globe. Specifically, esthetic and biological complications frequently lead to the unfavorable prognosis of dental implants. Often, these cannot be managed predictably to improve the condition or satisfy patients' demands. In such circumstances, implant removal needs to be considered. Currently, minimally invasive methods based on reverse torque engineering are key to preserve peri-implant soft and hard tissues. Implant replacement is now feasible, as evidenced by the high survival rates of implants placed at previously failed sites. Notwithstanding these data, clinicians should still consider carefully the expendability of an implant and whether its replacement will satisfy the prosthetic, biomechanical, and esthetic demands of the patient. In the scenario where future implant placement is desired, protocols undertaken for soft/hard tissue grafting and implant placement should be based upon defect morphology and soft and hard-tissue characteristics. Currently, however, a lack of knowledge of the biological events and dimensional changes that arise following implant removal renders decision-making complex and challenging, and recommendations remain largely based upon empirical speculation. This chapter will review the indications for implant replacement for prosthetic, biomechanical, and esthetic complications, alongside considerations in decision-making, planning, implementation, and outcomes of implant replacement.

Characteristics of Particles and Debris Released after Implantoplasty: A Comparative Study

Titanium particles embedded on peri-implant tissues are associated with a variety of detrimental effects. Given that the characteristics of these detached fragments (size, concentration, etc.) dictate the potential cytotoxicity and biological repercussions exerted, it is of paramount importance to investigate the properties of these debris. This study compares the characteristics of particles released among different implant systems (Group A: Straumann, Group B: BioHorizons and Group C: Zimmer) during implantoplasty. A novel experimental system was utilized for measuring and collecting particles generated from implantoplasty. A scanning mobility particle sizer, aerodynamic particle sizer, nano micro-orifice uniform deposit impactor, and scanning electron microscope were used to collect and analyze the particles by size. The chemical composition of the particles was analyzed by highly sensitive microanalysis, microstructures by scanning electron microscope and the mechanical properties by nanoindentation equipment. Particles released by implantoplasty showed bimodal size distributions, with the majority of particles in the ultrafine size range (<100 nm) for all groups. Statistical analysis indicated a significant difference among all implant systems in terms of the particle number size distribution (p < 0.0001), with the highest concentration in Group B and lowest in Group C, in both fine and ultrafine modes. Significant differences among all groups (p < 0.0001) were also observed for the other two metrics, with the highest concentration of particle mass and surface area in Group B and lowest in Group C, in both fine and ultrafine modes. For coarse particles (>1 µm), no significant difference was detected among groups in terms of particle number or mass, but a significantly smaller surface area was found in Group A as compared to Group B (p = 0.02) and Group C (p = 0.005). The 1 first minute of procedures had a higher number concentration compared to the second and third minutes. SEM-EDS analysis showed different morphologies for various implant systems. These results can be explained by the differences in the chemical composition and microstructures of the different dental implants. Group B is softer than Groups A and C due to the laser treatment in the neck producing an increase of the grain size. The hardest implants were those of Group C due to the cold-strained titanium alloy, and consequently they displayed lower release than Groups A and B. Implantoplasty was associated with debris particle release, with the majority of particles at nanometric dimensions. BioHorizons implants released more particles compared to Straumann and Zimmer. Due to the widespread use of implantoplasty, it is of key importance to understand the characteristics of the generated debris. This is the first study to detect, quantify and analyze the debris/particles released from dental implants during implantoplasty including the full range of particle sizes, including both micro- and nano-scales.

The psychobiological links between chronic stress-related diseases, periodontal/peri-implant diseases, and wound healing

Chronic stress is a relevant disease to periodontal practice, encompassing 25%-28% of the US population (American Psychological Association 2015). While it is well established that chronic psychologic stress can have significant deleterious systemic effects, only in recent decades have we begun to explore the biochemical, microbial, and physiologic impacts of chronic stress diseases on oral tissues. Currently, chronic stress is classified as a "risk indicator" for periodontal disease. However, as the evidence in this field matures with additional clinically controlled trials, more homogeneous data collection methods, and a better grasp of the biologic underpinnings of stress-mediated dysbiosis, emerging evidence suggests that chronic stress and related diseases (depression, anxiety) may be significant contributing factors in periodontal/peri-implant disease progression and inconsistent wound healing following periodontal-related therapeutics. Ideal solutions for these patients include classification of the disease process and de-escalation of chronic stress conditions through coping strategies. This paper also summarizes periodontal/implant-related therapeutic approaches to ensure predictable results for this specific patient subpopulation.

Principles of Combined Surgical Therapy for the Management of Peri-Implantitis

FOCUSED CLINICAL QUESTION

The purpose of this technical note is to present the principles for combined therapy as well as to illustrate the step-by-step approach of this procedure to efficiently manage peri-implantitis.

SUMMARY

Peri-implantitis is the primary threat that compromises the longevity of dental implants. This entity is regarded as a biofilm-mediated inflammatory condition. As such, the arrestment of disease is conditioned by the elimination of the etiological factor and the clinical resolution of inflammation by eliminating pathogenic pockets. It was suggested that the therapy of peri-implantitis relies upon defect configuration. In this sense, defect configuration is, in part, conditioned by the dimensions of the alveolar bone and implant position. In the clinical basis, it is frequent to identify combined defects exhibiting area(s) where reconstructive therapy is inefficient due to uncontained defect morphology. These situations represent clinical indications for combined therapy.

CONCLUSIONS

This therapeutic modality is based on the combination of reconstructive therapy in the infraosseous defect component and surface modification for the area of the implant within the supracrestal component or outside the reparative potential.

A commentary on strategic extraction

BACKGROUND

Advancements in strategies to maintain compromised teeth combined with a greater understanding of risks associated with dental implants invite a reassessment of the benefits of strategic extraction of a tooth with a questionable prognosis or of limited strategic value.

METHODS

Evidence of the management of compromised teeth and decision making for strategic extraction was reviewed. Additionally, the risks for peri-implantitis were evaluated from the perspective of patient centric, biologic, and biomechanical complications.

RESULTS

Recent clinical innovations support a more predictable maintenance of compromised dentition, and the clinical literature provides evidence of the risks associated with dental implants.

CONCLUSIONS

Because of the improvements in dental management of compromised dentition, strategic extraction should be deferred, whenever possible, to avoid complications associated with peri-implantitis.

Impact of collar laser microtexturing on peri-implant health and disease: a retrospective clinical study

OBJECTIVES

This retrospective study was aimed to compare the clinical and radiographic outcomes of implants with the same body design but different collar surface (laser-microtextured vs. not laser-microtextured) after functional loading.

MATERIALS AND METHODS

Forty-three patients (29 females, 14 males) with 139 implants (60 laser-microtextured and 79 without laser microtexturing) were included in this study. Patients were consecutively included, and the data were collected during their implant maintenance visit. Clinical and radiographic parameters including probing depth (PD), bleeding on probing (BoP), and marginal bone loss (MBL) were recorded. In addition, the implant success index (ISI) score was determined. Statistical analysis was performed using the Mann-Whitney U test, the Kruskal-Wallis rank test, or the Pearson χ² test, along with binary logistic regression (p < 0.05 was considered to be statistically significant).

RESULTS

The median post-loading follow-up was 24 months with 100% survival rate. There was no significant differences in terms of mean PD (3.01 mm vs. 2.63 mm), mean MBL (0.54 vs. 0.49 mm), BoP (56.7% vs. 53.2%), and ISI score between laser-microtextured collars and implants without laser microtexturing. Logistic regression revealed arch as a significant predictor of peri-implantitis (p = 0.02).

CONCLUSION

Within the limitations of this study, there was no statistically significant difference between the clinical and radiographic outcomes of implants with laser-microtextured and non-laser-microtextured collar designs. Clinical relevance Prospective studies with larger sample sizes and careful monitoring of implant placement protocols are needed for definite conclusions.

Risk factors, diagnosis and treatment of peri-implantitis: A cross-cultural comparison of U.S. and European periodontists' considerations

BACKGROUND

Peri-implantitis (PI) is a growing concern in the dental community worldwide. The study aimed to compare U.S. vs. European periodontists' considerations of risk factors, diagnostic criteria, and management of PI.

MATERIALS AND METHODS

393 periodontists from the U.S. and 100 periodontists from Europe (Germany, Greece, Netherlands) responded to anonymous surveys electronically or by mail.

RESULTS

Compared to U.S. periodontists, European respondents were younger, more likely to be female and placed fewer implants per month (9.12 vs. 13.90;p = 0.003). Poor oral hygiene, history of periodontitis, and smoking were considered as very important risk factors by both groups (rated >4 on 5-point scale). European periodontists rated poor oral hygiene (4.64 vs. 4.45;p = 0.005) and history of periodontitis (4.36 vs. 4.10;p = 0.006) as more important and implant surface (2.91 vs. 3.18;p = 0.023), occlusion (2.80 vs. 3.75;p<0.001) and presence of keratinized tissue (3.27 vs. 3.77;p<0.001) as less important than did U.S. periodontists. Both groups rated clinical probing, radiographic bone loss, and presence of bleeding and suppuration as rather important diagnostic criteria. They rated implant exposure/mucosal recession as relatively less important with U.S. periodontists giving higher importance ratings than European periodontists (3.99 vs. 3.54;p = 0.001). Both groups nearly always used patient education, plaque control and mechanical debridement when treating PI. U.S. periodontists were more likely to use antibiotics (3.88 vs. 3.07;p<0.001), lasers (2.11 vs. 1.68;p = 0.005), allograft (3.39 vs. 2.14;p<0.001) and regenerative approaches (3.57 vs. 2.56;p<0.001), but less likely to use resective surgery (3.09 vs. 3.53;p<0.001) than European periodontists.

CONCLUSIONS

U.S. and European periodontists' considerations concerning risk factors, diagnosis and management of PI were evidence-based. Identified differences between the two groups can inform future educational efforts. This article is protected by copyright. All rights reserved.

The question about the numerical value and quantitative data transfer of implant prosthodontics-orom experience guidance to digital guidance

The correct implant site design and placement are the basic clinical techniques that must be known for implant restoration. For a long time, most implants have been placed by free hands, and the choice of site is mostly dependent on the accumulation of long-term experience of the surgeon. The selection of implant site guided by this experience analogy logic is often based on the surgeon's level of experience,which often makes it very easy to produce complications related to the implant restoration of the incorrect site. In contrast, a clinical program using digital guidance and real-time measurable verification has emerged based on the restoration-oriented implantation concept, which marks the formation of an accurate, measurable and verifiable whole-process digital implant prototype. Furthermore, from the perspective of surveying, the numerical requirements that digital implant restoration relies on are actually incomplete to the four elements of measurement, which leading to the doubts about its authenticity. This article will question the numbers in implant restoration, and conduct a preliminary demonstration, and propose a new reliable actual measurement and verification method of the correct location and the numerical requirements of the restoration space and a new clinical program that relies on numbers from the perspective of the evolution of digital restoration, guided implantology and actual measurement technology. And this article further discusses the current mainstream implant restoration technology based on experience analogy which cannot effectively support the whole process of digital implant restoration and provides a new logical cognitive basis for the final realization of the entire process of digital implant restoration.

Osteogenic and Regenerative Potential of Free Gingival Graft

We studied immunolocalization of CD29, CD44, osteocalcin, and TGF-β1 in the bone tissue of the mandible of miniature pigs with extra-bone fixation of a free gingival graft. Three months after surgery, neoosteogenesis foci with high expression of the studied markers were found in the contact area of the free gingival graft with the alveolar bone. The markers were localized in the layer of external circumferential lamellae, on the surface of concentric lamellae of the growing osteons, and in the connective tissue of the Haversian canals. TGF-β1-immunopositive cells predominated in the connective tissue of the Haversian and Volkmann canals and in the adventitia and inner lining of the vascular wall. The established morphochemical patterns of osteogenous cells indicate significant reparative capabilities of a free gingival graft and allows considering it as an effective osteoinductive factor.

Effects of combined use of recombinant human fibroblast growth factor-2 and β-tricalcium phosphate on ridge preservation in dehiscence bone defects after tooth extraction: A split-mouth study in dogs

BACKGROUND AND OBJECTIVE

Following tooth extraction, bone resorption is especially severe in cases complicated with buccal dehiscence bone defects. To minimize this, various bone graft materials have been used for alveolar ridge preservation. This study aimed to evaluate additional effects of the concomitant use of recombinant human fibroblast growth factor-2 (rhFGF-2) with β-tricalcium phosphate (β-TCP) on ridge preservation in a dehiscence defect model after tooth extraction in dogs.

MATERIALS AND METHODS

The maxillary first premolars of six beagle dogs were extracted and dehiscence defects of 4 × 4 × 5 mm (mesio-distal width × bucco-palatal width × depth) were created. Bilateral defects were filled with β-TCP combined with 0.3% (w/v) rhFGF-2 (test sites) or the scaffold alone (control sites). Twelve weeks post-surgery, histologic and histometric evaluations were performed.

RESULTS

Morphological measurements using micro-computed tomography revealed a significantly greater bone volume at the test sites (48.9 ± 9.06 mm³ ) than at the control sites (38.8 ± 7.24 mm³ ). Horizontal widths of the alveolar ridge at the coronal and middle position at the test sites (2.18 ± 0.71 mm, 2.93 ± 0.53 mm) were significantly greater than those at the control sites (1.47 ± 0.41 mm, 2.36 ± 0.45 mm, respectively). Regarding the histological parameters, the occupation rate of mineralized bone in the original defects was slightly higher at the test sites (44.07 ± 10.19%) than that at the control site (41.15 ± 6.56%).

CONCLUSIONS

These results indicate that the adjunct use of rhFGF-2 with β-TCP is effective for alveolar ridge preservation in fresh extraction sockets with dehiscence defects.

Impact of mucosal phenotype on marginal bone levels around tissue level implants: A prospective controlled trial

BACKGROUND

The aim of this 1-year prospective clinical trial was to compare clinical parameters and marginal bone levels (MBLs) around tissue level implants with a partially smooth collar between patients with thin (≤2 mm) and thick (>2 mm) vertical mucosal phenotypes.

METHODS

Thirty patients needing a single dental implant were recruited and allocated to thin (n = 14) or thick (n = 16) phenotype groups. Post-restoration, clinical (probing depth, recession, width of keratinized mucosa, bleeding on probing, suppuration, implant mobility, plaque index, and gingival index) and radiographic bone level measurements were recorded at different timepoints for 1 year.

RESULTS

Twenty-six patients (13 per group) completed the 1-year examination. No implants were lost (100% survival rate). There were no significant differences (P >0.05) between thin and thick vertical mucosal phenotypes for any clinical parameter or for the radiographic MBL.

CONCLUSIONS

Tissue level implants at 1 year of function placed in thin vertical mucosa achieved similar clinical parameters and radiographic MBLs as those in thick tissue. The formation of the peri-implant supracrestal tissue height plays a key role in MBL than mucosal thickness in tissue level implant.

Decontamination of Ti Oxide Surfaces by Using Ultraviolet Light: Hg-Vapor vs. LED-Based Irradiation

C-range Ultraviolet (UVC) mercury (Hg)-vapor lamps have shown the successful decontamination of hydrocarbons and antimicrobial effects from titanium surfaces. This study focused on surface chemistry modifications of titanium dental implants by using two different light sources, Hg-vapor lamps and Light Emitting Diodes (LEDs), so as to compare the effectivity of both photofunctionalization technologies. Two different devices, a small Hg-vapor lamp (λ = 254 nm) and a pair of closely placed LEDs (λ = 278 nm), were used to irradiate the implants for 12 min. X-ray Photoelectron Spectroscopy (XPS) was employed to characterize the chemical composition of the surfaces, analysing the samples before and after the lighting treatment, performing a wide and narrow scan around the energy peaks of carbon, oxygen and titanium. XPS analysis showed a reduction in the concentration of surface hydrocarbons in both UVC technologies from around 26 to 23.4 C at.% (carbon atomic concentration). Besides, simultaneously, an increase in concentration of oxygen and titanium was observed. LED-based UVC photofunctionalization has been suggested to be as effective a method as Hg-vapor lamps to remove the hydrocarbons from the surface of titanium dental implants. Therefore, due to the increase in worldwide mercury limitations, LED-based technology could be a good alternative decontamination source.

Functionalized Scaffold and Barrier Membrane with Anti-BMP-2 Monoclonal Antibodies for Alveolar Ridge Preservation in a Canine Model

Introduction

The aim of this study was to investigate the ability of anti-bone morphogenetic protein 2 monoclonal antibody (anti-BMP-2 mAb) to functionalize scaffolds to mediate bone regeneration in a canine model.

Materials and Methods

The mandibular right premolar 4 (PM4) was extracted in eight beagle dogs and grafted with anti-BMP-2 mAb+anorganic bovine bone mineral with 10% collagen (ABBM-C) and porcine bilayer native collagen membrane (CM). The ABBM-C and CM were functionalized with either anti-BMP-2 mAb (test group) or an isotype matched control mAb (control group). Animals were euthanized at 12 weeks for radiographic, histologic, and histomorphometric analyses. Outcomes were compared between groups.

Results

3D imaging using cone beam computed tomography (CBCT) revealed that sites treated with ABBM-C and CM functionalized with anti-BMP-2 mAb exhibited significantly more remaining bone width near the alveolar crest, as well as buccal bone height, compared with control groups. Histologic and histomorphometric analyses demonstrated that in anti-BMP-2 mAb-treated sites, total tissue volume was significantly higher in the coronal part of the alveolar bone crest compared with control sites. In anti-BMP-2 mAb-treated sites, bone formation was observed under the barrier membrane.

Conclusion

Functionalization of the ABBM-C scaffold and CM appeared to have led to bone formation within healing alveolar bone sockets.

Self-administered proximal implant-supported hygiene measures and the association to peri-implant conditions

BACKGROUND

Dental plaque biofilm is considered to be the underlying cause of peri-implant diseases. Moreover, it has been corroborated recently the association between the presence of these diseases and deficiently designed implant-supported prostheses. In this regard, professional-administered oral hygiene measures have been suggested to play a dominant role in prevention.

METHODS

A cross-sectional study was conducted in dental implant patients according to accessibility for self-performed oral hygiene using a 0.5 mm interproximal brush. Periodontal and peri-implant status were assessed based on clinical and radiographic variables to determine the prevalence of peri-implant diseases. In addition, the participants completed a questionnaire on the efficiency and accessibility for self-performed proximal hygiene. Associations of descriptive data were analyzed using the chi-squared test and Mann-Whitney U-test. Correlations of the variables with the primary outcome (accessibility) were assessed by means of generalized estimation equations and multilevel logistic regression models.

RESULTS

Based on an a priori power calculation, a total of 50 patients (171 implants) were consecutively recruited. From these, 46% of the prostheses allowed proper access for performing proximal hygiene whereas 54% of the prostheses precluded proper access. Poor access for proximal hygiene displayed tendency towards statistical significance with peri-implant disease (OR = 2.31; P = 0.090), in particular with peri-implant mucositis (OR = 2.43; P = 0.082) when compared to good access. In addition, an association was observed to increased levels of mucosal redness (P = 0.026) and the full-mouth bleeding score (P = 0.018). On the other hand, the presence of peri-implant disease was related to self-reported assessment of oral hygiene measures (P = 0.015) and to patient perception of gingival/mucosal bleeding when performing oral hygiene (P = 0.026). In turn, the diagnosis of peri-implant disease was significantly associated to the quantity and quality of information provided at the time of implant therapy (P = 0.004), including the influence of confounders upon disease occurrence (P = 0.038) CONCLUSIONS: To a certain extent, accessibility for self-performed proximal hygiene is associated to the peri-implant condition. On the other hand, the information received by the patient from the dental professional is essential for self-monitoring of the peri-implant conditions and for alerting to the possible presence of disorders.

The fate of the distal papilla around tooth-bound implant-supported restorations in maxillary central incisor sites

The distal papilla around tooth-bound implant-supported restorations in maxillary central incisor sites tends to exhibit an atrophied aspect after tissue maturation following the delivery of the final prosthesis. This article provides an explanation to this phenomenon, as well as a set of therapeutic considerations to minimize its occurrence and optimize the outcomes of tooth replacement therapy with dental implants in this specific anatomic location.

Clinical Decision Making for Primary Peri-Implantitis Prevention: Practical Applications

FOCUSED CLINICAL QUESTION

When planning dental implant therapy, what risk-reduction strategies allow practitioners to select patients, sites, and restorative plans that decrease the incidence of peri-implant disease?

SUMMARY

With a marked increase in the number of patients receiving dental implants to treat partial or complete edentulism, it follows that the prevalence of peri-implant mucositis and peri-implantitis have increased. Risks associated with implant therapies may vary based upon underlying local, environmental, surgical, patient, prosthetic, and fixture-related factors. Furthermore, an emphasis on preventative measures and maintenance should be undertaken to avoid development and progression of peri-implant diseases. Thorough risk assessment, proper treatment planning, and early diagnosis and intervention are critical in the absence of definitive data of long-term success of treatments for peri-implant condition. Given the difficulty in intervention once peri-implantitis is established, identification of risk factors and development of treatment plans to address those factors before dental implant therapy is critical to the long-term health and success of dental implants.

CONCLUSIONS

A patient-centered, evidence based approach to dental implant treatment planning to reduce the risk for peri-implantitis should be undertaken. Systematic diagnosis of disease state(s) and evaluation of the etiologic and modifying risk factors for peri-implant diseases can yield more optimal outcomes to reduce peri-implantitis rates.

Effect of different implant placement depths on crestal bone levels and soft tissue behavior: A 5-year randomized clinical trial

OBJECTIVES

This randomized clinical trial analyzed the long-term (5-year) crestal bone changes and soft tissue dimensions surrounding implants with an internal tapered connection placed in the anterior mandibular region at different depths (equi- and subcrestal).

MATERIALS AND METHODS

Eleven edentulous patients were randomly divided in a split-mouth design: 28 equicrestal implants (G1) and 27 subcrestal (1-3 mm) implants (G2). Five implants were placed per patient. All implants were immediately loaded. Standardized intraoral radiographs were used to evaluate crestal bone (CB) changes. Patients were assessed immediately, 4, 8, and 60 months after implant placement. The correlation between vertical mucosal thickness (VMT) and soft tissue recession was analyzed. Sub-group analysis was also performed to evaluate the correlation between VMT and CB loss. Rank-based ANOVA was used for comparison between groups (α = .05).

RESULTS

Fifty-five implants (G1 = 28 and G2 = 27) were assessed. Implant and prosthetic survival rate were 100%. Subcrestal positioning resulted in less CB loss (-0.80 mm) when compared to equicrestal position (-0.99 mm), although the difference was not statistically significant (p > .05). Significant CB loss was found within the G1 and G2 groups at two different measurement times (T4 and T60) (p < .05). Implant placement depths and VMT had no effect on soft tissue recession (p > .05).

CONCLUSIONS

There was no statistically significant difference in CB changes between subcrestal and equicrestal implant positioning; however, subcrestal position resulted in higher bone levels. Neither mucosal recession nor vertical mucosa thickness was influenced by different implant placement depths.

Peri-implantitis

OBJECTIVES

This narrative review provides an evidence-based overview on peri-implantitis for the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

METHODS

A literature review was conducted addressing the following topics: 1) definition of peri-implantitis; 2) conversion from peri-implant mucositis to peri-implantitis, 3) onset and pattern of disease progression, 4) characteristics of peri-implantitis, 5) risk factors/indicators for peri-implantitis, and 6) progressive crestal bone loss in the absence of soft tissue inflammation.

CONCLUSIONS

1)Peri-implantitis is a pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant connective tissue and progressive loss of supporting bone. 2)The histopathologic and clinical conditions leading to the conversion from peri-implant mucositis to peri-implantitis are not completely understood. 3)The onset of peri-implantitis may occur early during follow-up and the disease progresses in a non-linear and accelerating pattern. 4a)Peri-implantitis sites exhibit clinical signs of inflammation and increased probing depths compared to baseline measurements. 4b)At the histologic level, compared to periodontitis sites, peri-implantitis sites often have larger inflammatory lesions. 4c)Surgical entry at peri-implantitis sites often reveals a circumferential pattern of bone loss. 5a)There is strong evidence that there is an increased risk of developing peri-implantitis in patients who have a history of chronic periodontitis, poor plaque control skills, and no regular maintenance care after implant therapy. Data identifying "smoking" and "diabetes" as potential risk factors/indicators for peri-implantitis are inconclusive. 5b)There is some limited evidence linking peri-implantitis to other factors such as: post-restorative presence of submucosal cement, lack of peri-implant keratinized mucosa and positioning of implants that make it difficult to perform oral hygiene and maintenance. 6)Evidence suggests that progressive crestal bone loss around implants in the absence of clinical signs of soft tissue inflammation is a rare event.

Peri-implantitis

OBJECTIVES

This narrative review provides an evidence-based overview on peri-implantitis for the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

METHODS

A literature review was conducted addressing the following topics: 1) definition of peri-implantitis; 2) conversion from peri-implant mucositis to peri-implantitis, 3) onset and pattern of disease progression, 4) characteristics of peri-implantitis, 5) risk factors/indicators for peri-implantitis, and 6) progressive crestal bone loss in the absence of soft tissue inflammation.

CONCLUSIONS

1)Peri-implantitis is a pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant connective tissue and progressive loss of supporting bone. 2)The histopathologic and clinical conditions leading to the conversion from peri-implant mucositis to peri-implantitis are not completely understood. 3)The onset of peri-implantitis may occur early during follow-up and the disease progresses in a non-linear and accelerating pattern. 4a)Peri-implantitis sites exhibit clinical signs of inflammation and increased probing depths compared to baseline measurements. 4b)At the histologic level, compared to periodontitis sites, peri-implantitis sites often have larger inflammatory lesions. 4c)Surgical entry at peri-implantitis sites often reveals a circumferential pattern of bone loss. 5a)There is strong evidence that there is an increased risk of developing peri-implantitis in patients who have a history of chronic periodontitis, poor plaque control skills, and no regular maintenance care after implant therapy. Data identifying "smoking" and "diabetes" as potential risk factors/indicators for peri-implantitis are inconclusive. 5b)There is some limited evidence linking peri-implantitis to other factors such as: post-restorative presence of submucosal cement, lack of peri-implant keratinized mucosa and positioning of implants that make it difficult to perform oral hygiene and maintenance. 6)Evidence suggests that progressive crestal bone loss around implants in the absence of clinical signs of soft tissue inflammation is a rare event.

Influence of implant neck and abutment characteristics on peri-implant tissue health and stability. Oral reconstruction foundation consensus report

OBJECTIVE

The aim of this consensus meeting was to assess the influence of implant neck and abutment characteristics on peri-implant tissue health and stability.

MATERIAL AND METHODS

Group and plenary discussions were based on two systematic reviews focusing on the effect of titanium implants with different collar designs/surface modifications and the abutment material on the stability of marginal bone levels (MBLs), peri-implant health, and survival rates.

RESULTS

The changes in MBLs were not influenced by the abutment material and were also similar at one- and two-piece implants after one year of loading. Rough collar implants improved MBLs in comparison to machined collar implants. Additional modifications of the collar had no beneficial clinical effect on MBLs. Titanium abutments were associated with significantly higher increases in bleeding on probing when compared with zirconia abutments.

CONCLUSION

MBLs are mainly influenced by the microstructure (i.e., rough surfaced) of the implant neck. Consensus statements and specific recommendations for future research were elaborated during the consensus meeting.

Understanding Peri-Implantitis as a Plaque-Associated and Site-Specific Entity: On the Local Predisposing Factors

The prevalence of implant biological complications has grown enormously over the last decade, in concordance with the impact of biofilm and its byproducts upon disease development. Deleterious habits and systemic conditions have been regarded as risk factors for peri-implantitis. However, little is known about the influence of local confounders upon the onset and progression of the disease. The present narrative review therefore describes the emerging local predisposing factors that place dental implants/patients at risk of developing peri-implantitis. A review is also made of the triggering factors capable of inducing peri-implantitis and of the accelerating factors capable of interfering with the progression of the disease.

Macrophage polarization in aseptic bone resorption around dental implants induced by Ti particles in a murine model

BACKGROUND AND OBJECTIVES

Titanium particles/ions detected in peri-implant tissues have been considered as a potential etiologic factor for crestal bone loss around oral implants. However, the definite impact of titanium wear particles on the health of surrounding structures remains undetermined. The purpose of this study was to investigate the effects of titanium particles-induced foreign body reaction on peri-implant bone level and the related mechanism by using clodronate liposomes to deplete macrophages.

MATERIAL AND METHODS

Sprague Dawley rats with custom-made titanium screw implanted in bilateral maxillary first molar area for 4 weeks to obtain osseointegration were randomly divided into four groups. Twenty microgram titanium particles were introduced into the peri-implant tissue to induce aseptic foreign body reaction, and macrophages were depleted by the local injection of 100 μL clodronate liposome immediately and re-injection every 3 days until the sacrifice of the rats (Ti + LipClod group). Titanium-injected rats also treated with phosphate buffer solution (Ti + PBS) or empty liposome (Ti + Lip) as well as rats injected with PBS alone (Control) were included as controls. Eight weeks later, animals were sacrificed and samples containing implants were collected. Half of the samples were analyzed radiologically to measure bone level change, and macrophage markers (CD68, CCR7, CD163) was also characterized by immunofluorescence to evaluate macrophage number, density, and phenotype distribution (CCR7+M1/CD163+M2). The rest of the samples were used to determine the relative mRNA expression levels of TNF-α, IL-1β, IL-6, and RANKL with real-time PCR analysis.

RESULTS

No obvious bacterial contamination was found in all titanium-injected areas, and the implant survival rate was 100% with no implant loss. Compared with Ti + PBS and Ti + Lip group, macrophage density (1.64 ± 0.86%) infiltrated into peri-implant tissue and bone loss (0.17 ± 0.03 mm) around implant decreased significantly in the Ti + LipClod group. Immunofluorescence analysis showed that more macrophage infiltrated into peri-implant tissue in the Ti + PBS and Ti + Lip groups, predominantly with M1 phenotype. In contrast, the macrophage density was lower and M2 phenotype was dominant in the Control group, while macrophages density was significantly reduced and the M1 type macrophages were slightly more than M2 type in the Ti + LipClod group. Accordingly, TNF-α, IL-1β, IL6, and RANKL mRNA expression increased significantly in the Ti + PBS and Ti + Lip groups compared with Control and Ti + LipClod groups.

CONCLUSIONS

Titanium particles had a negative effect on peri-implant tissue by activating macrophages which induced an M1 macrophage phenotype promoting local secretion of inflammatory cytokines. It was found that clodronate liposome treatment attenuated the severity of inflammation and bone loss by depletion of macrophages. Therefore, the present study revealed the marked impact of macrophage polarization with respect to peri-implant bone loss caused by titanium particles.

Clinical outcomes and cost effectiveness of computer-guided versus conventional implant-retained hybrid prostheses: A long-term retrospective analysis of treatment protocols

BACKGROUND

Computer-guided systems were developed to facilitate implant placement at optimal positions in relation to the future prosthesis. However, the time, cost and, technique sensitivity involved with computer-guided surgery impedes its routine practice. The aim of this study is to evaluate survival rates and complications associated with computer-guided versus conventional implant placement in implant-retained hybrid prostheses. Furthermore, long-term economic efficiency of this approach was assessed.

METHODS

Patients were stratified according to implant placement protocol into a test group, using computer-guided placement, and a control group, using traditional placement. Calibrated radiographs were used to measure bone loss around implants. Furthermore, the costs of the initial treatment and prosthetic complications, if any, were standardized and analyzed.

RESULTS

Forty-five patients (149 implants in the test group and 111 implants in the control group) with a minimum follow-up of 5 years, and a mean follow-up of 9.6 years, were included in the study. While no significant difference was found between both groups in terms of biologic and technical complications, lower incidence of implant loss was observed in the test group (P < 0.001). A statistically significant difference in favor of the non-guided implant placement group was found for the initial cost (P < 0.05) but not for the prosthetic complications and total cost (P > 0.05).

CONCLUSIONS

Computer-guided implant placement for an implant-supported hybrid prosthesis is a valid, reliable alternative to the traditional approach for implant placement and immediate loading. Computer-guided implant placement showed higher implant survival rates and comparable long-term cost to non-guided implant placement.

Prevalence and risk indicators of peri-implantitis in Korean patients with a history of periodontal disease: a cross-sectional study

Purpose

The aim of this study was to analyze the prevalence and risk indicators of peri-implantitis in Korean patients with history of periodontal disease.

Methods

A total of 444 patients with 1,485 implants were selected from patients who had been treated at the Department of Periodontology, Chonbuk National University Dental Hospital between July 2014 and June 2015. A group with a history of peri-implantitis (HP) (370 patients with 1,189 implants) and a group with a current peri-implantitis (CP) (318 patients with 1,004 implants) were created based on the radiographic and clinical assessments of implants. The prevalence of peri-implantitis was calculated at both the patient and implant levels. The influence of risk variables on the occurrence of peri-implantitis was analyzed using generalized estimating equations analysis.

Results

The prevalence of peri-implantitis in the HP and CP groups ranged from 6.7% to 19.7%. The cumulative peri-implantitis rate in the HP group estimated with the Kaplan-Meier method was higher than that in the CP group over the follow-up period. Among the patient-related risk variables, supportive periodontal therapy (SPT) was the only significant risk indicator for the occurrence of peri-implantitis in both groups. In the analysis of implant-related variables, implants supporting fixed dental prosthesis (FDP) and implants with subjective discomfort were associated with a higher prevalence of peri-implantitis than single implants and implants without subjective discomfort in the HP group. The presence of subjective discomfort was the only significant implant-related variable predictive of peri-implantitis in the CP group.

Conclusions

Within the limitations of this study, the prevalence of peri-implantitis in Korean patients with a history of periodontal disease was similar to that reported in other population samples. Regular SPT was important for preventing peri-implantitis. Single implants were found to be less susceptible to peri-implantitis than those supporting FDP. Patients' subjective discomfort was found to be a strong risk indicator for peri-implantitis.

Bone Inflammation, Bone Infection and Dental Implants Failure: Histological and Cytological Aspects Related to Cement Excess

Background: Dental implant failure can recognize several causes and many of them are quite preventable with the right knowledge of some clinical critical factors. Aim of this paper is to investigate about the histological aspects related to dental implants failure in such cases related to cement excess, how such histological picture can increase the risk of bacterial infections and how the different type of cement can interact with osteoblasts in-vitro. Methods: We randomly selected 5 patients with a diagnosis of dental implant failure requiring to be surgically removed: in all patients was observed an excess of dental cement around the failed implants. Histological investigations were performed of the perimplant bone. Cell culture of purchased human Osteoblasts was performed in order to evaluate cell proliferation and cell morphology at 3 time points among 3 cement types and a control surface. Results: Dental cement has been related to a pathognomonic histological picture with a foreign body reaction and many areas with black particles inside macrophage cells. Finally, cell culture on different dental cements resulted in a lower osteoblasts survival rate. Conclusions: It is appropriate that the dentist puts a small amount of dental cement in the prosthetic crown, so to avoid the clinical alterations related to the excess of cement.

Risk Factors for Peri-Implantitis: Effect of History of Periodontal Disease and Smoking Habits. A Systematic Review and Meta-Analysis

Objectives

The purpose of this review was to evaluate whether history of periodontitis and smoking habits could represent a risk factor for peri-implantitis and implant loss.

Material and Methods

This systematic review followed PRISMA guidelines and was registered at the PROSPERO database [registration numbers CRD42016034160 (effect of history of periodontitis) and CRD42016033676 (effect of smoking)]. Broad electronic (MEDLINE) and manual searches were conducted among articles published from January 1^st 1990 up to December 31^st 2015, resulting in 49332 records for history of periodontitis and 3199 for smoking habits. Selection criteria included prospective studies comparing two cohorts of patients, with and without the investigated risk factor, with a minimum follow-up period of three years, and reporting data on peri-implantitis and implant loss occurrence. Considering that only prospective studies were included, dichotomous data were expressed as risk ratios and 95% confidence intervals.

Results

Three studies evaluating history of periodontitis (on which quantitative analysis was performed) and one study on smoking effect were included. Both implant and patient-based meta-analyses revealed a significantly higher risk of developing peri-implantitis in patients with a history of periodontitis compared with periodontally healthy subjects, but not a statistically significant increased risk for implant loss.

Conclusions

The outcomes of this systematic review indicate history of periodontitis as a possible risk factor for peri-implantitis, while insufficient data are present in literature to evaluate the role of smoking. However, available evidence is still weak and immature, and sound epidemiological studies are needed to analyse the specific contribution of these potential risk factors.