Peri-implant diseases: diagnosis and risk indicators

Retrospective Study of the Association between Peri-Implantitis and Keratinized Mucosa

1. Background: Peri-implantitis affects a high percentage of patients treated with dental implants. Among the risk factors that can cause this pathology, limited evidence exists regarding the absence of keratinized mucosa. The main objective of this study was to compare the amount of keratinized mucosa around healthy implants versus implants in patients with peri-implantitis, in order to analyze its influence on esthetics and the development of this pathology, and to study the possible influence of keratinized mucosa on various clinical parameters. 2. Methods: A retrospective case-control study was carried out in which 203 implants were evaluated, 103 of which presented a healthy peri-implant state, versus 100 which had peri-implantitis. The following elements were recorded: keratinized mucosa, recession, plaque index, bleeding, suppuration, probing depth, and bone level. 3. Results: Keratinized mucosa was present in 51% of the peri-implantitis group versus 97.1% of the healthy implants. In implants without keratinized mucosa, both recession and plaque index, bleeding on probing (96.2%), suppuration (57.7%), mean probing depth and bone level were higher. Implants without keratinized mucosa presented worse esthetics. 4. Conclusions: Absence of Keratinized mucosa around dental implants seems to be associated with the appearance of peri-implantitis modifying certain clinical parameters: there is a greater probability of recession, bleeding, suppuration, deficient hygiene, greater probing depth and greater bone loss in implants without keratinized mucosa.

Association between IL-1A, IL-1B and IL-1RN Polymorphisms and Peri-Implantitis: A Systematic Review and Meta-Analysis

Recent studies report that individuals with polymorphisms in the genes that encode for interleukin (IL)-1α and IL-1β (IL-1A and IL1B, respectively) and for IL-1 receptor antagonist (IL-1RN) may be more susceptible in developing peri-implantitis. Therefore, the current systematic review evaluates what is reported about the role of genetics, more specifically of single nucleotide polymorphisms (SNP) on IL-1 and variable number of tandem repeats (VNTR) on IL-1RN, in the development of peri-implantitis. This systematic review was carried out by screening PubMed, B-on, Cochrane and Scopus databases, for articles English, Spanish, and Portuguese, with no limit regarding the publication year. Eight articles were selected for systematic review and four for meta-analytic syntheses. Our results show that although there is a lack of consensus in the literature, there seems to be an association between IL-1A, IL-1B, and IL-1RN polymorphisms with peri-implantitis. The results of the meta-analysis showed that patients who have the polymorphic allele at position +3954 of the IL-1B gene have on average almost twice the risk of developing peri-implantitis (odds ratio = 1.986, 95% confidence interval).

The accuracy of probing, ultrasound and cone-beam CT scans for determining the buccal bone plate dimensions around oral implants - A systematic review

OBJECTIVE

The objective of this review was to assess the accuracy of available means of determining the BBT (buccal bone thickness) and/or BBL (buccal bone level). This was translated into the following research question: What is the accuracy of the available means of visualizing the BBP (buccal bone plate) to establish the BBT and/or the BBL, when compared to control measurements? As control measurements histomorphometric measurements, direct measurements and cone-beam computed tomography (CBCT) measurements in the absence of metal are accepted.

BACKGROUND DATA

METHODS: The literary search was performed by searching the databases of MEDLINE, Embase, and Web of Science, up to July 13, 2021. Types of studies included were clinical, in vitro and animal trials, specifically looking into the bone level and/or bone thickness of the buccal bone plate at oral implants. Reference lists were hand searched for relevant articles. Two reviewers performed the data extraction and analysis. Only studies using reliable control measurements to evaluate the accuracy of the tested means of visualizing BBT and/or BBL were included for analysis. The QUADAS-2 tool was used to perform bias analysis on the relevant studies. Extracted data was tabulated to show the differences between test and control measurements for BBT and BBL. For in vitro studies on CBCT measurements of BBT meta-analysis could be performed.

RESULTS

A total of 1176 papers were identified in the search. Twenty-two articles were used for data extraction and qualitative analysis. Of these studies nine were animal studies, 9 were in vitro studies and four were human studies. Six animal studies and three human studies provided data on probing. CBCT and sonography as techniques for visualizing the buccal bone plate. Probing at implant sites seems to provide data that correlates with a consistent distance from the BBP. Meta-analysis for probing studies could not be performed due to heterogeneity in the setups of these studies. Eleven studies on CBCT were eligible for inclusion. Of these three were animal studies, the remaining 8 studies were all in vitro studies. Meta-analysis was performed on the accuracy of CBCT for in vitro studies, finding a significant underestimation of the BBT when compared to control measurements by a mean difference of -0.15 mm with 95%CI [-0.26,-0.03]. Three studies were identified on measurement of BBT and/or BBL by sonography. This included one human study and two in vitro studies. The identified studies show a low error when determining the buccal bone level or thickness using sonography. All included studies possess a high risk of bias according to risk of bias analysis, mostly due to selection of the patient.

CONCLUSION

A strong limitation of this systematic review is the inclusion of different studies with heterogeneous designs. Within the limits of this analysis it cannot be concluded that probing is an accurate way of visualizing the BBP. CBCT cannot yet be recommended as a standard diagnostic tool for follow-up of the BBP at oral implants. The application of sonography as a diagnostic tool to visualize the BBP needs further scientific validation.

Horizontal ridge augmentation in the anterior maxilla with in situ onlay bone grafting: a retrospective cohort study

OBJECTIVES

This study aimed to introduce a digitally guided in situ autogenous onlay grafting technique and compare its effectiveness with the conventional (ex situ) onlay technique in augmenting horizontal bone defects of the anterior maxilla.

MATERIALS AND METHODS

This retrospective cohort study included 24 patients who had received autogenous onlay bone grafts combined with guided bone regeneration (GBR) in the anterior maxilla. Fourteen patients were recruited into the in situ onlay grafting group (EG), and 10 were recruited into the ex situ onlay group (CG), defined by the donor sites. The clinical parameters, radiographic changes, micro-CT, and histological processes were evaluated after a mean follow-up period of 1.7 years.

RESULTS

The horizontal bone width reflected significant bone modeling over time (p < 0.001) in the first 6 months. Multivariable analysis showed that the treatment modality (grouping) was a critical factor positively associated with vertical bone height alteration. However, neither the alteration rate of horizontal bone width nor the bone volume was associated with the treatment modality. The number of periosteal screws per graft positively affected horizontal contour maintenance (p < 0.05). No significant differences were observed between the groups in the clinical parameters (complications, success rate, and peri-implant parameters). The micro-CT and histological outcomes were similar between the groups.

CONCLUSION

Despite the limitations of this study, in situ onlay grafting combined with GBR was an effective and reliable approach for horizontal bone augmentation in the anterior maxilla and appeared to demonstrate better stability in vertical bone remodeling.

CLINICAL RELEVANCE

This study introduces a modified and minimally invasive technique of onlay grafting for horizontal bone augmentation. This in situ onlay grafting demonstrates superior stability in vertical bone remodeling. The trial registration number is ChiCTR2100054683.

Does Root Development Status Affect the Outcome of Tooth Autotransplantation? A Systematic Review and Meta-Analysis

Background: Tooth autotransplantation is defined as the surgical repositioning of an autogenous tooth in another surgical site within the same individual. Aim: The aim of this research was to analyze the outcome of tooth transplantation using immature donor teeth compared with closed apex teeth and to compare differences between donor tooth positions on the arch. Methods: Electronic and manual literature searches were performed in different databases, including the National Library of Medicine (MEDLINE), EMBASE (OVID), Cochrane Central (CENTRAL), and the digital library of the Universitat Internacional de Catalunya (UIC University) from 1978 to March 2021. Studies were selected when they fulfilled the following criteria: only human prospective clinical studies, minimum sample size of 10 patients, minimum follow-up of 1 year, studies reporting or with at least deducible data on survival rates, immediate tooth autotransplantation with completed or incomplete root formation, and publications in the English language. A meta-analysis of random effects was developed to estimate the global effect measure of the survival rate, success rate, and root resorption involving the total sample, as well as open- and closed-apex groups. Results: Twenty-four articles were eligible for analysis. The Cohen’s kappa corresponding to this review was 0.87, and the risk assessment was considered low–moderate for the included studies. Overall survival and success rates were 95.9% and 89.4%, respectively, with a mean follow-up of 4 years and an overall mean age of 25.2 ± 12.3 years. Closed apex teeth showed a survival rate of 3.9% lower than that of open apex teeth. Higher complication rates were found for both inflammatory external root resorption and replacement root resorption in the closed-apex group, without reaching statistical significance. Conclusions: Tooth autotransplantation is a viable treatment alternative, regardless of the apical condition, with high survival and success rates after a mean follow-up of 4 years. Open-apex donor teeth could be considered the gold-standard option, showing lower complication rates when compared to closed-apex donor teeth. Future randomized controlled clinical studies are needed to examine the long-term prognosis of this technique.

The long-term impact of alveolar ridge preservation with xenograft bone mineral on peri-implant health after 5 years in function: A retrospective cohort study of 108 patients assessed clinically and radiologically

Objectives

When teeth are lost, dental implants contribute to improved oral function and quality of life. Limitations in dental implant placement arising from poor bone anatomy may be circumvented via alveolar ridge preservation (ARP). The aim is to evaluate the long‐term impact of ARP on peri‐implant health and the relationship with common risk indicators such as smoking and history of periodontitis.

Materials and Methods

One hundred and eight patients were enrolled in this retrospective cohort study with 308 implants. Of these, ∼41% were placed in bone sites that had previously received ARP with deproteinized bovine bone mineral xenograft. Association between baseline variables: ARP, age, gender, number of implants per patient, anatomical site, smoking, and previous history of grade III/IV periodontitis, and outcome variables: mucositis, peri‐implantitis, implant loss, full‐mouth plaque score (FMPS), full‐mouth bleeding score, and marginal bone loss (MBL) was evaluated using both univariate and multivariate models.

Results

After 5 years, the overall survival rate was 93.7%. The occurrence of peri‐implantitis was 21.3% and the extent of MBL was ~2.2 mm. Both peri‐implantitis occurrence and MBL were comparable between ARP⁺ and ARP⁻. Smoking is associated with higher FMPS and MBL.

Conclusions

The findings indicate that peri‐implant health can be maintained around dental implants for up to 5 years in ARP⁺ sites using Bio‐Oss®. Smoking is a major risk indicator for peri‐implantitis, whereas the association between history of periodontitis and the risk of peri‐implantitis, based on this specific, well‐maintained cohort and the specific implants used, remains inconclusive.

Effects of implant surface mechanical instrumentation methods on peri-implantitis: An in vitro study using a circumferential bone defect model

Background/purpose

Although several mechanical and chemical debridement techniques have been reported for the management of peri-implantitis, there is no consensus on the most effective method at present. This in vitro study aimed to examine the effects of different mechanical instrumentation techniques on the debridement of hard calcified materials, which are present on the implant surface, as well as the effect of the defect morphology.

Materials and methods

From a total of 15 implants, five each were assigned to one of three decontamination groups (Rotary titanium brush [Ti], tricalcium phosphate air powder abrasive treatment [Air], and titanium ultrasonic scaler [US] groups); the exposed hydroxyapatite (HA)-coated portion was divided into three 1-mm sections (coronal, middle, and apical). The residual-HA of each portion was measured using a digital microscope.

Results

The overall percentage of residual HA coating was significantly lower in the US group than in the Ti or Air groups (p < 0.01). The percentage of residual HA in the coronal portion was significantly lower in the Ti and US groups than in the Air group (p < 0.05 and p < 0.01, respectively). The percentage of residual HA in the middle portion was significantly lower in the US group than in the Air group (p < 0.01). The percentage of residual HA in the apical portion was significantly lower in the Ti group than in the Air or US groups (p < 0.01).

Conclusion

Ti and US were more effective for shallow defects, whereas US was more effective for deeper defects.

Repeated Home-Applied Dual-Light Antibacterial Photodynamic Therapy Can Reduce Plaque Burden, Inflammation, and aMMP-8 in Peri-Implant Disease—A Pilot Study

Until now, in clinical dentistry, antibacterial photodynamic therapy (aPDT) has been restricted to in-office treatments, which hampers repeated applications. This pilot study tested the benefit of a commercially available Lumoral^® device designed for regular periodontal dual-light aPDT treatment at home. Seven patients with peri-implant disease applied dual-light aPDT daily in addition to their normal dental hygiene for four weeks. A single Lumoral^® treatment includes an indocyanine green mouth rinse followed by 40 J/cm² radiant exposure to a combination of 810 nm and 405 nm light. A point-of-care analysis of active-matrix metalloproteinase (aMMP-8), visible plaque index (VPI), bleeding on probing (BOP), and peri-implant pocket depth (PPD) measurements was performed on day 0, day 15, and day 30. Reductions in aMMP-8 (p = 0.047), VPI (p = 0.03), and BOP (p = 0.03) were observed, and PPD was measured as being 1 mm lower in the implant (p = ns). These results suggest a benefit of regular application of dual-light aPDT in peri-implantitis. Frequently repeated application can be a promising approach to diminishing the microbial burden and to lowering the tissue destructive proteolytic and inflammatory load around dental implants. Further studies in larger populations are warranted to show the long-term benefits.

Retrospective Evaluation of Implants Placed in Iliac Crest Autografts and Pristine Bone

Objective: Iliac crest autografts can compensate for severe mandibular atrophy before implant placement. However, the implant success in the augmented bone is not entirely predictable. Here we performed a retrospective cohort study to determine the success and related parameters of implants placed in augmented bone and pristine bone for up to 11 years. Material and Methods: We analyzed 18 patients where 72 implants were placed six months after iliac crest transplantation and 19 patients where 76 implants were placed in pristine bone. The primary endpoint was implant loss. Secondary endpoints were the implant success, peri-implant bone loss, and the clinical parameters related to peri-implantitis. Moreover, we evaluated the oral-health-related quality of life (OHIP). Results: Within a mean follow-up of 5.8 ± 2.2 and 7.6 ± 2.8 years, six but no implants were lost when placed in augmented and pristine bone, respectively. Among those implants remaining in situ, 58% and 68% were rated as implant success (p = 0.09). A total of 11% and 16% of the implants placed in the augmented and the pristine bone were identified as peri-implantitis (p = 0.08). Bone loss was similar in both groups, with a mean of 2.95 ± 1.72 mm and 2.44 ± 0.76 mm. The mean OHIP scores were 16.36 ± 13.76 and 8.78 ± 7.21 in the augmentation and the control group, respectively (p = 0.35). Conclusions: Implants placed in iliac crest autografts have a higher risk for implant loss and lower implant success rates compared to those placed in the pristine bone.

Cross-kingdom microbial interactions in dental implant-related infections: is Candida albicans a new villain?

Candida albicans, an oral fungal opportunistic pathogen, has shown the ability to colonize implant surfaces and has been frequently isolated from biofilms associated with dental implant-related infections, possibly due to its synergistic interactions with certain oral bacteria. Moreover, evidence suggests that this cross-kingdom interaction on implant can encourage bacterial growth, leading to increased fungal virulence and mucosal damage. However, the role of Candida in implant-related infections has been overlooked and not widely explored or even considered by most microbiological analyses and therapeutic approaches. Thus, we summarized the scientific evidence regarding the ability of C. albicans to colonize implant surfaces, interact in implant-related polymicrobial biofilms, and its possible role in peri-implant infections as far as biologic plausibility. Next, a systematic review of preclinical and clinical studies was conducted to identify the relevance and the gap in the existing literature regarding the role of C. albicans in the pathogenesis of peri-implant infections.

Corrosion Behavior of Titanium Dental Implants with Implantoplasty

The procedure generally used to remove bacterial biofilm adhering to the surface of titanium on dental implants is implantoplasty. This treatment is based on the machining of the titanium surface to remove bacterial plaque. In this study, we used 60 grade 4 titanium implants and performed the implantoplasty protocol. Using X-ray diffraction, we determined the stresses accumulated in each of the as-received, machined and debris implants. The resistance to corrosion in open circuit and potentiodynamically in physiological medium has been determined, and the corrosion potentials and intensities have been determined. Tests have been carried out to determine ion release by ICP-MS at different immersion times. The results show that the corrosion resistance and the release of titanium ions into the medium are related to the accumulated energy or the degree of deformation. The titanium debris exhibit compressive residual stresses of −202 MPa, the implant treated with implantoplasty −120 MPa, and as-received −77 MPa, with their corrosion behavior resulting in corrosion rates of 0.501, 0.77, and 0.444 mm/year, respectively. Debris is the material with the worst corrosion resistance and the one that releases the most titanium ions to the physiological medium (15.3 ppb after 21 days vs. 7 ppb for as-received samples). Pitting has been observed on the surface of the debris released into the physiological environment. This behavior should be taken into account by clinicians for the good long-term behavior of implants with implantoplasty.

Implantoplasty Improves Clinical Parameters over a 2-Year Follow-Up: A Case Series

Background and Objectives: Peri-implantitis treatment is still undefined. Regenerative treatment is expensive and technically demanding due to the need to handle biomaterials, membranes and different methodologies of decontamination. Resective treatment and implantoplasty might be a viable solution. This case series presents a 24 month retrospective observational study of 10 peri-implantitis patients treated with implantoplasty. Materials and Methods: In the present case series, 10 peri-implantitis patients (20 implants) were treated with a resective approach and implantoplasty. Previous to implantoplasty, all patients underwent non-surgical treatment. This surgery consisted in a full-thickness flap and implant surface exposure. The exposed non-osseointegrated implant body was submitted to implantoplasty. The flap was apically repositioned and sutured. Patients were accompanied for 24 months. Results: The mean initial probing depth (PD) (PD = 5.37 ± 0.86 mm), bleeding on probing (BoP = 0.12 ± 0.06%) and suppuration (Sup = 0.01 ± 0.01%) decreased significantly at the 12 month evaluation (PD = 2.90 ± 0.39 mm; BoP = 0.01 ± 0.01% and Sup = 0.00 ± 0.00%). Between the 12 and 24 month evaluations, there were no significant clinical changes (PD = 2.85 ± 0.45 mm; BoP = 0.01 ± 0.01% and Sup = 0.00 ± 0.00%). Mucosal recession (MR) had a significant increase between the baseline and the first 12 months (0.69 ± 0.99 mm vs. 1.96 ± 1.33 mm), but there were no significant changes between the 12th and 24th month (1.94 ± 1.48 mm). The success rate was 100% without implant fracture or loss. Conclusions: Resective surgery and implantoplasty might be a valid option in some specific peri-implantitis cases. Properly designed clinical trials are needed to confirm this possibility.

Citric Acid in the Passivation of Titanium Dental Implants: Corrosion Resistance and Bactericide Behavior

The passivation of titanium dental implants is performed in order to clean the surface and obtain a thin layer of protective oxide (TiO2) on the surface of the material in order to improve its behavior against corrosion and prevent the release of ions into the physiological environment. The most common chemical agent for the passivation process is hydrochloric acid (HCl), and in this work we intend to determine the capacity of citric acid as a passivating and bactericidal agent. Discs of commercially pure titanium (c.p.Ti) grade 4 were used with different treatments: control (Ctr), passivated by HCl, passivated by citric acid at 20% at different immersion times (20, 30, and 40 min) and a higher concentration of citric acid (40%) for 20 min. Physical-chemical characterization of all of the treated surfaces has been carried out by scanning electronic microscopy (SEM), confocal microscopy, and the 'Sessile Drop' technique in order to obtain information about different parameters (topography, elemental composition, roughness, wettability, and surface energy) that are relevant to understand the biological response of the material. In order to evaluate the corrosion behavior of the different treatments under physiological conditions, open circuit potential and potentiodynamic tests have been carried out. Additionally, ion release tests were realized by means of ICP-MS. The antibacterial behavior has been evaluated by performing bacterial adhesion tests, in which two strains have been used: Pseudomonas aeruginosa (Gram-) and Streptococcus sanguinis (Gram+). After the adhesion test, a bacterial viability study has been carried out ('Life and Death') and the number of colony-forming units has been calculated with SEM images. The results obtained show that the passivation with citric acid improves the hydrophilic character, corrosion resistance, and presents a bactericide character in comparison with the HCl treatment. The increasing of citric acid concentration improves the bactericide effect but decreases the corrosion resistance parameters. Ion release levels at high citric acid concentrations increase very significantly. The effect of the immersion times studied do not present an effect on the properties.

Long-term outcomes after peri-implantitis treatment and their influencing factors: a retrospective study

Purpose

This study aimed to determine the long-term outcomes after peri-implantitis treatment and the factors affecting these outcomes.

Methods

This study included 92 implants in 45 patients who had been treated for peri-implantitis. Clinical data on the characteristics of patients and their implants were collected retrospectively. The change in the marginal bone level was calculated by comparing the baseline and the most recently obtained (≥3 years after treatment) radiographs. The primary outcome variable was progression of the disease after the treatment at the implant level, which was defined as further bone loss of >1.0 mm or implant removal. A 2-level binary logistic regression analysis was used to identify the effects of possible factors on the primary outcome.

Results

The mean age of the patients was 58.7 years (range, 22–79 years). Progression of peri-implantitis was observed in 64.4% of patients and 63.0% of implants during an observation period of 6.4±2.7 years (mean±standard deviation). Multivariable regression analysis revealed that full compliance to recall visits (P=0.019), smoking (P=0.023), placement of 4 or more implants (P=0.022), and marginal bone loss ≥4 mm at baseline (P=0.027) significantly influenced the treatment outcome.

Conclusions

The long-term results of peri-implantitis treatment can be improved by full compliance on the part of patients, whereas it is impaired by smoking, placement of multiple implants, and severe bone loss at baseline. Encouraging patients to stop smoking and to receive supportive care is recommended before treatment.

Radiographic peri-implant bone loss after a function time up to 15 years

OBJECTIVE

The aim was to assess the degree of radiographic peri-implant bone loss over a follow-up period up to 15 years. In addition, another aim was to identify risk indicators for peri-implant bone loss and for moderate-severe peri-implantitis at patient- and implant level.

MATERIALS AND METHODS

This is a cross-sectional clinical and radiological study of 147 patients with a total of 425 implants in combination with data collected retrospectively for baseline variables. To calculate the peri-implant bone loss (primary outcome variable), the radiographic bone level measurements from baseline were compared to the radiographic bone level measurements at the final radiographic measurement. Multilevel analyses were adopted with peri-implant bone loss and peri-implantitis as outcome variables.

RESULTS

The mean follow-up time was 12.5 years (range 10-15) and the mean age of the patients was 63 years (range 29-83). The mean peri-implant bone loss was 0.94 mm (S.D. 1.3). The prevalence of moderate-severe peri-implantitis at patient level was 17% and 8.9% at implant level. The peri-implant bone loss was significantly more pronounced in healthy implants if moderate-severe peri-implantitis was present in at least one implant within the same patient. The presence of moderate-severe peri-implantitis was significantly associated with general periodontitis Stages III or IV at follow-up and smoking.

CONCLUSION

The presence of moderate-severe peri-implantitis at patient level was found to be a risk indicator of peri-implant bone loss in healthy implants, while smoking and general periodontitis Stages III and IV were risk indicators of moderate-severe peri-implantitis.

Association between Interleukin-1 Polymorphisms and Susceptibility to Dental Peri-Implant Disease: A Meta-Analysis

Background and objective: Interleukins (ILs), as important biochemical mediators, control the host response to inflammation and are associated with bone resorption. In the present meta-analysis, we investigated the association between IL−1 polymorphisms and susceptibility to dental peri-implant disease (PID). Materials and methods: We searched Web of Science, Cochrane Library, Scopus, and PubMed/Medline databases for studies published until 9 September2021, without any restrictions. We calculated the crude OR and 95% confidence intervals (CI) to estimate the associations between IL−1 polymorphisms and PID risk in the five genetic models. We further performed the subgroup analysis, sensitivity analysis, meta-regression, trial sequential analysis, and calculated the publication bias. Results: Out of 212 retrieved records, sixteen articles were used in the meta-analysis. There was no association between IL−1A (–889), IL−1B (−511), IL−1B (+3953), and IL−1RN (VNTR) polymorphisms and the risk of dental PIDs, but there was an increased risk of IL−1B (+3954) in the patients with PIDs. In addition, an association of the composite genotype of IL−1A (−889)/IL−1B (+3953) was observed with the risk of PIDs, but not for the composite genotype of IL−1A (−889)/IL−1B (+3954). The publication year, the ethnicity, sample size, and the outcome were significantly influenced pooled estimates of some genetic models. Trial sequential analysis showed the lack of sufficient sample sizes in the studies. Conclusions: Among IL−1 polymorphisms evaluated in the meta-analysis, the composite genotype of IL−1A (−889)/IL−1B (+3953) and IL−1B (+3954) were the only polymorphisms associated with the risk of PID. The T allele and CT genotype of IL−1B (+3954) polymorphism were also associated with an elevated risk of PID.

One-year outcomes of dental implants with a hybrid surface macro-design placed in patients with history of periodontitis: A randomized clinical trial

AIM

To evaluate the radiological, clinical, and microbiological outcomes of implants with a hybrid surface macro-design in patients with a history of periodontitis.

MATERIAL AND METHODS

The study was designed as a 12-month, parallel-arm, randomized controlled trial where patients with a history of treated periodontitis in need of dental implants for single-unit or short-span prosthesis were randomly allocated to a test [implants with a machined titanium surface in the coronal collar (hybrid; HS)] or a control group [conventional implants with moderately rough surface up to the implant shoulder (RS)]. Patients were followed at 3, 6, and 12 months after loading with assessment of radiological, clinical, and microbiological outcomes, as well as patient-related outcome measures (PROMs).

RESULTS

Forty patients were randomly assigned to either the RS group (n = 20) or the HS (n = 20) group. At 1 year, the mean marginal bone level changes were 0.22 [standard deviation (SD) 0.36] mm for the HS group and 0.22 (SD 0.29) mm for the RS group, with no significant differences between them (p = .961). Similarly, no significant differences in clinical, microbiological, or PROMs were observed between groups.

CONCLUSIONS

HS implants demonstrated radiographic, clinical, and microbiological characteristics equal to RS implants in patients with a history of periodontitis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov (identifier NCT05010382).

Correlations between implant success rate and personality types in the older people: A preliminary case control study

Background/ purpose

Older patients inevitably have a higher need for implant treatment, it is unknown how mental changes or psychological aspects affect the outcome of implant treatment. This study evaluated the success rate of implants and the influence of personality traits in the older people. The goal was to provide evidence for predictable implant treatment while taking into account the unique psychological changes of elders.

Materials and methods

Participants were patients who were able to independently visit our hospital between March 2004 and May 2021. Inclusion criteria were patients aged 65 years or older at the time of implant placement with regular follow-up for at least 1 year. The implant success rate was calculated by counting peri-implantitis and implant loss as failures. Multivariate analysis was used to examine the effect of patient personality characteristics on the success rate.

Results

Fifty-six implants were included in 23 patients (12 men, 11 women), with a mean age of 68.5 years (65–76) and mean maintenance duration of 9 years and 2 months. The cumulative survival rate was 87% at the patient level (94.6% at the implant level). Statistically significant differences were found for adaptive traits (odds ratio [OR] = 0.04) and non-adaptive traits (OR = 6.38); however, no significant differences were found for the other independent variables.

Conclusion

The overall implant success rate was 69.6% at the patient level (82.1% at the implant level). The personality traits in older people had a significant effect on the implant failure rate.

Microbiome differences in periodontal, peri-implant, and healthy sites: a cross-sectional pilot study

OBJECTIVES

To explore microbial communities associated with health and disease status around teeth and dental implants.

MATERIALS AND METHODS

A total of 10 healthy, 24 periodontitis, and 24 peri-implant sites from 24 patients were sequenced by next-generation sequencing. Microbial DNA was extracted and 16S rRNA gene was amplified. Bioinformatic analyses were performed using quantitative insights into microbial ecology (QIIME), linear discriminant analysis effect size (LEfSE), and STAMP.

RESULTS

Differences in microbial diversity across three types of sites were not statistically significant. Several genera and species were more prevalent in healthy compared with diseased sites, including Lautropia, Rothia and Capnocytophaga and Kingella. Among diseased sites, Peptostreptococcaceae, Dialister, Mongibacterium, Atopobium, and Filifactor were over-represented in peri-implantitis sites, while Bacteroidales was more abundant in periodontitis sites.

CONCLUSIONS

Diseased periodontal and peri-implant sites and corresponding healthy sites have distinct microbiological profiles. These findings suggest that microbial analyses could identify biomarkers for periodontal health and disease and lead to the development of new strategies to improve periodontal health and treat peri-implant and periodontal diseases.

CLINICAL RELEVANCE

The study contributes to improving our understanding of healthy, periodontally affected, and peri-implantitis sites which can improve our ability to diagnose, monitor, and manage these oral conditions.

Baseline selection for evaluation of peri-implant soft tissue changes: a clinical trial

Background

To select the optimal baseline for evaluation of peri-implant soft tissue changes among 1, 2, and 3 weeks after definitive crown insertion.

Methods

A total of 22 individuals who required implant restoration were recruited to this study. Each participant received a screw-retained conventional implant restoration. Peri-implant soft tissue was captured by an intraoral scanner and analyzed by 3D analysis software. Soft tissue changes [mucosal margin (MM) and soft tissue thickness (STT)] on the buccal side of implant sites were evaluated at 1, 2, and 3 weeks after definitive crown insertion. One-way analysis of variance (ANOVA) for repeated measurement and Tukey’s test were used to analyze significant differences between the 3 time points (α=0.05).

Results

An increased volume of peri-implant soft tissue was observed shortly after definitive crown insertion. Based on the findings of peri-implant soft tissue changes, significant differences were observed between weeks 1 and 2 (P<0.01), and weeks 1 and 3 (P<0.01), while there was no significant difference between weeks 2 and 3 (P>0.05).

Conclusions

Minimal peri-implant soft tissue changes occurred in this study. The time point of 2 weeks after definitive crown insertion was preliminarily selected as the baseline. The small sample size and few time points must be taken into consideration when interpreting these findings.

Trial Registration

This study was retrospectively registered in the Chinese Clinical Trial Registry (Registration number: ChiCTR2000037954; Date of registration: 6 September 2020).

Microbial profiles of peri-implant mucositis and peri-implantitis: Submucosal microbial dysbiosis correlates with disease severity

OBJECTIVE

To investigate the microbiome characteristics of peri-implant mucositis (PM) and peri-implantitis (PI), and to analyse the correlation between disease severity and submucosal microbial dysbiosis.

MATERIALS AND METHODS

A cross-sectional study design was conducted. Submucosal biofilm samples from 27 PM sites and 37 PI sites from 64 patients were collected and analysed using 16S rRNA gene sequencing (Illumina). Differences in microbiological profiles between PM and PI were evaluated using the α-diversity, β-diversity and linear discriminant analysis effect size (LEfSe) analysis. The relative abundances of the taxa at the phylum and genus levels were compared using the Wilcoxon rank test and logistic regression. The microbial dysbiosis index (MDI) was calculated, and its relationship with clinical measurements (probing depth, bleeding on probing and marginal bone loss, among others) was analysed using Pearson's correlation coefficient.

RESULTS

The overall microbiome distribution in the PM and PI sites was similar according to α- and β-diversity. Twenty-three taxa at the genus level and two taxa at the phylum level showed significant differences in relative abundance between the two clinical classifications. Five taxa at the genus level were screened out for the MDI calculation after logistic regression. No clinical measurements but marginal bone loss showed a significant positive correlation with microbial dysbiosis.

CONCLUSION

The microbiome richness, diversity and distribution were similar in PM and PI sites, including both common periodontal bacteria and novel species. In addition, an increase in marginal bone loss was significantly associated with submucosal microbial dysbiosis.

Evaluating the Knowledge of General Dentist Towards the Management of Peri-Implant Diseases: A Multi-Center, Cross-Sectional Study

Background:

Recently, implants have been widely considered as an option for replacing missing teeth. There are several biological conditions that must be considered for the success of an implant. Failure to satisfy any of these factors may result in complications, such as peri-implantitis or failure of the implant.

Aim:

The aim of this study was to evaluate the general dentist's attitude towards the management of peri-implant diseases in Saudi Arabia.

Methods:

A multicenter cross-sectional electronic-based questionnaire was formulated based on the validated questionnaire from a previous study. It was targeted towards the general dental practitioners in Saudi Arabia. The study sample consisted of 721 general dental practitioners. The questionnaire consisted of 17 questions divided into five sections. Pearson's chi-square test was used for inferential statistical analysis with Holm's correction, for adjusted p-value, the alpha at 95% confidence interval was 0.05, and all values below alpha were considered statistically significant.

Results:

The majority of participants had attended an implant training course (51.2%) while the rest had not (48.7%). The majority of the participants (67.3%) thought they need special instruments for the detection of peri-implantitis but only 29.5% thought they do not need any special instruments for the intended purpose. Most participants (79.3%) said they can identify and differentiate between normal and abnormal soft tissue around an implant, while 6.5% of the respondents could not. More than half of the participants (54.8%) could differentiate between peri-implant mucositis and peri-implantitis, and 19.4% had no idea about this. Amoxicillin & metronidazole was considered as the best and most effective antibiotic by the majority of respondents (76%), while only (5%) of dentists selected ciprofloxacin.

Conclusion:

This study concludes by suggesting that most of the participants have adequate knowledge about peri-implant soft tissue assessment, mechanism of periodontitis and peri-implantitis, its initiation and progression along with its management. Most of the participants found the training courses on peri-implantitis to be efficient. It is recommended to conduct more courses and studies that would aim at understanding the pathogenesis, etiology, diagnosis, and treatment of peri-implant diseases so as to increase awareness among general dentists.

Peri-Implant Diseases

Osseointegrated dental implants have become an increasingly popular modality of treatment for the replacement of absent or lost teeth because of its high rates of long-term survival when used to support various types of dental prostheses. However, complications and implant failure can still occur and are considered by many clinicians as a major obstacle for implant treatment. Biological complications mainly refer to inflammatory conditions of the soft tissues and bone surrounding implants and their restorative components, which are induced by the accumulation of bacterial biofilm. Two clinical varieties may be distinguished: peri-implant mucositis and peri-implantitis. Peri-implant mucositis is a reversible, plaque-induced inflammatory lesion confined to the peri-implant soft tissue unit, whereas peri-implantitis is an extension of peri-implant mucositis to involve the bone supporting the implant. Diagnosing and managing these biological complications is of utmost importance for the implant surgeon and dental practitioner. This review encompasses the etiology, diagnostic aspects, prevention, and management of biological complications.

Efficacy of an Er:YAG laser in the decontamination of dental implant surfaces: An in vitro study

BACKGROUND

Emergence of peri-implant diseases led to the development of various methods for implant surface decontamination. This study was designed to compare the efficacy of biofilm removal from implant-like titanium surfaces by an erbium-doped yttrium-aluminum-garnet (Er:YAG) laser, titanium brush, and carbon fiber curet.

METHODS

Eight study subjects were recruited. A custom mouth appliance that held eight sandblasted and acid-etched titanium discs was fabricated for each subject. Subjects were asked to wear this appliance for 72 hours to allow for biofilm development. After retrieval, discs were removed and randomized to one of four treatment groups. The discs were stained with a two-component nucleic acid dye kit, and the residual biofilm was visualized under fluorescence microscopy. Quantification of residual biofilm was performed using an image analysis software and expressed as the percentage surface area.

RESULTS

Fifty-nine titanium discs were randomized to the four treatment groups. The percentage of titanium disc area covered by residual biofilm was 74.0% ± 21.6%, 32.8% ± 24.0%, 11.8% ± 10.3%, and 20.1% ± 19.2% in the control, Er:YAG, titanium brush and carbon fiber curet groups, respectively (mean ± SD). The biofilm-covered area significantly decreased in each of the three treatment groups compared with control (P < 0.008). Comparisons between treatment groups did not reveal statistical significance.

CONCLUSIONS

Er:YAG laser treatment is an effective method for reducing the bacterial biofilm on titanium discs. However, on a threadless titanium surface, Er:YAG laser does not exhibit a significantly greater efficacy in biofilm removal than commonly used titanium brushes or carbon fiber curets.

Adjunctive benefits of systemic metronidazole on non-surgical treatment of peri-implantitis. A randomized placebo-controlled clinical trial

AIM

To study clinical, radiographic, and microbiological outcomes after non-surgical therapy of peri-implantitis with or without adjunctive systemic metronidazole.

MATERIALS AND METHODS

A randomized placebo-controlled clinical trial was carried out in 32 subjects (62 implants) diagnosed with peri-implantitis. Implants received a mechanical non-surgical debridement session and systemic metronidazole or placebo. Clinical, radiographic, and microbiological outcomes were evaluated at baseline, 3, 6, and 12 months.

RESULTS

After 12 months, the test treatment resulted in significantly greater PPD reduction (2.53 vs. 1.02 mm) and CAL gain (2.14 vs. 0.53 mm) (p value <.05) in comparison with placebo. The test treatment also resulted in additional radiographic bone gain (2.33 vs. 1.13 mm) compared with placebo (p value <.05). There was a significantly greater decrease in Porphyromonas gingivalis, Tannerella forsythia, and Campylobacter rectus counts compared with the control group (p value <.05). At the end of follow-up, 56.3% of patients met the success criteria in the test group and 25% in the control group.

CONCLUSIONS

The use of systemic metronidazole as an adjunct to non-surgical treatment of peri-implantitis resulted in significant additional improvements in clinical, radiographic, and microbiological parameters after 12 months of follow-up. This study is registered in ClinicalTrials.gov (NCT03564301).

Local/Topical Antibiotics for Peri-Implantitis Treatment: A Systematic Review

Most studies indicate that the mechanical removal of the bacterial biofilm from the implant surface is the central goal of peri-implantitis therapy. However, controversial results in the treatment of peri-implantitis have led to the consideration of additional strategies that include surgical approaches and chemical adjuvants. Local/topical antibiotics, such as minocycline, azithromycin, tetracycline, amoxicillin, doxycycline, and metronidazole, may improve the efficacy of the definitive treatment of the disease, but the lack of conclusive findings prevents their use in clinical practice. This systematic review aimed to evaluate the effect of local/topical antibiotics for peri-implantitis treatment. Randomised controlled studies (RCT) on patients with peri-implantitis and comparing the efficacy of local/topical antibiotics vs. placebo or mechanical debridement were included. A systematic search strategy was carried out using three registered databases (PubMed, Web of Science, and Scopus). RoB2 was used to assess risk of bias. Five RCTs were identified (n = 250 patients and 333 implants). Contrast results emerged among the included studies, and a high heterogeneity level was observed. Risk of bias revealed some concerns for three studies out of five, while one study was judged at high risk. Only one study analysed the limitations of its findings. Overall, local antibiotic use can be considered a valid approach in the treatment of peri-implantitis. Therefore, future long-term clinical trials with standardised protocols and antibiotics with similar biological activity profiles should be tested to achieve a valid and definitive conclusion.

Diagnosis of inflammatory peri-implant diseases using an immunochromatographic assay for calprotectin in peri-implant crevicular fluid

Background

The incidence rate of peri-implant diseases is increasing with implant placement. Early detection of peri-implant diseases is important to prevent and treat these diseases, and a simple and objective diagnostic method is expected. Immunochromatographic (IC) assays are used for rapid diagnostic methods for some diseases. The aim of this clinical study was to determine the amount of calprotectin, an inflammatory marker, in peri-implant crevicular fluid (PICF) using an IC chip, and estimate the possibility of this diagnostic system.

Methods

Forty-six individuals with dental implants participated in a pilot study. PICF samples were collected from the peri-implant sites with or without inflammation after clinical examinations including probing depth (PD), bleeding on probing (BOP) and gingival index (GI). Calprotectin in PICF was determined by an IC chip and enzyme-linked immunosorbent assay (ELISA) for calprotectin. The density of calprotectin line on the IC chip was measured using an IC reader (IC reader value). The relationship between IC reader value and ELISA value or clinical parameters was investigated. A receiver operating characteristic (ROC) curve analysis of IC reader value of calprotectin was performed to predict inflammation in peri-implant diseases.

Results

IC reader value of calprotectin was significantly correlated with its ELISA value and PD. IC reader values of calprotectin in PICF samples from periodontal sites with GI-1 and GI-2, and with BOP-positive sites were significantly higher than those of PICF samples from GI-0 sites, and BOP-negative sites, respectively. The IC reader value for calprotectin in PICF samples from inflammatory diseased sites was significantly higher than that of non-diseased sites. ROC analysis suggested that the IC reader value of PICF calprotectin was useful for predicting inflammatory peri-implant diseases.

Conclusion

IC assay for PICF calprotectin may be a possible system for diagnosing the inflammatory peri-implant diseases.

Intra- and Inter-Examiner Repeatability of Diagnostic Peri-implant Clinical Measurement: A Pilot Study

Despite the crucial role of examiner reliability on quality research and practice, there is still limited literature analyzing factors affecting examiner variability of peri-implant clinical measurements. The present study investigated clinical peri-implant parameters to quantify their repeatability and investigate factors that may affect their accuracy. Thirty-three implants were examined by four operators. Peri-implant probing depth (PD), recession (REC) and gingival index (GI) were measured for agreement and included for analysis. Agreement was quantified using intraclass correlation coefficients (ICC; 95% CI); mixed linear and logistic regressions were used to assess additional variables. The overall inter-examiner agreement was comparable between PD (0.80) and REC (0.78), but significantly worse for GI (0.45) (p<0.001). Similarly, the intra-examiner agreement was similar for PD (0.81) and REC (0.80), but significantly worse for GI (0.57) (p<0.05). The magnitude of PD did not influence agreement. In contrast, increasing disagreement was noted for positive REC (OR: 3.0), negative REC (OR: 4.8) and lower GI (OR: 4.4). The incidence of bleeding on probing and severity of GI increased for deeper PD (0.113 unit increase per mm). Negative and positive values of recession and lower GI were associated with increasing disagreement. Radiographic bone loss, restoration contour and implant diameter did not impact PD accuracy within this study. In conclusion, within the limitations of the study, GI measurements presented higher variability than PD and REC. PD and GI were associated with one another and increased after multiple measurements.

Potential of Carbon-Based Nanocomposites for Dental Tissue Engineering and Regeneration

While conventional dental implants focus on mechanical properties, recent advances in functional carbon nanomaterials (CNMs) accelerated the facilitation of functionalities including osteoinduction, osteoconduction, and osseointegration. The surface functionalization with CNMs in dental implants has emerged as a novel strategy for reinforcement and as a bioactive cue due to their potential for mechanical reinforcing, osseointegration, and antimicrobial properties. Numerous developments in the fabrication and biological studies of CNMs have provided various opportunities to expand their application to dental regeneration and restoration. In this review, we discuss the advances in novel dental implants with CNMs in terms of tissue engineering, including material combination, coating strategies, and biofunctionalities. We present a brief overview of recent findings and progression in the research to show the promising aspect of CNMs for dental implant application. In conclusion, it is shown that further development of surface functionalization with CNMs may provide innovative results with clinical potential for improved osseointegration after implantation.

Evaluation of the implant disease risk assessment (IDRA) tool: A retrospective study in patients with treated periodontitis and implant-supported fixed dental prostheses (FDPs)

Aim

To evaluate the Implant Disease Risk Assessment (IDRA) tool for the prediction of peri‐implantitis in treated periodontitis patients with implant‐supported fixed dental prostheses (FDPs) after at least 5 years of function.

Material and methods

From the patient pool of implant patients enrolled in a regular supportive periodontal therapy programme (SPT) for at least 5 years, 239 patients were screened. Eighty patients met the inclusion criteria and underwent evaluation through the criteria of the IDRA tool. Areas under the curve (AUCs) for receiver operating characteristic (ROC) curves including 95% confidence intervals were estimated.

Results

Seventy‐nine patients (43 males and 36 females, 8 smokers), aged on average 59.0 years (range: 40–79 years) at baseline (i.e. FDP delivery) were analysed. The calculated IDRA‐risk was in 34 patients (42.5%) a moderate risk, while 45 patients (56.3%) were considered at high IDRA‐risk. One patient categorized at low IDRA‐risk was excluded from the analysis.

The AUC was 0.613 (95% CI: 0.464–0.762) if the IDRA‐risk was associated with prevalence of peri‐implantitis at the most recent follow‐up. Peri‐implantitis was diagnosed in 4 patients (12%) at moderate and in 12 patients (27%) at high IDRA‐risk, respectively. The calculated odds ratio for developing peri‐implantitis in patients with high IDRA‐risk compared with patients with moderate IDRA‐risk was 2.727 with no statistically significant difference between the two groups (95% CI: 0.793–9.376).

Conclusion

Within the limitations of the present retrospective study, the IDRA algorithm might represent a promising tool to assess patients at moderate or high risk of developing peri‐implantitis.

Osseointegrated implant survival, success and prosthodontic outcomes in composite free flaps: A 10-year retrospective cohort study

OBJECTIVES

To evaluate implant survival, success and prosthodontic outcomes in a variety of composite free flaps.

MATERIAL AND METHODS

A retrospective analysis of patient records was used for data collection of implants placed into flaps. Free flap donor sites included fibula, iliac crest, scapula, medial femoral condyle and radial forearm. Kaplan-Meier survival curves were used to estimate survival. Cox regression was used to assess variables affecting survival, and binary logistic regression was utilised to determine effect of variables on prosthodontic outcomes.

RESULTS

There were 150 implants placed into 45 fibula, 98 implants into 29 iliac crest, 62 implants into 22 scapula, 6 implants into 3 medial femoral condyle and 2 implants in radial forearm composite free flaps. There was no difference in survival or success between or within the various flaps. Active smoking, increasing age, male gender and radiotherapy were associated with implant failure. Of patients completing prosthodontic rehabilitation, 93% were successful. There was no difference in likelihood of failure between different flap types. Fixed implant-supported dentures were associated with poor oral hygiene compared with removable designs (OR2.9, 95%CI 1.1-7.8, p = .03).

CONCLUSIONS

There is adequate survival and success of implants in common flaps. Caution is required when planning implants in patients exposed to radiotherapy and smokers. Ability to maintain adequate oral hygiene is an important prosthetic design consideration.

Diagnostic potential and future directions of matrix metalloproteinases as biomarkers in gingival crevicular fluid of oral and systemic diseases

Gingival crevicular fluid (GCF) is a physiological fluid and an inflammatory serum exudate derived from the gingival plexus of blood vessels and mixed with host tissues and subgingival plaque flows. In addition to proteins, GCF contains a diverse population of cells, including desquamated epithelial cells, cytokines, electrolytes, and bacteria from adjacent plaques. Recently, matrix metalloproteinases(MMPs), which are endopeptidases that are active against extracellular macromolecules, in GCF have been revealed as potential utility biomarkers for the diagnosis and follow-up of oral and systemic diseases, thereby facilitating the early evaluation of malignancy risk and the monitoring of disease progression and treatment response. Tissue inhibitors of metalloproteinases (TIMPs) are specific inhibitors of matrixins that participate in the regulation of local activities of MMPs in tissues. This review provides an overview of the latest findings on the diagnostic and prognostic values of MMPs and TIMPs in GCF of oral and systemic diseases, including periodontal disease, pulpitis, peri-implantitis and cardiovascular disease as well as the extraction, detection and analytical methods for GCF.

Comparison of RANKL and OPG levels in peri-implant crevicular fluid between healthy and diseased peri-implant tissues. A systematic review and meta-analysis

OBJECTIVES

To assess RANKL and OPG levels, as well as RANKL/OPG ratio, in peri-implant crevicular fluid (PICF), in dental implants presenting peri-implantitis (PI) in comparison to healthy implants (H) and to implants with peri-implant mucositis (MU).

MATERIALS AND METHODS

An electronic search based on the PICO framework, supplemented by hand searching, was conducted in MEDLINE and EMBASE, using the Ovid interface from 1996 up to and including the 17^th of December 2019 in order to identify relevant clinical studies. A combination of MeSH terms and text words was utilized for this purpose. Sequential screenings at the title, abstract, and full-text levels were performed independently and in duplicate. A random-effects meta-analysis was conducted and mean value standardized differences, between PI and H groups, were utilized as effect sizes.

RESULTS

Out of 1961 titles, which were revealed by the search strategy, 11 articles fulfilled the inclusion criteria and were incorporated in the systematic review. Meta-analytical processing was performed for RANKL (4 articles), OPG (5 articles), and RANKL/OPG ratio (5 articles) in PI and H groups. The total effect for RANKL mean differences between PI and H groups indicated a tendency but not a statistical significance (P = 0.078) in favor of the PI group, while no statistically significant differences were found for OPG and the ratio levels in the examined groups.

CONCLUSIONS

There is limited evidence that levels of the examined biomarkers, RANKL, and OPG as well as the RANKL/OPG ratio, in PICF, may be considered strong indicators for distinguishing between healthy and inflamed peri-implant sites.

CLINICAL RELEVANCE

Biomarker identification in PICF, which could differentiate between healthy and diseased dental implants, might represent a valuable non-invasive method suitable for implant pathology and implant therapy prognosis.

Prevalence and risk indicators for peri-implant diseases: A literature review

Peri-implant diseases are known as undesirable conditions that can occur after implant therapy. Although several risk indicators are becoming clear, the causes of peri-implant diseases have not been completely investigated. The purpose of this review was to summarize the prevalence and risk indicators for peri-implant diseases by referring to current papers from various angles. Many studies have reported the varied prevalence of peri-implant mucositis (23.9%-88.0% at the patient level and 9.7%-81.0% at the implant level) and peri-implantitis (8.9%-45% at the patient level and 4.8%-23.0% at the implant level). Additionally, several studies concluded that poor oral hygiene and lack of regular maintenance were strongly correlated with the development of both peri-implant mucositis and peri-implantitis. Diabetes and a history of periodontitis were revealed as risk indicators for peri-implantitis. However, there was no definitive conclusion about the correlations between peri-implant diseases and other factors such as smoking, the shape of the implant superstructure, and the condition of the keratinized mucosa. Further studies useful for evidence-based decision-making are needed for predictable implant therapy in the long term.

Predictive modeling for peri-implantitis by using machine learning techniques

The purpose of this retrospective cohort study was to create a model for predicting the onset of peri-implantitis by using machine learning methods and to clarify interactions between risk indicators. This study evaluated 254 implants, 127 with and 127 without peri-implantitis, from among 1408 implants with at least 4 years in function. Demographic data and parameters known to be risk factors for the development of peri-implantitis were analyzed with three models: logistic regression, support vector machines, and random forests (RF). As the results, RF had the highest performance in predicting the onset of peri-implantitis (AUC: 0.71, accuracy: 0.70, precision: 0.72, recall: 0.66, and f1-score: 0.69). The factor that had the most influence on prediction was implant functional time, followed by oral hygiene. In addition, PCR of more than 50% to 60%, smoking more than 3 cigarettes/day, KMW less than 2 mm, and the presence of less than two occlusal supports tended to be associated with an increased risk of peri-implantitis. Moreover, these risk indicators were not independent and had complex effects on each other. The results of this study suggest that peri-implantitis onset was predicted in 70% of cases, by RF which allows consideration of nonlinear relational data with complex interactions.

Chemokine Receptor 2 (CXCR2) Gene Polymorphisms and Their Association with the Risk of Developing Peri-Implantitis in Chinese Han Population

Purpose

This study aimed to investigate the role of chemokine receptor 2 (CXCR2) gene polymorphisms in peri-implantitis susceptibility in a Chinese Han population.

Patients and Methods

A total of 260 individuals were included in this study, including 127 peri-implantitis patients and 133 healthy implants. CXCR2 gene rs2230054 and rs1126580 polymorphisms in different groups were analyzed by the Chi-square test. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were employed to evaluate the association between CXCR2 polymorphism and peri-implantitis susceptibility.

Results

The CT genotype of rs2230054 and the AG genotype and G allele of rs1126580 significantly increased in peri-implantitis patients compared with healthy implants (P < 0.05). The CT genotype of rs2230054 (OR = 1.825, 95% CI = 1.028–3.239) and the AG genotype of rs1126580 (OR = 2.223, 95% CI 1.272–3.885) carriers had a high risk to infect with peri-implantitis. Additionally, these CXCR2 gene polymorphisms have been revealed to be associated with the periodontal status of peri-implantitis patients.

Conclusion

The CXCR2 gene rs2230054 and rs1126580 polymorphisms were associated with the peri-implantitis susceptibility in the Chinese Han population. The CT genotype of rs2230054 and the AG genotype and G allele of rs1126580 serve as risk factors for the occurrence of peri-implantitis.

At which bone level are implants explanted?

OBJECTIVES

Clear guidelines when to remove an implant are missing. The aim of this study was to evaluate the amount of peri-implant bone loss at explantation by specialists.

MATERIAL AND METHODS

Implantology specialists were asked to provide implants explanted due to peri-implantitis with related clinical information. Early failures (survival time <12 months) were analyzed separately. Questionnaires inquired age, sex, smoking, implant location, usage of bone substitutes, and implant brand. Explants were measured and bone loss was assessed using radiographs. Covariate-adjusted mixed-effects models were evaluated for bone loss and survival time.

RESULTS

Twelve dental offices provided 192 explants from 161 patients with 99 related radiographs. Thirty-three (17.2%) explants were early failures. Excluding early failures, average survival time was 9.5 ± 5.8 years with absolute and relative bone loss of 7.0 ± 2.7 mm and 66.2 ± 23.7%, respectively. Late failures were removed at mean bone loss of 57.7% in the maxilla and 73.7% in the mandible irrespective of survival time. In fully adjusted mixed-effects models, only age at implantation (B = -0.19; 95% CI: -0.27, -0.10) remained a significant factor for survival time. Implants exhibited significantly more relative bone loss if they were positioned in the mandible (B = 17.3; 95% CI: 3.91, 30.72) or if they were shorter (B = -2.79; 95% CI: -5.50, -0.08).

CONCLUSIONS

Though the mean bone loss (66.2%) at which implants were explanted was in accordance with the literature, its wide variation and differentiation between jaws showed that the profession has no universally accepted threshold beyond which an implant cannot be preserved.

Clinical Evaluation of Crestal Bone Levels, Peri-Implant Indices, and Mucosal Margin Position of Immediately Impressed Posterior Dental Implants: A Cross-Sectional Study

PURPOSE

This is a cross-sectional clinical study to evaluate crestal bone levels, mucosal margin position, probing depths, bleeding on probing, and plaque and bleeding indices of implants restored with an immediate impression workflow compared to implants restored with a delayed impression workflow.

MATERIALS AND METHODS

Patients who had received a posterior single implant crown in the premolar and molar regions were identified and scheduled for a single-visit study appointment. Outcome measurements included soft tissues peri-implant indices, peri-implant mucosal margin position, and crestal bone levels. Several systemic-, local-, and prosthesis-related factors were recorded. Bitewing radiographs were used to assess crestal bone levels. Wilcoxon rank sum test was used to compare the medians of continuous measurements and Pearson chi-square test (or Fisher's exact test) was used to compare the distributions of categorical variables between the two groups.

RESULTS

Twenty eight patients were included. Crestal bone levels, peri-implant mucosal margin position and peri-implant soft tissue parameters for the immediately impressed group were not statistically different from the delayed impressed group, except for probing depth for the immediately impressed buccal site, which was less than that of the delayed group. Mesial bone level for cement-retained crowns was significantly more coronal than for screw-retained ones.

CONCLUSIONS

While an isolated statistical difference was found in probing depth, the current study suggests that there is no clinically significant difference between implants impressed with immediate and delayed implant workflows when considering crestal bone levels, peri-implant mucosal margin position, and most peri-implant indices.

Is bleeding on probing a reliable clinical indicator of peri-implant diseases?

Bleeding on probing (BOP) is regarded as an indispensable diagnostic tool for evaluating periodontal disease activity; however, its role in peri-implant disease is more intricate. Much of the confusion about the interpretation originates from drawing parallels between periodontal and peri-implant conditions. BOP can originate from two forms of probing in implants: traumatic or pathologic induction. This, in addition to the dichotomous scale of BOP can complicate diagnosis. The objective of this commentary is to discuss the following: 1) the value of BOP as a diagnostic tool for peri-implant diseases; 2) the reasons it should be distinct from value for diagnosing periodontal and peri-implant diseases; and 3) the current best evidence on how to implement it in daily clinical practice. A comprehensive bleeding index is proposed for evaluating and monitoring peri-implant conditions. BOP should be used in addition to other parameters such as visual signs of inflammation, probing depth, and progressive bone loss before a peri-implant diagnosis is established.

Influence of Smoking on Dental Implant Osseointegration: A Radiofrequency Analysis of 194 Implants

Although many studies have related smoking to peri-implantitis and marginal bone loss, little is known of its potential impact on dental implant osseointegration. The present clinical study explores the influence of smoking on secondary stabilization based in radiofrequency analysis. A total of 194 implants in 114 patients were included. Implant stability was evaluated on the day of surgery and at a minimum of 90 days after implantation, when osseointegration is considered to have been completed. The evolution of implant stability was compared between 2 groups: smokers and nonsmokers. The following variables were also analyzed: implant brand and model, length, diameter, insertion torque, bone density according to the Misch classification, location of the implant, and patient age and gender. The results showed that smoking did not affect the primary stability of the implant, although it was associated with a marked decrease in secondary stability. The nonsmokers showed a gain of 2.69 points (95% confidence interval [CI]: 1.529-3.865; P < .001) in the osseointegration process. However, in the smokers group, implant stability was seen to decrease 0.91 points (95% CI: -3.424 to 1.600; P < .004), generating a difference of 3.61 points between smokers and nonsmokers. Smoking is thus concluded to be an important factor that must be taken into account when seeking good implant osseointegration outcomes.

Dentists' preferences in implant maintenance and hygiene instruction

BACKGROUND

This study investigated the preferences of dentists in Australia in providing professional implant maintenance and implant-specific oral hygiene instructions (OHI).

METHODS

General dentists were surveyed online about their preferences in peri-implant diagnostics, maintenance provision, armamentarium used, and implant OHI techniques and frequency.

RESULTS

Most of the 303 respondents (96%) provided maintenance services; 87.6% reviewed implants regularly while 10.7% only performed diagnostics after detecting clinical signs/symptoms. Supragingival prosthesis cleaning was performed by 77.9% of respondents, 35.0% performed subgingival debridement, 41.9% treated peri-implant mucositis and 18.2% treated peri-implantitis. About 15% did not treat nor refer peri-implant disease, including significantly more non-implant providers and dentists without implant training. Maintenance armamentarium commonly included floss (76.3%), prophylaxis (73.9%), plastic curettes (43.3%) and stainless-steel ultrasonics (38.0%). Brushing (86.5%), flossing (73.9%) and interdental brush use (68.3%) were most commonly recommended. Implant OHI was repeated routinely by 57.4% of dentists who provided it. Dentists with greater implant training and experience were more likely to perform reviews and complex maintenance procedures.

CONCLUSIONS

Peri-implant diagnostics performed, treatments provided and armamentarium varied among dentists. Implant providers and those with higher levels of training had more preventative approaches to implant OHI. Possible shortcomings in disease management and OHI reinforcement were identified.

Biomarker levels in peri-implant crevicular fluid of healthy implants, untreated and non-surgically treated implants with peri-implantitis

AIM

To compare biomarker levels in peri-implant crevicular fluid (PICF) of healthy implants with levels in PICF of implants with peri-implantitis (before and after non-surgical treatment).

MATERIALS AND METHODS

Samples were taken from 20 healthy implants (n = 17 patients) and from 20 implants with peri-implantitis (n = 19 patients) before and 3 months after non-surgical treatment using the Airflow Master Piezon^® (EMS). A Luminex™ assay was used to evaluate pro-inflammatory and anti-inflammatory cytokines IL-1β, TNF-α, IL-6 and G-CSF, collagen degradation enzyme MMP-8, chemokines MCP-1 & MIP-1α/CCL3, bone markers OPG and sRANKL and interferon-γ. Clinical and radiographical characteristics were assessed. A Mann-Whitney U and Wilcoxon signed-rank test analysed between- and within-group differences.

RESULTS

IL-1β and MMP-8 levels were found significantly elevated in implants with peri-implantitis (p = .007; p = <.001, respectively). No difference in levels of TNF-α, IL-6, MCP-1 and MIP-1α/CCL3, OPG and G-CSF between healthy and diseased implants was found. Levels of sRANKL and INF-γ were under the level of detection. None of the biomarker levels improved after non-surgical therapy, and levels of IL-1β and MMP-8 remained high.

CONCLUSION

Implants diagnosed with peri-implantitis have higher levels of IL-1β and MMP-8 in PICF compared to healthy implants. Non-surgical therapy did not influence the inflammatory immune response.

Crestal bone loss associated with different implant surfaces in the posterior mandible in patients with a history of periodontitis. A retrospective study

OBJECTIVE

To retrospectively assess the interproximal bone loss (CBL) in external hexagon implants (EHI), with different surface micro-topography, placed in the posterior mandible in patients with a history of periodontitis undergoing supportive periodontal care.

MATERIAL AND METHODS

268 consecutive patients received 755 EHI implants in the mandibular molar region between 2007 and 2015 with the following surface characteristics: 72 turned, 145 hybrids (double acid-etched/turned), and 538 anodized. CBL was yearly evaluated by analysing calibrated digital periapical radiographs, with a follow-up of 1-6 years. Data on implant survival were also calculated.

RESULTS

At 6 years (53 patients), the mean CBL was 1.34/1.42 mm at patient/implant level, respectively (range: 0-5.2 mm). Significantly higher CBL was detected in anodized implants than in turned and hybrid implants (1.92/1.46/1.02 mm) (p < .01). The maximum CBL values were found in 2 anodized implants at 4 years (6.3 and 8.1 mm). CBL ≥2 mm was detected in 18% of implants at 3 years and 35% at 6 (p < 2.2 × 10^-16 ), this prevalence being 2.6 times higher in the anodized than in the hybrid and turned group (40%/15.6%, p < .0094). At 6 years, 25 anodized implants presented CBL ≥3 mm (18%). 6 anodized implants (5 patients) were removed between 4 and 5 years.

CONCLUSION

A significant higher CBL was observed in anodized, compared to hybrid and turned implants, when placed in the mandibular molar region of periodontal patients, with a follow-up of 1 to 6 years.

Thermal effects of various drill materials during implant site preparation-Ceramic vs. stainless steel drills: A comparative in vitro study in a standardised bovine bone model

OBJECTIVES

The aim of this study was to evaluate thermal effects of ceramic and metal implant drills during implant site preparation using a standardised bovine model.

MATERIAL AND METHODS

A total of 320 automated intermittent osteotomies of 10- and 16-mm drilling depths were performed using zirconium dioxide-based and stainless steel drills. Various drill diameters (2.0/ 2.2, 2.8, 3.5, 4.2 mm ∅) and different cooling methods (without/ with external saline irrigation) were investigated at room temperature (21 ± 1°C). Temperature changes were recorded in real time using two custom-built multichannel thermoprobes in 1- and 2-mm distance to the osteotomy site. For comparisons, a linear mixed model was estimated.

RESULTS

Comparing thermal effects, significantly lower temperatures could be detected with steel-based drills in various drill diameters, regardless of drilling depth or irrigation method. Recorded temperatures for metal drills of all diameters and drilling depths using external irrigation were below the defined critical temperature threshold of 47°C, whereas ceramic drills of smaller diameters reached or exceeded the harmful temperature threshold at 16-mm drilling depths, regardless of whether irrigation was applied or not. The results of this study suggest that the highest temperature changes were not found at the deepest point of the osteotomy site but were observed at subcortical and deeper layers of bone, depending on drill material, drill diameter, drilling depth and irrigation method.

CONCLUSIONS

This standardised investigation revealed drill material and geometry to have a substantial impact on heat generation, as well as external irrigation, drilling depth and drill diameter.

The occurrence of peri-implant mucositis associated with the shift of submucosal microbiome in patients with a history of periodontitis during the first two years

AIM

To investigate the dynamic changes of peri-implant microbiome in patients with a history of periodontitis and to construct a microbial prediction model.

MATERIALS AND METHODS

The prospective study was performed at one month (T1), one year (T2) and two years (T3) after restoration. Clinical examinations [probing depth (PD), bleeding on probing (BOP), suppuration (SUP)], radiographic examinations and sample collection were conducted at three timepoints. Peri-implant sulcular fluid (PISF) was collected and analysed by 16S rRNA gene sequencing. Generalized linear mixed model (GLMM) was used to identify differences.

RESULTS

Totally, 168 subjects were assessed for eligibility. Twenty-two patients were recruited in the longitudinal study. Eventually, 67 PISF samples from 24 implants of 12 patients were collected and analysed. Peri-implant microbiome showed increasing diversity and complexity over time. Disease-associated genera Porphyromonas, Tannerella, Treponema and Prevotella dramatically increased from T1 to T3. The prediction model for clinical suppuration at T1 showed a high accuracy of 90%.

CONCLUSION

The dysbiosis of peri-implant microbiome increased with time during the two-year observation in patients with a history of periodontitis. Genera of Porphyromonas, Tannerella, Treponema and Prevotella were biomarkers of peri-implant mucositis. Microbiota at the early stage could predict subsequent microbial dysbiosis and clinical suppuration.

Effect of a Er, Cr:YSGG laser and a Er:YAG laser treatment on oral biofilm-contaminated titanium

OBJECTIVE

Implant surface decontamination is a challenging procedure for therapy of peri-implant disease. This study aimed to compare the effectiveness of decontamination on oral biofilm-contaminated titanium surfaces in Er:YAG laser, Er, Cr:YSGG laser, and plastic curette.

METHODOLOGY

For oral biofilms formation, six participants wore an acrylic splint with eight titanium discs in the maxillary arch for 72 hours. A total of 48 contaminated discs were distributed among four groups: untreated control; decontamination with plastic curettes; Er, Cr:YSGG laser; and Er:YAG laser irradiation. Complete plaque removal was estimated using naked-eye and the time taken was recorded; the residual plaque area was measured and the morphological alteration of the specimen surface was observed by scanning electron microscopy. The total bacterial load and the viability of adherent bacteria were quantified by live or dead cell labeling with fluorescence microscopy.

RESULTS

The mean treatment time significantly decreased based on the treatment used in the following order: Er:YAG, Er, Cr:YSGG laser, and plastic curettes (234.9±25.4 sec, 156.1±12.7 sec, and 126.4±18.6 sec, P=0.000). The mean RPA in the Er, Cr:YSGG laser group (7.0±2.5%) was lower than Er:YAG and plastic curettes groups (10.3±2.4%, 12.3±3.6%, p=0.023). The viable bacteria on the titanium surface after Er, Cr:YSGG laser irradiation was significantly lower compared to the decontamination with plastic curette (P=0.05) but it was not significantly different from the Er:YAG laser irradiation.

CONCLUSION

We found that Er:YAG laser and Er, Cr:YSGG laser irradiation were effective methods for decontaminations without surface alterations.

Role of New Hydrophilic Surfaces on Early Success Rate and Implant Stability: 1-Year Post-loading Results of a Multicenter, Split-Mouth, Randomized Controlled Trial

OBJECTIVE

 To compare early implant failure and implant stability of one-stage Hiossen ET III implants with its new hydrophilic (NH) surface, compared with Hiossen ET III implants with the sandblasted and acid-etched (SA) surface at 1-year follow-up.

MATERIALS AND METHODS

 This study was designed as a split-mouth, multicenter randomized controlled trial aimed to compare SA surface implants (SA group) and NH surface, (NH group). Outcomes were implant and prosthetic survival rates, complications, the insertion torque at implant placement, and implant stability quotient (ISQ) values.

RESULTS

 Twenty-nine patients (mean age 59.9 ± 11.3 years) were treated and followed up to 1 year after loading. No patient dropped out. Fifty-eight implants (29 SA group and 29 NH group) were placed. No implants or prostheses failed and no complications were experienced during follow-up. The mean insertion torque was 40.5 ± 3.23 (38.17-41.83) Ncm in the SA group and 40.48 ± 3.49 (38.02-41.98) Ncm in the NH group (p = 0.981). There was a statistically significant difference at the second week (T2) with higher values in the NH group (p = 0.041). Similar results were found in the maxilla (p = 0.045), but not in the mandible (p = 0.362). A positive correlation was found between initial insertion torque and ISQ with higher value in the NH group (0.73 vs. 0.66).

CONCLUSIONS

 NH implants are a viable alternative to SA surface, as they seem to avoid the ISQ drop during the bone remodeling phase.

Relationship between risk markers for cardiovascular disease and peri-implant diseases

Background

The aim of this paper is to explore the serum biochemical parameters also known as risk markers for cardiovascular system, in individuals who have received dental implant treatment, and to reveal risk factors for peri-implant diseases.

Methods

The study included 58 subjects with peri-implantitis, 49 subjects with peri-implant mucositis, and 49 healthy subjects. All the subjects were assessed in terms of both peri-implant clinical parameters—probing depth (PD), bleeding on probing (BOP), the type of prosthesis, gingival index (GI), keratinized mucosa width (KMW), and plaque index (PI)—and serum biochemical parameters (e.g., LDL cholesterol, HDL cholesterol, triglyceride, total cholesterol, vitamin D, uric acid, white blood cell (WBC), neutrophil, hemoglobin (Hb), and platelet counts).

Results

KMW was the lowest in the peri-implantitis group. Compared with the other groups, the peri-implantitis group showed significantly higher levels of triglyceride, uric acid, and WBC. The peri-implantitis group had the lowest level of vitamin D. Triglyceride and uric acid levels had positive correlations with peri-implant clinical parameters.

Conclusion

High levels of triglyceride and uric acid may pose a risk for both peri-implant diseases and cardiovascular diseases. Prior to dental implant surgery, patients’ serum biochemical parameters should be checked.

Effect of crown to implant ratio and implantoplasty on the fracture resistance of narrow dental implants with marginal bone loss: an in vitro study

Background

Peri-implantitis is a biological complication that affects soft and hard tissues around dental implants. Implantoplasty (IP) polishes the exposed implant surface, to decontaminate it and make it less prone to bacterial colonization. This study investigates whether a higher clinical crown-to-implant-ratio (CIR) reduces implant fracture resistance and whether implants are more fracture-prone after IP in the presence of 50% of bone loss.

Methods

Forty-eight narrow platform (3.5 mm) 15 mm long titanium dental implants with a rough surface and hexagonal external connection were placed in standardized bone-like resin casts leaving 7.5 mm exposed. Half were selected for IP. The IP and control groups were each divided into 3 subgroups with different clinical CIRs (2:1, 2.5:1 and 3:1). The implant wall width measurements were calculated using the software ImageJ v.1.51 through the analysis of plain x-ray examination of all the samples using standardized mounts. A fracture test was performed and scanning electron microscopy was used to evaluate maximum compression force (F_max) and implant fractures.

Results

IP significantly reduced the implant wall width (P < 0.001) in all reference points of each subgroup. F_max was significantly higher in the 2:1 subgroup (control = 1276.16 N ± 169.75; IP = 1211.70 N ± 281.64) compared with the 2.5:1 (control = 815.22 N ± 185.58, P < 0.001; IP = 621.68 N ± 186.28, P < 0.001) and the 3:1 subgroup (control = 606.55 N ± 111.48, P < 0.001; IP = 465.95 N ± 68.57, P < 0.001). Only the 2.5:1 subgroup showed a significant reduction (P = 0.037) of the F_max between the controls and the IP implants. Most fractures were located in the platform area. Only 5 implants with IP of the 2:1 CIR subgroup had a different fracture location (4 fractures in the implant body and 1 in the prosthetic screw).

Conclusions

IP significantly reduces the fracture resistance of implants with a 2.5:1 CIR. The results also suggest that the CIR seems to be a more relevant variable when considering the resistance to fracture of implants, since significant reductions were observed when unfavorable CIR subgroups (2.5:1 and 3:1 CIR) were compared with the 2:1 CIR samples.