Implant failure and clinical and radiographic outcomes after surgical treatment of peri-implantitis: A meta-analysis.

PURPOSE: To assess the implant failure rate and clinical and radiographic outcomes of implants affected by peri-implantitis that received surgical treatment. MATERIALS AND METHODS: A systematic search was conducted of three databases (PubMed, Embase and Cochrane Library) to identify studies that examined implant failure and biological outcomes after surgical peri-implantitis treatment, including ≥ 10 patients and reporting on a follow-up period of at least 12 months. Data and risk of bias were assessed qualitatively and quantitively. Surgical modalities were subdivided into reconstructive, non-reconstructive and combined. Meta-analyses were performed for implant failure, marginal bone level and probing pocket depth at 12 and 36 months with the respective subset of available data for each time and endpoint. RESULTS: A total of 45 studies with 3,463 treated implants were included in the quantitative evaluation. Meta-analyses revealed low implant failure rates of 1.2% (95% confidence interval 0.4%, -2.1%) and 4.2% (95% confidence interval 1.0%, -8.8%) at 12 and 36 months, respectively. No significant difference between the subgroups was observed at 12 months. At 36 months, reconstructive modalities showed a significantly lower implant failure rate (1.0%; 95% confidence interval 0.0%, 5.0%; P = 0.04, χ2(1) = 4.1) compared to non-reconstructive modalities (8.0%; 95% confidence interval 2.0%, 18.0%). The mean probing pocket depth was 3.71 mm (95% confidence interval 3.48, 3.94 mm) at 12 months and 3.63 mm (95% confidence interval 3.02, 4.24 mm) at 36 months. The mean marginal bone loss was 3.31 mm (95% confidence interval 2.89, 3.74 mm) at 12 months and 2.38 mm (95% confidence interval 1.01, 3.74 mm) at 36 months. No significant differences between the modalities were observed for bleeding on probing after either of these time points. Cumulative interventions during supportive therapy were reported in 9% of the studies. CONCLUSION: Surgical treatment of peri-implantitis results in a low implant failure rate in the short and medium term. No differences were noted between the different interventions with regard to failure rate. Surrogate therapeutic endpoints were improved after treatment, without significant differences between the different modalities. Therapeutic success and/or disease resolution and cumulative interventions during supportive therapy are seldom reported in the literature, but limited long-term outcomes are documented consistently.

Properties of three collagen scaffolds in comparison with native connective tissue: an in-vitro study.

PURPOSE: To evaluate collagen scaffolds (CS) in terms of their in vitro resorption behavior, surface structure, swelling behavior, and mechanical properties in physiologically simulated environments, compared with porcine native connective tissue. MATERIALS AND METHODS: Three test materials-one porcine collagen matrix (p-CM), two acellular dermal matrices (porcine = p-ADM, allogenic = a-ADM)-and porcine native connective tissue (p-CTG) as a control material were examined for resorption in four solutions using a high-precision scale. The solutions were artificial saliva (AS) and simulated body fluid (SBF), both with and without collagenase (0.5 U/ml at 37 °C). In addition, the surface structures of CS were analyzed using a scanning electron microscope (SEM) before and after exposure to AS or SBF. The swelling behavior of CS was evaluated by measuring volume change and liquid absorption capacity in phosphate-buffered saline (PBS). Finally, the mechanical properties of CS and p-CTG were investigated using cyclic compression testing in PBS. RESULTS: Solutions containing collagenase demonstrated high resorption rates with significant differences (p < 0.04) between the tested materials after 4 h, 8 h and 24 h, ranging from 54.1 to 100% after 24 h. SEM images revealed cross-linked collagen structures in all untreated specimens. Unlike a-ADM, the scaffolds of p-CM and p-ADM displayed a flake-like structure. The swelling ratio and fluid absorption capacity per area ranged from 13.4 to 25.5% among the test materials and showed following pattern: p-CM > a-ADM > p-ADM. P-CM exhibited higher elastic properties than p-ADM, whereas a-ADM, like p-CTG, were barely compressible and lost structural integrity under increasing pressure. CONCLUSIONS AND CLINICAL IMPLICATIONS: Collagen scaffolds vary significantly in their physical properties, such as resorption and swelling behavior and elastic properties, depending on their microstructure and composition. When clinically applied, these differences should be taken into consideration to achieve the desired outcomes.

Soft tissue-related complications around anterior implants: commentary and clinical checklist.

Implant-based rehabilitation is a clinical challenge, especially in the esthetic area. Numerous factors influence the outcome of the rehabilitation; however, the two main factors are the bone and soft-tissue deficiencies at the intended implant site. Peri-implant soft tissue complications can arise from a combination of factors that can be summarized as two categories: diagnostic errors and surgical planning management errors. Most of the complications can be corrected after each step of the treatment and even after the delivery of the prosthetic restoration with adequate soft tissue management in order to give the patient an esthetically pleasing outcome. The aims of this article were: to present the current literature, to propose a clinical checklist to guide clinicians in evaluating the prognosis of the treatment utilizing soft tissue grafting, and to illustrate a case series partially employing the proposed clinical checklist. The proposed checklist could be helpful in evaluating the prognosis of the treatment utilizing only soft tissue grafting. In clinical cases in which the prognosis is classified as good, soft tissue management could be a viable treatment option before attempting more radical procedures like implant removal.

Bone envelope for implant placement after alveolar ridge preservation: a systematic review and meta-analysis.

PURPOSE: To assess the dimensional establishment of a bony envelope after alveolar ridge preservation (ARP) with deproteinized bovine bone mineral (DBBM) in order to estimate the surgical feasibility of standard diameter implants placement without any additional augmentation methods. METHODS: PubMed, Embase and CENTRAL databases were searched for suitable titles and abstracts using PICO elements. Inclusion criteria were as follows: randomized controlled trials (RCTs) comprising at least ten systemically healthy patients; test groups comprised placement of (collagenated) DBBM w/o membrane and control groups of no grafting, respectively. Selected abstracts were checked regarding their suitability, followed by full-text screening and subsequent statistical data analysis. Probabilities and number needed to treat (NNT) for implant placement without any further need of bone graft were calculated. RESULTS: The initial database search identified 2583 studies. Finally, nine studies with a total of 177 implants placed after ARP with DBBM and 130 implants after SH were included for the quantitative and qualitative evaluation. A mean difference of 1.13 mm in ridge width in favour of ARP with DBBM could be calculated throughout all included studies (95% CI 0.28-1.98, t2 = 1-1063, I2 = 68.0%, p < 0.01). Probabilities for implant placement with 2 mm surrounding bone requiring theoretically no further bone augmentation ranged from 6 to 19% depending on implant diameter (3.25: 19%, RD = 0.19, C = 0.06-0.32, p < 0.01/4.0: 14%, RD = 0.14, C = 0.05-0.23, p < 0.01/5.0: 6%, RD = 0.06, C = 0.00-0.12, p = 0.06). CONCLUSION: ARP employing DBBM reduces ridge shrinkage on average by 1.13 mm and improves the possibility to place standard diameter implants with up to 2 mm circumferential bone housing; however, no ARP would have been necessary or additional augmentative bone interventions are still required in 4 out of 5 cases.

Literature review of aggregated evidence (umbrella review) on the allergy potential of chlorhexidine mouthrinse solutions.

OBJECTIVE: Chlorhexidine is the gold standard for chemical biofilm control in dentistry. As with all therapeutic agents, side effects should be considered, which may include allergic reactions. The present review focused on the allergy-causing potential of dental CHX mouthrinses. METHOD AND MATERIALS: Four databases were searched for systematic reviews related to chlorhexidine and dentistry (MEDLINE, Embase, Web of Science, and Scopus). Original papers available in the identified studies and meta-analyses were individually screened for allergy by both authors. RESULTS: An initial 804 studies were identified, of which 46 systematic reviews and the original papers described therein were ultimately analyzed. Only two reviews explicitly addressed the topic of allergy. In a total of 194 original studies and a total of 9,698 patients, no allergies were reported. In 44 control studies, the topic was touched upon, but only in connection with the inclusion and exclusion criteria and possible contraindications. CONCLUSIONS: The topic of "allergy" regarding chlorhexidine application as a mouth rinse in dentistry seems to be omnipresent. Nevertheless, true allergies to chlorhexidine in dentistry appear to be low to nonexistent. Precautions, however, should still be taken in practice and further studies should be envisaged, especially in patients with an alleged history of chlorhexidine contact allergy. (Quintessence Int 2022;53:808-814; doi: 10.3290/j.qi.b2841913 based on an original publication (in German) in Parodontologie 2022;33(1):59-69).

Tricalcium phosphate (-containing) biomaterials in the treatment of periodontal infra-bony defects: A systematic review and meta-analysis.

OBJECTIVES: This study aimed to investigate the additional clinical benefit of tricalcium phosphate (TCP) (-containing) biomaterials compared to open flap debridement (OFD) in periodontal infra-bony defects. DATA: A literature search was conducted in Pubmed, Embase and Cochrane library for entries published up to 14th July 2021. All randomized controlled trials (RCTs) that compared a TCP (-containing) material with OFD and studies that assessed a beta-TCP group alone, with vertical defect sites with PPD of ≥ 6 mm and/or presence of infra-bony defects of ≥ 3 mm and a minimum follow-up of 6 months were included. Risk of bias was assessed with the Oxford scale. The random-effects (RE) model was synthesized as differences between weighted average (MD) for probing pocket depth (PPD) and clinical attachment level (CAL) between TCP and OFD groups. An RE analysis was also performed for the beta-TCP group alone. STUDY SELECTION: Data from 16 RCTs were included in the analysis. Six studies that represented 151 patients and sites were selected for meta-analysis. The overall MD with 95% CI at 6 months was calculated to be -0.47 [-0.83, -0.12; P = 0.0087] and -1.06 [-1.67, -0.46; P = 0.0006] for PPD and CAL, respectively. Whereas MD at 12 months for PPD and CAL was -0.89 [-1.54, -0.23; P = 0.0078] and -1.25 [-1.85, -0.66; P<0.0001], respectively. All results were in favor of TCP (-containing) group over OFD. CONCLUSIONS: The results of the study suggest that the use of a TCP (-containing) material may have the potential for additional clinical improvement in PPD and CAL compared with OFD in infra-bony defects, given the limitations of the included evidence. CLINICAL SIGNIFICANCE: The use of TCP as a bone graft substitute is becoming increasingly common. Therefore, it would be advantageous if an adjunctive benefit in the regeneration of infra-bony defects could be demonstrated to facilitate material selection.

Origin of MMP-8 and Lactoferrin levels from gingival crevicular fluid, salivary glands and whole saliva.

BACKGROUND: Pathologically elevated levels of matrix metalloproteinase-8 (MMP-8) and Lactoferrin in oral fluids have been associated with the presence of gingivitis/periodontitis. This study aimed to assess the origin of MMP-8 and Lactoferrin in periodontitis patients and to identify the degree to which conventional clinical parameters correlate with their presence. METHODS: A total of ten periodontitis and ten healthy patients were included in this study. Whole saliva (stimulated and unstimulated), parotid/sublingual glandular fluid and gingival crevicular fluid from pockets and sulci were tested for MMP-8 and Lactoferrin and protein concentrations were quantified using an ELISA assay. Clinical parameters were checked for potential associations with MMP-8 and Lactoferrin levels. RESULTS: Periodontal patients presented higher concentrations of MMP-8 and Lactoferrin in pockets than other sources (P = 0.03). Lactoferrin measurement was higher in the parotid compared to sublingual glandular fluid in periodontitis patients (P = 0.03). Increased probing pocket depth was positively correlated with high MMP-8 and Lactoferrin levels. CONCLUSIONS: Periodontal pockets appear to be the major source of active matrix metalloproteinase and Lactoferrin, which also may also enter the oral cavity through the salivary glands. Since clinically healthy sites in periodontitis patients also had elevated biomarker levels, gingival crevicular fluid biomarker testing may be more predictive of future tissue breakdown than conventional clinical parameters.

Influence of preformed bone defects on key pathogens and bone loss during experimental peri-implantitis formation in a canine model.

PURPOSE: To determine the impact of experimentally preformed peri-implant crater-shaped bone defects on the evolution of in situ microbiota and development of bone defects compared to those induced over time by ligature placement only. METHODS: Implants were installed in the mandibles of eight dogs. Standardized bone defects were preformed in four test animals but not in the other four control animals, prior to implant (3.3 mm × 8 mm) installation. After 2 months of healing, peri-implantitis was induced with silk ligatures in both groups for 2 months. Microbial samples were obtained from implants and teeth for analysis at three time points (qPCR), and the average depths of the bone defects were measured. RESULTS: At the baseline, the total marker load of periodontal-pathogenic bacteria (TML) for teeth accounted for 5.2% (0-17.4%). After implant healing, TMLs for implants and teeth were comparable (7.1% [0.3-17.4%]). The TML of both groups was 3.5%, 2 months after ligature placement. Bone defects had a mean depth of 1.84 mm at preformed defects and 1.64 mm at control sites (P > 0.05). CONCLUSION: Preformed defects in the test group showed comparable results to the control group in terms of TML, the incidence of periodontal-pathogenic bacteria, and bone defect depth.

Evaluation of air polishing with a sterile powder and mechanical debridement during regenerative surgical periimplantitis treatment: a study in dogs.

OBJECTIVES: To evaluate the effectiveness of mechanical debridement and/or air polishing on the healing of ligature-induced buccal periimplantitis dehiscence defects in dogs. MATERIAL AND METHODS: Forty-eight implants were placed in the mandibles of twelve beagle dogs, and periimplantitis was induced for 2 months using ligatures. The resulting buccal dehiscence-type defects were surgically cleaned and augmented (xenogenic filler and resorbable membrane) according to one of the following treatments: (1) Cleaning with carbon curette (debridement - D) and guided bone regeneration (GBR/G): DG, (2) air polishing cleaning (A) and GBR: AG, (3) a combination of D/A/G: DAG, and (4) D/A without GBR: DA. After 2 months, histomorphometric and inflammatory evaluations were conducted. RESULTS: The median bone gain after therapy ranged between 1.2 mm (DG) and 2.7 mm (AG). Relative bone gain was between 39% (DG) and 59% (AG). The lowest inflammation scores were obtained in DA without GBR (5.84), whereas significantly higher values between 8.2 and 9.4 were found in the groups with augmentation. At lingual sites without defects, scores ranged from 4.1 to 5.9. According to ISO, differences above 2.9 were considered representative for irritative properties. CONCLUSIONS: All treatments resulted in partial regeneration of the defects. No treatment group showed a significantly (p < 0.05) better outcome. However, pretreatment with air polishing showed a tendency for less inflammation. Noteworthy, inflammation assessment showed an overall irritative potential after GBR in the evaluated early healing phase. CLINICAL RELEVANCE: Periimplantitis treatment still represents a big issue in daily practice and requires additional preclinical research in order to improve treatment concepts.

Quantitative measurements of aerosols from air-polishing and ultrasonic devices: (How) can we protect ourselves?

AIM: To assess the distribution and deposition of aerosols during simulated periodontal therapy. METHODS: A manikin with simulated fluorescein salivation was treated by four experienced dentists applying two different periodontal treatment options, i.e. air-polishing with an airflow device or ultrasonic scaling in the upper and lower anterior front for 5 minutes, respectively. Aerosol deposition was quantitatively measured on 21 pre-defined locations with varying distances to the manikins mouth in triplicates using absorbent filter papers. RESULTS: The selected periodontal interventions resulted in different contamination levels around the patient's mouth. The highest contamination could be measured on probes on the patient's chest and forehead but also on the practitioner's glove. With increasing distance to the working site contamination of the probes decreased with both devices. Air-polishing led to greater contamination than ultrasonic. CONCLUSION: Both devices showed contamination of the nearby structures, less contamination was detected when using the ultrasonic. Affirming the value of wearing protective equipment we support the need for universal barrier precautions and effective routine infection control in dental practice.

The Strange Case of a Broken Periodontal Instrument Tip.

This case report describes a rare case of a broken periodontal probe tip and its removal. A male patient presented himself in June 2019 due to a painful tooth in the upper left quadrant. The patient elected treatment in the dental school's student course. In October 2019, in preparation for full-mouth rehabilitation, a complete diagnostic status was performed, including radiographs. In this context, a metal-dense fragment was identified in the apical region of the (missing) tooth 45. It was diagnosed as the broken tip of a periodontal probe (type AE P OWB). Since a PCP-12 probe is generally used in-house, iatrogenic damage during the initial examination or student course could be excluded a priori. The patient was not able to remember any treatment that could be associated with the instrument's breaking. Since the probe fragment was palpable and a translocation could not be precluded, the patient agreed to its removal under local anesthesia, after a cone-beam CT. This article describes and discusses this particular case, with special emphasis on iatrogenic instrument fractures and their removal.

Gingival recession after scaling and root planing with or without systemic metronidazole and amoxicillin: a re-review.

BACKGROUND: Gingival recessions inevitably occur during healing after scaling and root planing, but synoptic data on this topic is still lacking. This review compared the recession formation with and without the administration of systemic antibiotics. OBJECTIVES: To evaluate the formation of recession with and without the administration of antibiotics during the healing after scaling and root planing. MATERIALS AND METHODS: This study re-analyzed publications that reported clinical attachment levels (CAL) and probing pocket depths (PD) up to January 2019, including the pivotal review by Zandbergen and co-workers (2013). Whereas these studies traditionally focused on PD and CAL, the present analysis compared recession formation (ΔREC) after adjunctive systemic administration of amoxicillin (amx) and metronidazole (met) during scaling and root planing (SRP) and SRP alone. The mean increase in ΔREC, if not reported, was calculated from CAL and PD values and statistically analyzed. Recession formation was compared after 3 and 6 months after therapy. Results were separately reported for chronic periodontitis (CP) as well as aggressive periodontitis (AP) cases. RESULTS: Recessions increased consistently between baseline and follow-up. In the AP group, median ΔREC was 0.20 mm after 3 months, irrespective of whether antibiotics were administered or not. After 6 months, median ΔREC increased to 0.35 mm after AB and remained stable at 0.20 mm with SRP alone. In the CP group, after 3 months with and without antibiotics, median ΔREC accounted for 0.30 mm and 0.14 mm, respectively. After 6 months, median ΔREC accounted for 0.28 mm (with AB) and 0.20 mm (without AB). The quantitative assessment by meta-analyses also yielded small values (≤ 0.25 mm) for the estimated differences in recession formation between AB and noAB; however, none of them reached statistical significance. CONCLUSIONS: Although a slight tendency towards higher recession formation after SRP in combination with AB could be observed in many studies, quantitative meta-analyses showed no clinically relevant difference in recession formation due to the administration of AB. In general, the description and discussion of recessions in the literature seems not to be a major focus so far. CLINICAL RELEVANCE: Since the preservation of gingival tissues is important by preventive and therapeutic means, e.g., when avoiding postoperative root sensitivity or performing regenerative surgery, these aspects should not be neglected. We thus suggest to report REC measurements along with PD and CAL values for more direct recession formation (ΔREC) assessments in the future.

Removal of failed dental implants revisited: Questions and answers.

Objectives: This narrative review is aiming on showing reasons for implant failure, removal techniques, and respective clinical considerations; further, the survival rate of implants in previous failed sites is examined. Materials and methods: Questions have been formulated, answered, and discussed through a literature search including studies assessing implant failure and removal up to 2018. Results: Studies describing reasons for implant failure, implant removal techniques, and the reinsertion of implants in a previous failed site (n = 12) were included. To date, peri-implantitis is the main reason for late implant failure (81.9%). Trephine burs seem to be the best-known method for implant removal. Nevertheless, the counter-torque-ratchet-technique, because of the low invasiveness, should be the first choice for the clinician. Regarding zirconia implant removal, only scarce data are available. Implantation in previously failed sites irrespective of an early or late failure results in 71% to 100% survival over 5 years. Conclusion: If removal is required, interventions should be based on considerations regarding minimally invasive access and management as well as predictable healing. (Post)Operative considerations should primarily depend on the defect type and the consecutive implantation plans.

Efficacy of chlorhexidine rinses after periodontal or implant surgery: a systematic review.

BACKGROUND: Biofilm management and infection control are essential after periodontal and implant surgery. In this context, chlorhexidine (CHX) mouth-rinses are frequently recommended post-surgically. Despite its common use and many studies in this field, a systematic evaluation of the benefits after periodontal or implant surgery is-surprisingly-still missing. OBJECTIVES: To evaluate the benefits of chlorhexidine rinsing after periodontal or implant surgery in terms of plaque and inflammation reduction potential. Furthermore, to screen whether the concentration changes or additives in CHX solutions reduce side effects associated with its use. MATERIALS AND METHODS: A systematic literature search was performed for clinical trials, which compared CHX rinsing after periodontal or implant surgery with rinsing using placebo, non-staining formulations, or solutions with reduced concentrations of the active compound. Four databases (Medline, PubMed, Embase, Cochrane) were searched up to June 2018. Two reviewers independently identified and screened the literature. RESULTS: From 691 titles identified, only eleven publications met the inclusion criteria and were finally included. Mainly early publications assessed the benefits of CHX over placebo rinsing, whereas more recent publications focused more on the evaluation of new formulations with regard to effectiveness and side effects. The use of CHX after surgery showed in general significant reduction in plaque (means of 29-86% after 1 week) and bleeding (up to 73%) as compared to placebo. No consensus, however, was found regarding the most beneficial CHX formulation avoiding side effects. CONCLUSION: Chlorhexidine rinsing helps to reduce biofilm formation and gingival inflammation after surgery. However, no additional reduction of periodontal probing depth over any given placebo or control solution could be found irrespective of whether CHX was used or not. The use of additives such as antidiscoloration systems (ADS) or herbal extracts may reduce side effects while retaining efficacy. CLINICAL RELEVANCE: Within the limitations of this review, it can be concluded that CHX may represent a valuable chemo-preventive tool immediately after surgery, during the time period in which oral hygiene capacity is compromised. To reduce the side effects of CHX and maintain comparable clinical effects, rinsing with less concentrated formulations (e.g., 0.12%) showed the most promising results so far.