• The Journal of Advanced Prosthodontics
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• v.6 no.5
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• pp.325-332
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• 2014

PURPOSE. The aim of this review was to analyze the evaluation criteria on mandibular implant overdentures through a systematic review and suggest standardized evaluation criteria. MATERIALS AND METHODS. A systematic literature search was conducted by PubMed search strategy and hand-searching of relevant journals from included studies considering inclusion and exclusion criteria. Randomized clinical trials (RCT) and clinical trial studies comparing attachment systems on mandibular implant overdentures until December, 2011 were selected. Twenty nine studies were finally selected and the data about evaluation methods were collected. RESULTS. Evaluation criteria could be classified into 4 groups (implant survival, peri-implant tissue evaluation, prosthetic evaluation, and patient satisfaction). Among 29 studies, 21 studies presented implant survival rate, while any studies reporting implant failure did not present cumulative implant survival rate. Seventeen studies evaluating peri-implant tissue status presented following items as evaluation criteria; marginal bone level (14), plaque Index (13), probing depth (8), bleeding index (8), attachment gingiva level (8), gingival index (6), amount of keratinized gingiva (1). Eighteen studies evaluating prosthetic maintenance and complication also presented following items as evaluation criteria; loose matrix (17), female detachment (15), denture fracture (15), denture relining (14), abutment fracture (14), abutment screw loosening (11), and occlusal adjustment (9). Atypical questionnaire (9), Visual analog scales (VAS) (4), and Oral Health Impact Profile (OHIP) (1) were used as the format of criteria to evaluate patients satisfaction in 14 studies. CONCLUSION. For evaluation of implant overdenture, it is necessary to include cumulative survival rate for implant evaluation. It is suggested that peri-implant tissue evaluation criteria include marginal bone level, plaque index, bleeding index, probing depth, and attached gingiva level. It is also suggested that prosthetic evaluation criteria include loose matrix, female detachment, denture fracture, denture relining, abutment fracture, abutment screw loosening, and occlusal adjustment. Finally standardized criteria like OHIP-EDENT or VAS are required for patient satisfaction.

• The Journal of Advanced Prosthodontics
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• v.11 no.3
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• pp.147-154
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• 2019

PURPOSE. This study aimed to evaluate the effect of two different implant-abutment connection structures with identical implant design on peri-implant bone level. MATERIALS AND METHODS. This clinical study was a patient-blind randomized controlled trial following the CONSORT 2010 checklists. This trial was conducted in 24 patients recruited between March 2013 and July 2015. Implants with internal friction connection were compared to those with external hex connection. One implant for each patient was installed, replacing the second molar. Implant-supported crowns were delivered at four months after implant insertion. Standardized periapical radiographs were taken at prosthesis delivery (baseline), and one year after delivery. On the radiographs, distance from implant shoulder to first bone-to-implant contact (DIB) and peri-implant area were measured, which were the primary and secondary outcome, respectively. RESULTS. Eleven external and eleven internal implants were analyzed. Mean changes of DIB from baseline to 1-year postloading were 0.59 (0.95) mm for the external and 0.01 (0.68) mm for the internal connection. Although no significant differences were found between the two groups, medium effect size was found in DIB between the connections (Cohen's d = 0.67). CONCLUSION. Considering the effect size in DIB, this study suggested the possibility of the internal friction connection structure for more effective preservation of marginal bone.

• Imaging Science in Dentistry
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• v.54 no.2
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• pp.171-180
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• 2024

Purpose: This study was conducted to identify the typical sites and patterns of peri-implant bone defects on cone-beam computed tomography (CBCT) images, as well as to evaluate the detectability of the identified bone defects on panoramic images. Materials and Methods: The study population included 114 patients with a total of 367 implant fixtures. CBCT images were used to assess the presence or absence of bone defects around each implant fixture at the mesial, distal, buccal, and lingual sites. Based on the number of defect sites, the presentations of the peri-implant bone defects were categorized into 3 patterns: 1 site, 2 or 3 sites, and circumferential bone defects. Two observers independently evaluated the presence or absence of bone defects on panoramic images. The bone defect detection rate on these images was evaluated using receiver operating characteristic analysis. Results: Of the 367 implants studied, 167 (45.5%) had at least 1 site with a confirmed bone defect. The most common type of defect was circumferential, affecting 107 of the 167 implants(64.1%). Implants were most frequently placed in the mandibular molar region. The prevalence of bone defects was greatest in the maxillary premolar and mandibular molar regions. The highest kappa value was associated with the mandibular premolar region. Conclusion: The typical bone defect pattern observed was a circumferential defect surrounding the implant. The detection rate was generally higher in the molar region than in the anterior region. However, the capacity to detect partial bone defects using panoramic imaging was determined to be poor.

• Journal of Periodontal and Implant Science
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• v.52 no.6
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• pp.479-495
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• 2022

Purpose: Rodent models have emerged as an alternative to established larger animal models for peri-implantitis research. However, the construct validity of rodent models is controversial due to a lack of consensus regarding their histological, morphological, and biochemical characteristics. This systematic review sought to validate rodent models by characterizing their morphological changes, particularly marginal bone loss (MBL), a hallmark of peri-implantitis. Methods: This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A literature search was performed electronically using MEDLINE (PubMed), and Embase, identifying pre-clinical studies reporting MBL after experimental peri-implantitis induction in rodents. Each study's risk of bias was assessed using the Systematic Review Center for Laboratory animal Experimentation (SYRCLE) risk of bias tool. A meta-analysis was performed for the difference in MBL, comparing healthy implants to those with experimental peri-implantitis. Results: Of the 1,014 unique records retrieved, 23 studies that met the eligibility criteria were included. Peri-implantitis was induced using 4 methods: ligatures, lipopolysaccharide, microbial infection, and titanium particles. Studies presented high to unclear risks of bias. During the osseointegration phase, 11.6% and 6.4%-11.3% of implants inserted in mice and rats, respectively, had failed to osseointegrate. Twelve studies were included in the meta-analysis of the linear MBL measured using micro-computed tomography. Following experimental peri-implantitis, the MBL was estimated to be 0.25 mm (95% confidence interval [CI], 0.14-0.36 mm) in mice and 0.26 mm (95% CI, 0.19-0.34 mm) in rats. The resulting peri-implant MBL was circumferential, consisting of supra- and infrabony components. Conclusions: Experimental peri-implantitis in rodent models results in circumferential MBL, with morphology consistent with the clinical presentation of peri-implantitis. While rodent models are promising, there is still a need to further characterize their healing potentials, standardize experiment protocols, and improve the reporting of results and methodology.

• The Journal of Advanced Prosthodontics
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• v.8 no.2
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• pp.150-157
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• 2016

PURPOSE. The modified lateral-screw-retained implant prosthesis (LSP) is designed to combine the advantages of screw- and cement-retained implant prostheses. This retrospective study evaluated the mechanical and biological complication rates of implant-supported single crowns (ISSCs) inserted with the modified LSP in the posterior region, and determined how these complication rates are affected by clinical factors. MATERIALS AND METHODS. Mechanical complications (i.e., lateral screw loosening [LSL], abutment screw loosening, lateral screw fracture, and ceramic fracture) and biological complications (i.e., peri-implant mucositis [PM] and peri-implantitis) were identified from the patients' treatment records, clinical photographs, periapical radiographs, panoramic radiographs, and clinical indices. The correlations between complication rates and the following clinical factors were determined: gender, age, position in the jaw, placement location, functional duration, clinical crown-to-implant length ratio, crown height space, and the use of a submerged or nonsubmerged placement procedure. RESULTS. Mechanical and biological complications were present in 25 of 73 ISSCs with the modified LSP. LSL (n=11) and PM (n=11) were the most common complications. The incidence of mechanical complications was significantly related to gender (P=.018). The other clinical factors were not significantly associated with mechanical and biological complication rates. CONCLUSION. Within the limitations of this study, the incidence of mechanical and biological complications in the posterior region was similar for both modified LSP and conventional implant prosthetic systems. In addition, the modified LSP is amenable to maintenance care, which facilitates the prevention and treatment of mechanical and biological complications.

• The Journal of the Korean dental association
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• v.51 no.12
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• pp.643-649
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• 2013

The aim of this study was to achieve the healing of peri-implantitis defects and the hard tissue regeneration using the augmentation of a xenograft on defect site. Two patients were treated with the surgical approach. With a full muco-periosteal flap elevation, the implant surfaces were exposed and taken the debridement of granulation tissue around the abutment. Each surface of the abutments was prepared with the air-abrasive device (PerioFlow$^{(R)}$) for decontamination. Bovine-derived bone mineral (Bio-Oss collagen$^{(R)}$) was then used to fill the defects, and no membrane was placed on the grafting site. Radiographs and clinical photo was taken to compare from baseline status. Within the limits of the present case, this case shows the significance of the surgical treatment of peri-implantitis. And this also verifies the stability of bovine-derived bone mineral and effectiveness of Air-abrasive device (PerioFlow$^{(R)}$).

• The Journal of the Korean dental association
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• v.53 no.5
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• pp.318-325
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• 2015

Peri-implantitis is defined as an inflammatory process affecting the tissues around an osseointegrated implant, resulting in the loss of the supporting bone. Microbial adherence and colonization appear to play a major role in the pathogenesis of periimplantitis. The decision regarding treatment strategies is based on the diagnosis. The severity of the peri-implant lesion and the treatment strategies must include mechanical cleaning (infection control) procedures. Mechanical instrumentation is widely used for the debridement of dental implants, but this may alter the titanium's surface properties. Therefore, selection of the type of instrumentation should be made depending on the type of surface to be debrided. Also, patients with dental implants must always be enrolled in a supportive therapy program.

• Imaging Science in Dentistry
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• v.50 no.2
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• pp.133-139
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• 2020

Purpose: This study compared 2 cone-beam computed tomography (CBCT) systems in the detection of mechanically simulated peri-implant buccal bone defects in dry human mandibles. Materials and Methods: Twenty-four implants were placed in 7 dry human mandibles. Peri-implant bone defects were created in the buccal plates of 16 implants using spherical burs. All mandibles were scanned using 2 CBCT systems with their commonly used acquisition protocols: i-CAT Gendex CB-500 (Imaging Sciences, Hatfield, PA, USA; field of view [FOV], 8 cm×8 cm; voxel size, 0.125 mm; 120 kVp; 5 mA; 23 s) and Orthopantomograph OP300 (Intrumentarium, Tuusula, Finland; FOV, 6 cm×8 cm; voxel size, 0.085 mm; 90 kVp; 6.3 mA; 13 s). Two oral and maxillofacial radiologists assessed the CBCT images for the presence of a defect and measured the depth of the bone defects. Diagnostic performance was compared in terms of the area under the curve (AUC), accuracy, sensitivity, specificity, and intraclass correlation coefficient. Results: High intraobserver and interobserver agreement was found (P<0.05). The OP300 showed slightly better diagnostic performance and higher detection rates than the CB-500 (AUC, 0.56±0.03), with a mean accuracy of 75.0%, sensitivity of 81.2%, and specificity of 62.5%. Higher contrast was observed with the CB-500, whereas the OP300 formed more artifacts. Conclusion: Within the limitations of this study, the present results suggest that the choice of CBCT systems with their respective commonly used acquisition protocols does not significantly affect diagnostic performance in detecting and measuring buccal peri-implant bone loss.

• The Journal of the Korean dental association
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• v.53 no.9
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• pp.618-627
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• 2015

Purpose : The purpose of this clinical study was to evaluate the effect of chelating and deproteinizing agent containing dental conditioning gel on alleviation of peri-implant mucosa inflammation. Methods: 36 patients with functionally loaded implants for at least 1 year and have clinical signs of peri-implant mucositis were recruited. At baseline, all implants received subgingival prophylaxis with ultrasonic scaler. In the test group, patients were provided a chelating and deproteinizing agent dental conditioning gel (Clinplant$^{(R)}$) and were given instructions to applicate it around the implants using an interdental brush for 2 weeks. Chlorhexidine and saline were provided to the positive control group and negative control group, respectively. The modified sulcus bleeding index (mSBI), modified plaque index (mPI), and probing pocket depth (PPD) were evaluated at baseline, 1 week, and 2 weeks. Results: In the Clinplant$^{(R)}$ and chlorhexidine group, mSBI (-0.81, -0.85 respectively; p<0.01), mPI (-0.46, -0.5 respectively; p<0.01), and PPD (-0.58, -0.48 respectively; p<0.01) at 2 weeks were significantly reduced from baseline. In the saline group, all the clinical parameters were reduced but there was no statistical significance. The saline may be attributed to the influence of prophylaxis at baseline. Conclusions: The present study demonstrated the beneficial clinical effects of chelating and deproteinizing agent containing dental conditioning gel to decrease peri-implant mucosa inflammation equivalent to chlorhexidine. This dental conditioning gel might be useful for alleviation of peri-implant mucosa inflammation.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.5
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• pp.607-619
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• 1999

Cortical support is an important factor, as the engagement of the fixture in strong compact bone offers an increased load-carrying capacity and initial stability. Because of the poor bone quality in the posterior mandible and other anatomic considerations, it has been suggested that implant fixtures be placed in these locations with apical engagement of the lingual cortical plate for so-called bicortication. The purpose of this investigation was to determine the effect of cortical engagements and in addition polyoxymethylene(POM) intramobile connector(IMC) of IMZ implant on implant load transfer in edentulous posterior segment of mandible, using three-dimensional (3D) finite element analysis models composed of cortical and trabecular bone involving single implant. Variables such as (1) the crestal peri-implant defect, (2) the apical engagement of lingual cortical plate, (3) the occlusal contact position (a vertical load at central fossa or buccal cusp tip), and (4) POM IMC were investigated. Stress patterns were compared and interfacial stresses along the bone-implant interface were monitored specially. Within the scope of this study, the following observations were made. 1) Offset load and angulation of fixture led to increase the local interfacial stresses. 2) Stresses were concentrated toward the cortical bones, but the crestal peri-implant defect increased the interfacial stresses in trabecular bone. 3) For the model with bicortication, it was noticed that the crestal cortical bone provided more resistance to the bending moment and the lingual cortical plate provided more support for the vertical load. But Angulation problem of the fixture from the lingual cortical engagement caused the local interfacial stress concentrations. 4) It was not clear that POM IMC had the effect on stress distribution under the present experimental conditions, especially for the cases of crestal peri-implant defect.