• Imaging Science in Dentistry
• /
• v.51 no.3
• /
• pp.251-260
• /
• 2021

Purpose: Dental implants are widely used for the rehabilitation of edentulous sites. This study investigated the occurrence of dental implant malpositioning as shown on post-implantation cone-beam computed tomography (CBCT) and to identify related factors. Materials and Methods: Samples with at least 1 malpositioned dental implant were collected from a central radiology clinic in Tehran, Iran from January 2017 to January 2019. Variables such as demographic characteristics, length and diameter of implants, type of implant, sites of implant insertion, different types of implant malpositioning problems (cortical plate perforation, interference with anatomical structures), angulation of the implant, and the severity of malpositioning were assessed. In addition, the incidence of implant fracture and over-drilling was evaluated. Data were statistically analyzed using the chi-square test, 1-sample t-test, and Spearman correlation coefficients. Results: In total, 252 patients referred for implant postoperative CBCT evaluations were assessed. The cases of implant malpositioning included perforation of the buccal cortical plate (19.4%), perforation of the lingual cortical plate (14.3%), implant proximity to an adjacent implant (19.0%), implant proximity to an adjacent tooth (3.2%), interference with anatomical structures(maxillary sinus: 18.3%, mandibular canal: 11.1%, nasal cavity: 6.3%, mental foramen: 5.6%, and incisive canal: 0.4%). Implant fracture and over-drilling were found in 1.6% and 0.8% of cases, respectively. Severity was categorized as mild (9.5%), moderate (35.7%), severe (37.7%), and extreme (17.1%), and 52.4% of implants had inappropriate angulation. Conclusion: CBCT imaging is recommended for detecting dental implant malpositioning. The most common and severe type of malpositioning was buccal cortex perforation.

• Journal of Periodontal and Implant Science
• /
• v.50 no.6
• /
• pp.379-391
• /
• 2020

Purpose: The aims of this study were to evaluate the 5-year cumulative survival rate (CSR) of implants placed with guided bone regeneration (GBR) compared to implants placed in native bone, and to identify factors contributing to implant failure in regenerated bone. Methods: This retrospective cohort study included 240 patients who had implant placement either with a GBR procedure (regenerated bone group) or with pristine bone (native bone group). Data on demographic features (age, sex, smoking, and medical history), location of the implant, implant-specific features, and grafting procedures and materials were collected. The 5-year CSRs in both groups were estimated using Kaplan-Meier analysis. Risk factors for implant failure were analyzed with a Cox proportional hazards model. Results: In total, 264 implants in the native bone group and 133 implants in the regenerated bone group were analyzed. The 5-year CSRs were 96.4% in the regenerated bone group and 97.5% in the native bone group, which was not a significant difference. The multivariable analysis confirmed that bone status was not an independent risk factor for implant failure. However, smoking significantly increased the failure rate (hazard ratio, 10.7; P=0.002). Conclusions: The 5-year CSR of implants placed in regenerated bone using GBR was comparable to that of implants placed in native bone. Smoking significantly increased the risk of implant failure in both groups.

• Journal of Periodontal and Implant Science
• /
• v.53 no.2
• /
• pp.145-156
• /
• 2023

Purpose: The significance of keratinized tissue for peri-implant health has been emphasized. However, there is an absence of clinical evidence for the use of a xenogeneic collagen matrix (XCM) to manage peri-implant mucositis and peri-implantitis. Therefore, the purpose of this study was to investigate outcomes after keratinized tissue augmentation using an XCM for the management of peri-implant diseases. Methods: Twelve implants (5 with peri-implant mucositis and 7 with peri-implantitis) in 10 patients were included in this study. Non-surgical treatments were first performed, but inflammation persisted in all implant sites. The implant sites all showed a lack of keratinized mucosa (KM) and vestibular depth (VD). Apically positioned flaps with XCM application were performed. Bone augmentation was simultaneously performed on peri-implantitis sites with an intrabony defect (>3 mm). The following clinical parameters were measured: the probing pocket depth (PPD), modified sulcular bleeding index (mSBI), suppuration (SUP), keratinized mucosal height (KMH), and VD. Results: There were no adverse healing events during the follow-up visits (18±4.6 months). The final KMHs and VDs were 4.34±0.86 mm and 8.0±4.05 mm, respectively, for the sites with peri-implant mucositis and 3.29±0.86 mm and 6.5±1.91 mm, respectively, for the sites with peri-implantitis. Additionally, the PPD and mSBI significantly decreased, and none of the implants presented with SUP. Conclusions: Keratinized tissue augmentation using an XCM for sites with peri-implant mucositis and peri-implantitis was effective for increasing the KMH and VD and decreasing peri-implant inflammation.

• The Journal of the Korean dental association
• /
• v.58 no.9
• /
• pp.583-589
• /
• 2020

If the implant is planted in the wrong position or direction, it is disadvantageous for stress distribution, and it is easy to cause complications such as screw loosening, abutment fracture, and implant fracture. If the position or orientation of the implant is not good, efforts should be made to minimize the problem through proper implant prosthetic treatment. In this article, the prosthetic method for facilitating future maintenance in cases with poor implant placement or orientation will be presented.

• Archives of Plastic Surgery
• /
• v.38 no.6
• /
• pp.808-814
• /
• 2011

Purpose: Despite wide clinical use of breast implants, there is continued concern about the lifespan of these devices. The causes of explantation were infection, deflation of implant and patient's want. The deflation of saline-filled breast implant was related to strength and durability of implant shell. The purpose of this study is to evaluate the clinical durability of saline-filled breast implant through the analysis of duration until deflation occurred, causes, incidence and influencing factors. Methods: Retrospective analyses were conducted on clinical records for 19 cases of deflation of saline-filled breast implant from 201 cases of breast reconstruction with saline-filled implant between May 1995 and June 2011. The authors had been analyzed the causes of deflation, survival duration, symptom, sign, nipple excision, volume of implant, saline filling, method of reoperation, breast cancer stage and combined capsular contracture. Results: The causes of deflation were attributed to the cases that cannot be evaluated the causes in 15 cases, fall down in 1 case, mammography in 2 cases, accidental needle injury in 1 case. Mean survival duration was 4 years and 5 months. The duration of survival was less than 1 year for 5 cases, 1 year to 10 years for 10 cases, more than 10 years for 4 cases. The volume between 201 and 250 cc of deflated breast implant was rated as high by 14.0 percent. The deflation rate of underfilled implants was 11.4 percent, adequate filled implants was 9.3 percent. None of overfilled implant was deflated. The deflation of smooth surface implant was 5 of 152 cases. Textured implant was 14 of 49 cases. The capsular contracture of non-deflated breast implant was 28 of 182 cases and that of deflated breast implant was 6 of 19 cases. Conclusion: The patients who underwent saline-filled breast implant implantation should be informed that their implant could deflate. The analysis of clinical durability and causes of deflation in breast implant was important for the prediction and prevention of reopeation. The authors could suppose the causes of deflation of saline-filled breast implant through history, duration of survival, inspection of the shell of implant.

• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.4
• /
• pp.346-353
• /
• 2011

Purpose: The peri-implant soft tissue is remodeled by the initial marginal bone resorption affecting the prognosis and esthetic result of treatment. Thus various designs on implant neck design are studied to preserve peri-implant bone. The purpose of this study is to review on the causes of initial marginal bone resorption, the configuration of peri-implant soft tissue, and the implant crestal module favorable in preserving peri-implant tissue. Materials and methods: The studies on the causes of initial marginal bone resorption and the implant crestal modules are researched and reviewed using Pubmed database. The implant crestal modules including one piece and two-piece implant, internal and external hex abutment, taper and butt joint connection, scalloped design abutment, and platform switching concept are reviewed. Results: A number of clinical and experimental studies preferred one piece implant to two-piece in preserving initial peri-implant tissue. For two piece implants, internal hex abutment and taper joint connection appear more favorable than external hex abutment and butt joint connection relatively. Controversial issues still exist on scalloped design requiring more studies on it. Although the rationale is not certain, the concept of platform switching seems favorable in preserving initial peri-implant tissue based on clinical and experimental studies. Conclusion: Each implant crestal module contains its own advantages and disadvantages with various controversial issues. In the aspect of preservation of initial peri-implant tissue, however, one-piece implant seems beneficial. In cases when two-piece implant is more appropriate due to prosthodontic concerns or any other problems, the application of platform switching concept, internal connection abutment, and taper joint connection may be favorable for the preservation of peri-implant tissues.

• Journal of Periodontal and Implant Science
• /
• v.32 no.2
• /
• pp.361-370
• /
• 2002

The aim of this study was to analyze various data of 120 non-submerged ITI implants placed in 64 korean adults. The data were retrieved from patients' charts and registered in the computer and coded for a statistical analysis. The results revealed that the most common type of edentulism was a distal extension case, and the largest number of implants were placed in the mandibular first molar position. Implants were placed more frequently in mandibular, posterior position than maxillary, anterior position, respectively. With respect to the implant diameter and length, an implant with 4.1mm in diameter and more than 10mm in length was the most common. Since a molar position was the most prevalent position for implant placement in korean patients, clinicians should be careful about implant diameter which can resist a strong occlusal force expected in the molar position. In addition, the distance to the mandibular canal and the floor of maxillary sinus should be considered to avoid possible damages, such as nerve injury and sinus perforation in selecting a proper implant length.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.21 no.2
• /
• pp.191-204
• /
• 2005

Traditionally, the implant treatment require load-free healing period of at least 3 months in the mandible and 6 months in the maxilla. But this long healing period provides patients with the discomfort and economical trouble. Many experiments has been attempted for the outcome of such disadvantage, so recently the immediate loaded implant is getting popularity. Several literature has been published for clinical success of immediate loaded implant. The studies for the success rate of immediate loaded implant in multi-way has been reporting, nevertheless, we don't have yet a probable success. Various studies have been practiced that the advantages and disadvantages associated with immediate loaded implant, and factors that may influence the success of immediate implant, including patient selection, type of bone quality, required implant length, structure of the implant, surgical skill, need for achieving primary stability, control of occlusal force, peri-implant bone activity. The objective of this study is to review the literature related to immediate loading of implants and to discuss factors that may influence this treatment modality, based on scientific evidence.

• The Journal of the Korean dental association
• /
• v.52 no.7
• /
• pp.408-415
• /
• 2014

Peri-implant diseases are inflammatory lesions, which include peri-implant mucositis and peri-implantitis. Peri-implant mucositis is described as the presence of inflammation in the mucosa around implants without any bone loss. By contrast, in peri-implantitis, besides the inflammation in the peri-implant mucosa, loss of supporting bone is also seen. Diagnosis of peri-implant diseases require the use of gentle probing(0.2 ~ 0.3N) to identify the presence of bleeding on probing, probing depth and suppuration, both signs of clinical inflammation. Radiographs are required to detect loss of supporting bone. Baseline probing measurements and high quality, long cone periapical radiographs should be obtained once the restoration of the implant is completed to make possible longitudinal monitoring of peri-implant tissue.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.10 no.1
• /
• pp.104-113
• /
• 2001

This article described a procedure for fabricating an esthetic gingival porcelain restoration as an implant-supported fixed prosthesis for edentulous maxilla. Alternative treatments for fully edentulous patients include an implant-supported overdenture or a fixed implant-supported prosthesis with bilateral distal cantilevers. But, from a functional and biomechanical point of view, the fixed implant-supported prosthesis with posterior cantilevers or implant-supported tissue-borne overdenture do not significantly improve masticatory effectiveness compared with a distributed implant restoration as a fixed implant-supported prosthesis. The fact that the prosthesis is supported by distributed implants over eight for edentulous maxilla in general, provides increased masticatory efficiency as a fixed restoration and similar gingival appearance with esthetic gingival porcelain. It is also detachable by dentist to allow easier after-care of soft tissue and the prosthesis.