• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.39
• /
• pp.2.1-2.6
• /
• 2017

Background: All clinicians are aware of the difficulty of installing a dental implant in posterior maxilla because of proximate position of maxillary sinus, insufficient bone width, and lower bone density. This study is to examine which factors will make the implantation in the posterior maxilla more difficult, and which factors will affect the postoperative implant stability in this region. Methods: Five hundred seventy-three fixtures on the maxilla posterior were included for this study from all the patients who underwent an installation of the dental implant fixture from January 2010 to December 2014 at the Department of Oral and Maxillofacial Surgery in Pusan National University Dental Hospital (Yangsan, Korea). The postoperative implant stability quotient (ISQ) value, fixture diameter and length, presence of either bone graft or sinus lift, and graft material were included in the reviewed factors. The width and height of the bone bed was assessed via preoperative cone beam CT image analysis. The postoperative ISQ value was taken just before loading by using the OsstellTM $mentor^{(R)}$ (Integration Diagnostics AB, Gothenburg, Sweden). The t test and ANOVA methods were used in the statistical analysis of the data. Results: Mean ISQ of all the included data was 79.22. Higher initial bone height, larger fixture diameter, and longer fixture length were factors that influence the implant stability on the posterior edentulous maxilla. On the other hand, the initial bone width, bone graft and sinus elevation procedure, graft material, and approach method for sinus elevation showed no significant impact associated with the implant stability on the posterior edentulous maxilla. Conclusions: It is recommended to install the fixtures accurately in a larger diameter and longer length by performing bone graft and sinus elevation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.5
• /
• pp.361-366
• /
• 2009

Purpose: The purpose of this retrospective report was to analyze long-term survival rate of sintered porous-surfaced dental implant ($Endopore^{(R)}$ Dental Implant system, Innova Corporation, Toronto, ON, Canada). Methods: 61 partially edentulous patients were received a total of 127 Endopore dental implants in the maxilla. Of the 127 implants, 24 implants were restored with individual (ie, non-splinted) crowns, while 103 implants were splinted to other implants. Medical records and radiographs were evaluated and analyzed by the cumulative survival rate, location of implants, implants length and diameter, crown/implant ratio and whether the implant was splinted. Chi squire test was used statistically. Result: Of the 127 implants, 8 implants (6.3%) were removed and and cumulative survival rate was 93.7%. Conclusion: Endopore implants showed satisfactory results after up to 8 years function periods in the edentulous posterior maxilla.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.43 no.2
• /
• pp.70-76
• /
• 2017

The purpose of this study was to perform a literature review of short implants in the posterior maxilla and to assess the influence of different factors on implant success rate. A comprehensive search was conducted to retrieve articles published from 2004 to 2015 using short dental implants with lengths less than 10 mm in the posterior maxilla with at least one year of follow-up. Twenty-four of 253 papers were selected, reviewed, and produced the following results. (1) The initial survival rate of short implants in the posterior maxilla was not related to implant width, surface, or design; however, the cumulative success rate of rough-surface short implants was higher than that of machined-surface implants especially in performance of edentulous dental implants of length <7 mm. (2) While bone augmentation can be used for rehabilitation of the atrophic posterior maxilla, short dental implants may be an alternative approach with fewer biological complications. (3) The increased crown-to-implant (C/I) ratio and occlusal table (OT) values in short dental implants with favorable occlusal loading do not seem to cause peri-implant bone loss. Higher C/I ratio does not produce any negative influence on implant success. (4) Some approaches that decrease the stress in posterior short implants use an implant designed to increase bone-implant contact surface area, providing the patient with a mutually protected or canine guidance occlusion and splinting implants together with no cantilever load. The survival rate of short implants in the posterior edentulous maxilla is high, and applying short implants under strict clinical protocols seems to be a safe and predictable technique.

• The Journal of Korean Academy of Prosthodontics
• /
• v.43 no.2
• /
• pp.191-203
• /
• 2005

Statement of problem. In Korea, the preliminary impression trays for dental and edentulous maxillae are manufactured on the base of the statistical value of Westerners. There had been less study on the dental and edentulous arches of Koreans. Purpose. The purpose of this study was to evaluate an average dental cast, preliminary impression trays, three-dimensional relation of dental and edentulous maxilla of Koreans Material and methods. The subjects for this study were 173 dental casts of maxilla (dental: 52, edentulous : 146) with ages $18\{\sim}60$ years old. Each of the master casts was measured 69 measuring points on the dental cast or maxilla, and 46 measuring points on the edentulous cast of maxilla with three-dimensional digital measuring machine. Each measuring points were analysed and were overlapped, that three dimensional dental graphic manufactured by CAD/CAM system. Results. 1. A standard of distribution to alveolar bone were width between left and right buccal border lines of the standard 3/4 line. The mean value of dental and edentulous casts were 67.27mm, 63.49mm respectively. 2. Morphological classification of dental casts were divided into three groups or V-shape, O-shape, U-shape, that proportion of distribution were 17%, 16%, 67%, respectively. Dimensional classification of the dental casts were divided into five groups of less than 63mm, 63 up to 65mm, 65 up to 67mm. 67 up to 69mm, more than 69mm, respectively. 3. Morphological classification of edentulous casts were divided into three groups or V-shape, O-shape, U-shape, that proportion of distribution were 18%, 17%, 65%, respectively Dimensional classification of the edentulous casts were divided into five groups of less than 57mm, 57 up to 61mm, 61 up to 65mm, 65 up to 69mm, more than 69mm, respectively. 4. Mean dental and edentulous cast of maxilla were overlapped, the proportion of bone resorption to alveolar bone is higher than that of palatal bone, its difference were higher anterior 2/4 area than posterior 3/4 area. Conclusion. It obtains information of preliminary impression trays for dental and edentulous maxilla of Koreans.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.31 no.5
• /
• pp.435-439
• /
• 2009

The peripheral ossifying fibroma(POF) is a relatively common, non-neoplastic gingival growth that is classified as a reactive hyperplastic inflammatory lesion. The clinical appearance of POF is generally a small, well-circumscribed, focal mass with a sessile or pedunculated base. The pathogenesis of this lesion is uncertain. POFs are believed to arise from cells of the periodontal ligament as hyperplastic growth of tissue that is unique to the gingival mucosa. Approximately 60% of POFs occur in the maxilla, and 55%-60% of all cases occur in the incisor-canine area. Most lesions are less than 2 cm in size. To our knowledge, huge POF of approximately 8 cm in size in the lower posterior edentulous ridge has not been previously described in the English literature. We report an unusually huge POF overlying the lower posterior edentulous ridge mucosa, along with long-term follow up result.

• 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.

• The Journal of Advanced Prosthodontics
• /
• v.11 no.2
• /
• pp.112-119
• /
• 2019

PURPOSE. Zirconia materials have been used for implant-retained restorations, but the stress distribution of zirconia is not entirely clear. The aim of this study is to evaluate the stress distribution and risky areas caused by the different design of zirconia restorations on the atrophic bone of the posterior maxilla. MATERIALS AND METHODS. An edentulous D4-type bone model was prepared from radiography of an atrophic posterior maxilla. Monolithic zirconia and zirconia-fused porcelain implant-retained restorations were designed as splinted or non-splinted. 300-N occlusal forces were applied obliquely. Stress analyses were performed using a 3D FEA program. RESULTS. According to stress analysis, the bone between the 1) molar implant and the 2) premolar in the non-splinted monolithic zirconia restoration model was stated as the riskiest area. Similarly, the maximum von Mises stress value was detected on the bone of the non-splinted monolithic zirconia models. CONCLUSION. Splinting of implant-retained restorations can be more critical for monolithic zirconia than zirconia fused to porcelain for the longevity of the bone.

• Journal of Periodontal and Implant Science
• /
• v.40 no.2
• /
• pp.56-60
• /
• 2010

Purpose: The sinus lift procedure requires detailed knowledge of maxillary sinus anatomy and the possible anatomical variations. This study evaluated the location and prevalence of maxillary sinus septa using computed tomography (CT). Methods: This study was based on the analysis of CT images for posterior maxilla which were obtained from patients who visited Chonbuk National University Dental Hospital during the period of June 2007 to December 2008. With the exclusion of cases presenting any pathological changes, 236 maxillary sinuses in 204 patients were retrospectively analyzed. The average age of the patients was 50.9. The cases were divided into two groups, an atrophy/edentulous segment and a non-atrophy/dentate segment, and maxillary sinus septa of less than 2.5 mm were not taken in-to consideration. The location of septa was also divided for analysis into 3 regions: the anterior (1st and 2nd premolar), middle (1st and 2nd molar) and posterior (behind 2ndmolar) regions. Results: In 54 (20.9%) of the 204 patients there were pathologic findings, and those patients were excluded from the analysis. Sinus septa were present in 58 (24.6%) of the 236 maxillary sinuses and in 55 (27%) of the 204 total patients. In the atrophy/ edentulous ridge group (148 maxillary sinuses), 41 cases (27.7%) were found, and 17 cases (19.3%) were found in the non-atrophy/ dentulous ridge group (88 maxillary sinuses). In terms of location, septa were found in 18 cases (27.3%) in the anterior, in 33 cases (50%) in the middle and in 15 cases (22.7%) in the posterior regions. Conclusions: In the posterior maxilla, regardless of type of ridge (atrophy/edentulous or non-atrophy/dentate), the anatomical variation of sinus septa is diverse in its prevalence and location. Thus, accurate information on the maxillary sinus of thepatient is essential and should be clearly understood by the surgeon to prevent possible complications during sinus lifting.

• The Journal of Korean Academy of Prosthodontics
• /
• v.61 no.4
• /
• pp.284-292
• /
• 2023

Stable posterior occlusal support is crucial for adequate masticatory function and facial aesthetics. In elderly patients over the age of 65, masticatory ability has a significant impact on nutritional intake and overall health. This case report presents a prosthetic treatment of an elderly patient with edentulous maxilla and bilateral posterior edentulous mandible. The upper jaw was restored with a complete denture to establish an ideal occlusal plane, and the three-dimensional positions of the mandibular implants were determined accordingly. The implants were placed through computer-guided implant surgery and were immediately loaded with fixed provisional restorations. The implant-fixed zirconia final restorations were inserted in the lower posterior region, and the occlusal surface of posterior artificial teeth in the upper denture was substituted with cobalt-chrome alloy to resist occlusal wear. The patient's posterior occlusal support and masticatory function were promptly restored through this treatment process, and long-term stability against wear was also obtained.

• The Journal of Korean Academy of Prosthodontics
• /
• v.56 no.1
• /
• pp.25-30
• /
• 2018

In edentulous patients, the advantages of prosthodontic therapy using oral implants include both stability and comfort. Advantages suggested for this approach include the prevention of mandibular bone resorption and increased masticatory function. Implant hybrid prostheses place 4 to 6 implants between the mental foramens, and cantilevers are used to replace the posterior teeth at both ends. The 85 - year - old female patient visited our clinic with complete edentulism in the maxilla and mandible. This article reports a satisfactory clinical and esthetic outcome of full mouth rehabilitation using removable complete denture in the maxilla and implant hybrid prosthesis in the mandible.