Objective : The objective of the present study was to evaluate histomorphometrically, in adult dogs, the effect of sintering carbonate apatite (500 CA or 700 CA) at 500℃ or 700℃, with or without low-intensity pulsed ultrasound (LIPUS) irradiation at 3 MHz (exposed for 15 min every day) for 7 days in a bone cavity.
Material and Methods : After three months of bone healing after tooth extraction, six bone cavities were created in parts P1, P2, P3 and M1 of ten adult dogs. Six experimental conditions were established : G1 : control (β-TCP) ; G2 : β-TCP+LIPUS ; G3 : 500 CA, G4 : 500 CA+LIPUS, G5 : 700CA and G6 : 700 CA+LIPUS. After 14 or 28 days, the dogs were euthanized. Their lower jaws were removed, fixed, stained by Villanueva Goldner-stain, dehydrated and embedded in MMA resin. Semi-serial sections were obtained and examined with light microscopy.
Results : Histomorphometric analyses of the bone cavity grafted into Ti-mesh tubes with G4 revealed 5.72% (mean) new vital bone at two weeks. LIPUS significantly increased new bone formation with 500 CA, although it did not affect the resorption of the materials except 700 CA(G6). At four weeks, however, no significant influences were observed ; G4 was as effective as β-TCP in terms of new bone formation.
Conclusion : The results of the present study suggest that 500 CA graft material and LIPUS irradiation present additional advantages in new bone formation at two weeks in bone cavities in the lower jaws of adult dogs.
To investigate whether the surface topography of dental implants affects bone loss around the implants, we installed Brånemark implants with two different surface roughnesses : a smooth machined surface and a rough surface created by anodic oxidation, on an adjacent area in identical patients, and examined marginal bone level radiographically.
The study sample consisted of 21 patients (14 men and 7 women). Sixty implants were installed, 30 with a smooth surface and 30 with a rough surface. Thirty-six implants were submerged, and 24 implants were placed for immediate loading. The marginal bone level was radiographically examined at implant installation, and at 1, 3 and 5 years after installation. The Wilcoxon signedrank test was used to test the significance of marginal bone loss of each surface group.
The difference between the two implant surfaces in marginal bone loss was not statistically significant at 1 year (p=0.796), 3 years (p=0.357) and 5 years (p=0.518) in the submerged group, nor at 1 year (p=0.180), 3 years (p=0.357) and 5 years (p=0.172) in the immediately loaded group. However, there were some cases with large bone loss in rough surfaces associated with peri-implantitis.
The purpose of this study was to evaluate the risk factors of the loss of osseointegration (late failure) of Brånemark implants (Nobel Biocare, Göteborg, Sweden) with two different surfaces : a relatively smooth machined surface and a rougher surface created by anodic oxidation. We statistically carried out a clinical examination on those implants : 443 implants with a smooth surface and 1,008 implants with a rough surface.
The results are summarized as follows :
1. Seven implants with a smooth surface (1.6%) and five implants with a rough surface (0.5%) lost their osseointegration within one year after the fitting of superstructures. There was a significant difference between them.
2. Age, primary stability and the healing period between implant installation and abutment connection did not affect late failure in the smooth and rough surface implants.
3. In the smooth surface implants, the prognosis of implants of 10 mm or less in length, 5 mm in diameter and installed in the posterior region of the mental foramen in the mandible was significantly poor.
4. In the rough surface implants, the prognosis of implants of 7 mm was significantly poor.
Prosthetic complications such as resin or porcelain veneer fractures of superstructures have occurred frequently during long-term follow-up after implant treatment. In this study, we focused on the main occluding areas according to Kato et al. (1996), investigated these areas in case of free-end missing, and examined the factors relating to the main occluding areas with veneer fractures of the implant superstructures.
Seventy superstructures of 38 patients treated for partial free-end missing both in the maxilla and the mandible were examined for the site of the implant prosthesis, the situation of the antagonist, the presence and the site of the veneer fracture of the superstructure, the maximum bite force and the occlusal contact area. To assess the location of the main occluding area, each subject was instructed to clench a test piece freely on the left and right side, alternately. This study was approved by the Tokushima University Hospital Clinical Research Ethics Committee (approval number 974) and informed consent was obtained from the patients.
A total of 58 cases of each of the left and right sides in 38 patients were divided into 12 superstructures fabricated as short-arch (SA : extended to first molar) and 46 superstructures as full-arch (FA : extended to second molar). In the SA group, 16.7% of the main occluding areas were on the second premolar and 83.3% on the first molar. Veneer fractures occurred in 6 superstructures, and the main occluding areas for all fractures were located on the first molars. In the FA group, 13.0% of the main occluding areas were on the second premolar, 65.2% on the first molar and 21.8% on the second molar. In this group, veneer factures had occurred in 12 superstructures, and 50% were coincident with main occluding areas.
This study confirmed that the main occluding areas were present on the superstructures supported by implants in free-end missing cases ; many of them were found on the first molar as well as the natural dentition. Many of the veneer fractures of the superstructures were observed in the main occluding areas. Discriminant analysis showed that the veneer fractures of the superstructures particularly tended to occur in the cases in which the recovered dentition extended to the first molar, the main occluding area was located in the posterior part of the dentition, or the antagonist dentition was supported by implants.
When using an implant-supported prosthesis to restore defects in hard and soft tissue, ease of cleaning should be considered. To date, the combined use of tissue porcelain or hard resins to simulate gingival tissue with an implant-supported prosthesis has been reported, but the outcome of such cases has not been elucidated.
A 25-year-old woman visited our hospital complaining of esthetic dissatisfaction with the median maxillary region. She had congenital absence of the right maxillary lateral and central incisors associated with right cleft lip and palate. We extracted the right maxillary canine and left central incisor before performing implant treatment.
The results indicated a favorable short-term outcome for this patient in whom tissue porcelain was used with an implant-supported prosthesis, indicating the usefulness of manufacturing a provisional restoration. However, the requirements are the use of a fixed retrievable implantsupported prosthesis, sufficient understanding and cooperation from the patient concerning the need for frequent recalls, and the patient being able to perform self-maintenance.
Objective : In the author's facility, an oral care center was established in April 2012 to provide perioperative oral management services. An important duty of dentists is to ensure the absence of any source of infection in the oral cavity before the initiation of treatment, such as oncological therapies. This paper reports the results of a study on the current status of our inpatients with a history of implant therapy.
Methods : Among the 1,299 patients who visited the center within the 2-year period between April 2012 and March 2014 for perioperative oral management, those with a history of implant therapy were examined, focusing on the following items : 1)sex and age, 2)status of implant therapy, and use of periodic maintenance services, 3)disease scheduled to be treated, and scheduled chemotherapy or craniocervical radiotherapy, and 4)examination results and course after implant therapy.
Results : The numbers of males and females were 14 and 10, respectively, with a median age of 70.5, ranging from 56 to 85. The number of implants was 1 to 9, with a median of 3. Only half of the patients used maintenance services. Malignant tumor was present in 21 cases, accounting for 80% of diseases scheduled to be treated. Chemo- and craniocervical therapies were required in 10 and 2 cases, respectively. The course was favorable in 14 and poor in 10 ; 2 of the latter needed implant removal.
Conclusion : Systemic diseases may develop even in patients who have undergone implant therapy, occasionally involving serious side effects, depending on their conditions. Although clear standards do not exist, it may be necessary to consider systemic conditions when examining the appropriateness of implant removal. Perioperative oral management may play an important role in the management of patients not using periodic maintenance services after implant therapy.
A protocol for the treatment of complications involving the maxillary sinus after dental implant placement has not yet been established. Six patients (2 males, 4 females ; mean age 60.8 years) treated for maxillary sinus complications after dental implant placement in our department over the past 10 years were analyzed statistically, and methods of preventing and treating maxillary sinus complications were considered.
Two of the six patients experienced displacement of the dental implant body into the maxillary sinus, and five patients developed maxillary sinusitis because of extrusion and displacement of the dental implant and leakage of bone substitute into the maxillary sinus noted upon initial examination. Four patients complained of swelling and pain at the buccal region. The two patients with dental implant displacement had few subjective symptoms. Retrieval of dental implants displaced into the maxillary sinus was planned for two patients, but the dental implant of one patient was accidentally swallowed before the operation.
Treatment of the maxillary sinusitis with irrigation of the maxillary sinus and administration of antibiotic medication were effective, and no signs of residual sinus infection were observed in any of the patients after treatment. Our treatment procedures may prevent the need for removal of dental implants and bone substitute.