We applied the image processing system by Macintosh Ⅱ computer to determination of implantation's prognosis on radiographs.And we were content with the results.Our systems were,Hard/Macintosh Ⅱ ci,RAM 8 MB,Hard disk 8 OMB (Apple), Removable hard disk 44 MB (SyQuest SQ-44). 13” color RGB moniter(Apple), Color video board(Raster Ops 24 STV), Scanner board(Barneyscan), 8 mm CCD(Sony), GT 6000 (Epson),Quick Scan(Barneyscan)Soft/Ultimagel.41 JP (graftek, IMI), Image 1.31(NIH, PDS), Media Grabber(Raster Ops), Color Magican Ⅲ (Three's), Photoshop(Adobe), Quick Scan V.2.1(Barneyscan), Excel 2.2(Microsoft), etc.
We experimented on one implant recovery case of 6, 7 removed 2 root type implants that were filled HAP past(6:A hole) and covered by Gore-tex film. After 3 months, we remorved the Gore-tex film. We took 9 X-P dental films, from the just after the operation until the reoperation day. We took image processing (about 9 original pictures) with our system. Those image processing experimental results correlated well with the real view when we conformed to diagnosed A and B holes at the reoperation time, A hole was healing and B hole was not healing.
Those results were very accurate.
Edentulous and partial edentulous jaws can be reconstructed using Osseointegrated implant system with predicable long-term success.
The groups using the system participated in a prospective study of 101 partially edentulous patients between 26 and 85 years of age.
Clinical parameters, length of fixtures, bone quality and shape of implants sites, existence of movability gingival, influence on Osseointegration of inserted fixtures.
Initially 339 fixtures were placed and 312 remained in the study following prosthesis placement.
Fixtures were lost or unaccounted for because of nonintegration prior to prosthesis fabrication, infection,and failure. During prosthetic procedures, failure was primarily attributable to unfavorable bone quality and smaller fixture size.
We discussed the clinical device and improvement to deal with the complication.
Basically there are two types of blade implants for endoosseous implantation,single-and double-headed, and either is chosen depending on the situation.
On the presumption that this difference in the number of heads has an impact on the distribution of stress on the alveolar, we conducted stress analysis by photoelasticity examination, which is the most popular,on implants with single-and double-heads where they are planted horizontally and also where the necks are bent 20°. The photoelastic resin and hardener employed for the experiment are Epicoat 828 and triethylene-tetra-amine (TTA) respectively in the ratio of 100:8. The process of hardening was done at 50℃, and the mixture was cooled down slowly, taking four hours.
In the experiment, single-and double-headed blades were planted in the mixture with the heads horizontal and the necks being bent 20° in the direction of the mesial point, and a vertical weight of 0.20, and 40 kg was given to the blades.From the point of view of practitioners,we report the following findings obtained through this stress analysis.
From time to time we observe cases with several year histories after implantation in which the necks of metal blades are broken or cracked. Most of them are cases of single-head type, and the damage is often found near the botton of the implants especially when their necks are bent in the direction of the medial point.It can be said that stress is more likely to be concentrated causing fatigue of the metal of single-hended blades.
The secular changes following implant enthesis resemble the symptoms of periodontal disease. In recent years, periodontal disease has been reported to be a local infection caused by bacteria. Although the causes which lead to the removal of an implant are diverse, amidst the growing emphasis being placed on plaque control, we focused on bacterial flora in the gingival sulcus of implants, and compared its bacterial flora with that found in the gingival pocket of teeth with periodontal disease by examining the items indicated below.
1. Changes in the bacterial flora of the gingival sulcus of implants immediately following implant enthesis.
2. Changes in the bacterial flora of the gingival sulcus of implants following periodontal surgical procedures.
3. Effectiveness of irrigation of the gingival sulcus of implants.
4. Effectiveness of irrigation in cases of subperiosteal implants.
As a result of the above comparisons,the following conclusion were obtained.
1. As implants are susceptible to the adherence of bacteria during enthesis, at the time of recall, examination of bacteria within the gingival sulcus of the implant is considered to be necessary.
2. When implant periodontitis occurs and motile bacilli,gram negative bacilli and spirochetes are present, therefore it is desirable to take actions corresponding to periodontal disease.
3. A reduction in the present bacteria can be achieved by routine use of irrigation in the same manner as in cases of periodontal disease.
4. Bacteria present in deep tissue can be accommodated by irrigation and the delivery of antibiotics.
Reviewing the clinical evaluation reports on endosteal implants, there are not many,which evaluate the implants for a relatively long period and from objective viewpoints.
From 44 cases, to which alumina ceramic implants were applied in our department during the period from January 1982 to November 1990 and which are more than 5 years postoperative, 31 cases responding to recall were selected for the present study. Evaluation was made by the endosteal implant postoperative evaluation system in our department, and these cases were classified as Class 1 (good), Class 2 (fair), Class 3 (removal necessary), and Class 4 (removed).
The results were:13 cases in Class 1(41.9%), 9 cases in Class 2(29.0%), 2 cases in Class 3(6.5%), and 7 cases in Class 4 (22.6%). These results suggest that further modification is required for the alumina ceramic implant.
The following research was made with the hope that implants will function successfully as long as possible. The first step was to examine the comparison of bacteria flora between periodontal gingival pockets and implant gingival sulcus, and to research the relation between implant materials and bacteria numbers in implant sulcus.
52 implant cases and 35 pockets were used for this study. Bacteria flora was collected with a sterilized paper point at a depth ranging up to 14 mm.
The results are as follows:
1. Implant and periodontal disease gingival sulcus have very similar prognosis for long-term periods.
2. Increase of gram-negative rods and spirochaeta cause inferior prognosis.
3. Bacteria adheres easily to the implant material surface.
We investigated chronological changes in the mobility of two-piece apatite implants with a medical electric device, Periotest®, to identify the efficiency of Periotest and to establish clinical criteria for diagnosis with the device.
A total of 38 hydroxyapatite implants (APACERAM 2-Piece Implant type-S®,Pentax) were placed in the molar region of the mandible in 5 male patients and 10 female ones. They have been under observation since the fixture placement for up to five years. Almost all the implants have been in excellent condition up to the present. The implants stand alone, having no connection with any teeth; and the opposite teeth are normal.
Mobilities of the implants were chronologically measured by one examiner using Periotest. The variations of the site and direction for percussion were regulated as little as possible in each implant. In addition, we examined the influence of the length of the fixture, the diameter of fixture, and the length of abutment on the Periotest value(PTV).
The results are as follows.
1. Reproducible PTVs were obtained with the maximum variability of 1 in a series of percussions of the same implant.The PTVs within 30 days after the abutment placement ranged between -1 and -6 and the mean value of -3.5. Thereafter, they decreased slightly to the mean value of less than -4, and remained constant over the observation period. Periotest was useful in estimating the diagnosis for patients whose implants were border line in which radiography and manual testing may not be sensitive enough to detect problems. Periotest seems to provide an effective examination for the two-piece apatite implant.
2. The PTVs were affected by the length of abutment and the diameter of the fixture, and less affected by the length of the fixture. To diminish the mobility of the implant we should select a fixture with a greater diameter.
AS-occlusal plane analyzer, developed by Sekiya, was applied to examine the occlusion of an implant rehabilitation case with poor prognosis, which had been treated at a dental clinic. It was diagnosed that the failure was caused by unfavorably unbalanced articulation with excessive occlusal curve of Spee. The case was then reconstructed in the following way and had excellent prognosis:
1. All of the lower prosthesis was removed.
2. IMZ implant was placed on number 46.
3. Mandibular fixed crown and bridge was fabricated,balancing with the 4-inch curve of the Spee.
4. Complete maxillary denture was set with fully balanced occlusion.
Generally speaking,an existance of keratinized attachment gingiva is needed for lasting success in implant.
Our experience with the use of fibrin adhesive (Tisseel®-kit, Austria, IMMUNO) on free gingival graft for getting attachment gingiva around the implant was reported.
Tisseel®-kit is a biological tissue adhesive consisting of highly concentrated fibrinogen,thrombin,and factor XIII.
We applied Tisseel®-kit in 44 cases of free gingival graft for adhesive material in Medical corporation Itou dental clinic.
The clinical results were good in 37 cases and fair in 7 cases.
We thought that conformation of free gingiva to the bed may have influence on the adhesive effect.
Side effects were not observed in any of the cases in which the fibrin adhesive was employed.
The results indicated that Tisseel®-kit is useful for adhesive material on free gingival graft.
We often encounter cases in which quality and quantity of bone is not adequate for implants due to bone resorption caused either by long-lasting severe periodontal disease or by dentures of poor fit. The maxillary sinus continues to expand with aging, and sinus expansion is accelerated when the maxilla becomes edentulous. As a result adequate bone for implants often remains only in the area of the cupid and maxillary tuberosity.
We have applied osseointegrated ITI Implants in maxillary tuberosity and have used them as distal abutments for superstructures. The following findings have been obtained by examination of 36 cases;
1. It is useful to use osseointegrated implants in the maxillary tuberosity when there is an inadequate amount of bone for implants.
2. Though implant surgery in the maxillary tuberosity is relatively difficult, satisfactory results can be achieved in general practice, provided that thorough X-ray examination and study model analysis are made preoperatively and careful surgical procedures are performed with the use of pilot holes.
3. In case the mucosa in the maxillary tuberosity is thickened, as is often observed,it should be reduced during implant surgery.
4. Even if the direction of implant insertion is slightly inclined, osseointegrated type of implants will have no clinical occlusion problem, when they are loaded with occlusal force.
5. There will be no problem in connecting osseointegrated implants and natural teeth with a fixed prosthesis, provided that natural teeth to be connected with implants are in good periodontal conditions and the purpose of connection is to increase the number of connected teeth.
6. T-scan system is a valuable method implant sinking detection.
Histopathological investigation on mandibular nerve injury caused by deep insertion of dental implants into dog mandibles, at one month post-implantation of polycapillary implants. Two implants with mandibular nerve injury were accidentally observed in histological specimens of the sixteen implants.
Case I showed axonotmesis caused by continuous pressure to the mandibular nerve and several traumatic neuromas, induced by repetitious mastication impact stress, were observed around the axonotmesis. Case II showed neurotmesis caused by mis-drilling with channel former bar,and an active recovery was observed around the residual nerve fibers.
From these histopathological investigations, it was obvious that continuous or repetitious compressive and/or tensile stress to the mandibular nerve may induce traumatic neuroma even under light mastication stress, which causes pain and paralysis. It is suggested that the implant with pain and/or paralysis should be removed or raised slightly as fast as possible.
The bone channeling method of Blade-vent implant, was difficult to standardize than root from implant but became standardized by a low speed engine for implant use. This method of bone channeling is the most important for bone healing after operation. Because the implant supporting power of after healing has begun from the top of cortical alveolar bone, we must avoid channeling the bone too much.
Then we studied the method of channel by SUMICIKON channel saw and used in the clinic. We obtained good results by this method.
Our members at the General Implant Research Center used two channeling methods on an epoxy block and sorted out the implant carrier.
After that, we compared two methods,a channel saw and a channel bar.
The results were as follow:
The channel saw method was more effective than the other, and was not related to the implant carrier. It was possible for us to gain a standardize bone channel with this routine.
To overcome the fear of patients who want to have dental implants, we considered that it is important to give them an objective evaluation of pain. And a VAS (visual analogue scales) measurement on pain was conducted for various implanted patients (20 males and 59 females) using a 100 millimeter (mm) horizontal line. The following results were obtained.
1. The VAS average for the implants was at 19±17 mm, extremely lower compared with that for the pulpitis and no difference was observed in pain between either sexes.
2. No VAS difference was recognized in age while female patients in their 60 s were recognized evidently larger (p＜0.05) on the VAS average than male patients in their 60 s.
3. As for the implant sites, no VAS difference was observed and no evident difference was recognized between the sexes.
4. Concerning the VAS difference by the implant materials, it was recognized that the Bladevent implant was obviously larger than Shape memory implant (p＜0.01) and Sumicikon implant (p＜0.05), the Physio odontoram implant was larger than Shape memory implant (p＜0.05) and the Subperiosteal implant was larger than Bioceram implant (p＜0.01). However, no difference was recognized between the sexes about the implant materials.
5. If the measurement results are explained for the VAS as an objective evaluation on pain to the patients during implant precounseling, the consent will be obtained from the patients.