Air compressors are an indispensable part in today's dental treatment. Those used in dentistry are mostly installed either outside of, and far from, the treatment room or in a small and separate room under poor hygienic conditions. The reason is that such an installation in the treatment room likely poses environmental problems such as noise and vibration as well as being somewhat unsightly.
The procedure of sterlilization and disinfection is considered necessary and carried out for dental implant operations because those operations are a surgical treatment. However, when disinfection is tried as part of general dental treatment, dentists/oral surgeons have difficulties in obtaining high enough degrees of disinfection. They are largely due to the limitations about the equipment:where it is installed, specifically what it is designed to do,and so forth. As a result, most dentists/oral surgeons feel that disinfection of air discharged from air turbines to their satisfaction is almost impossible.
Not yielding to the prevailing feeling, the authors have made efforts to search for a better way of sterilization of air emitted from air turbines for treatment. We then found“SANKIN Sterilization Tank”useful and succeeded in disinfecting germs by applying the tank to an air turbine.
This thesis deals with the improvement of the efficiency of the endosseous implant and the subperiosteal implant introduced by YAMANE in 1974 by eliminating shortcomings, taking in advantages of these implants and by combining the two types of the implants. Our detailed calculation proves that the masticatory stress with this new type of implant is 1/4 of that with a conventinal endosseous implant and it is more stable and immovable.
This implant has been successfully employed for clinical treatment for a considerable period of time,but it has also been proved that clinical result can be affected with the depth of the center blade in the bone, and better result can be obtained with longer center blades. This has been validated through our experiments with large German shepards by implanting endosseous-subperiosteal implants into their jawbones and observing the clinical result of them.
Hydroxyapatite ceramics(HAP) are well known to be materials which have biocompatibility and osteoconductivity when implanted in bone tissue.We have already reported the responses of bone tissue to various types of HAP. In this paper, the osteoconductivity of granular HAP and the stability of HAP-bone complex are discussed.
Granular HAP were implanted in the bone marrow of rabbit tibia. Histological examination and quantitative analysis of bone tissue on the surfaces of HAP were performed on 4,7,10,14,21 days,1,3,6 and 12 months after implantation, and the following findings were obtained.
1.Osteoblasts were attached directly to the surfaces of HAP on the fourth day, followed by active bone formation, and about 90% of HAP in the bone marrow were surrounded by bone tissue on the 21th day.
2.HAP-bone complex in the bone marrow was stable in 3 months after implantation.
3.Bone resorption among HAP granules was evident on the 6-months and 12-months specimens.
Implant prosthetic treatment has gained it's footing as one of restoring methods for the loss of teeth in modern dentistry. However, we have encountered the various types of unexpected and undesirable reactions, of which main troubles are inflammatory,around the implant. Early finding and pertinent recovery treatment of undesirable reactions are able to preserve the function of implant and prevent the further serious side-effects.
In this report, we presented three successful cases in recovery treatment of troubled ITI endosseous implants. Our recovery treatment included elimination of peri-implant pocket combined with flap operation, application of HAP granules and gingival grafting. These procedures were thought to be applicable to endosseous implants as well as natural teeth.
We sometimes get lost in which way we should go, when we encounter a middle aged patient whose mouth is collapsed. Construction of complete dentures after extraction of teeth is relatively easy going.However, such a patient hesitates or rejects complete dentures. Then we must be able to restore not only function but also esthetics and emotional stability by applying comprehensive dentistry including attachment dentures and implants. In comprehensive dentistry, we must equip ourselves with high level of knowledge and technology.
In this clinical report, we tried to keep the boken-down teeth using endodontic endosseous pin implant after endodontic treatment, implanted ITI endosseous implants and constructed attachment dentures.
The patient became look younger and more active in her home and social life. Our comprehensive approach looks successful in appearance so far as 3 years postoperatively. However, we must keep eyes on the case from now on.
ITI implant is one of endosseous implants to which bone can contact directly. This implant is made of titanium(Ti 99.18%)and root part is plasma-splayed with titanium oxide. Besides, this implant is cylindrical in shape and has vents, so the retention forces seem to be great in amount.
The author applied ITI implants in maxillae of two patients. Superstructures were fixed to both residual teeth and implant abutments by means of screws and other types of attachments, that is, only operator can remove them when he needs modification and remake or repair.
Both cases were middle aged female patients who had mandibular dysfunction which disappeared by occlusal splints made after Dr. Jankelson's theory.These patients became stabler in emotion and are leading happy life at home and social activity.They testimony that they are using implanted sides as main chewing side and the X-ray films suggested this fact by white lines(lamina dura) along residual abutment teeth.
Hydroxyapatite ceramics(HAP)and β-tricalcium phosphate ceramics(TCP) have been reported to have biocompatibility and osteoconductivity when implanted into the bone, although there have been few studies on the comparative examination of HAP and TCP.
HAP and TCP were implanted into the bone marrow cavity of rabbit tibia. Histological examination and quantitative analysis of bone tissue on 1,2,3,4,6 weeks,3 and 6 months after the implantation exhibited the following findings：
1.Osteoblasts and new bone were attached directly to the surfaces of HAP and TCP on 1 week after the implantation, and the whole areas were filled with HAP-bone and TCP-bone complexes on 3 weeks specimens. These features indicate both HAP and TCP have good osteoconductivity in the early stage.
2.In the HAP group, HAP-bone complex was stable for 3 months after the implantation, although 6 months specimens showed a little resorption of new bone.
3.In the TCP group, new bone was resorbed from 4 weeks after the implantation, and 3 months specimens showed almost complete disappearance of new bone.
4.TCP was resorbed on 3 and 6 months specimens with the appearance of multinucleate giant cells on its surfaces.
Use of dental implants is playing an increasingly more significant role in oral rehabilitation.
The contact relation between the neck region of a dental implant and gingival epithelium is somewhat delicate because movement of unstable gingival mucosa and frenulum often gives rise to a down-growth of gingival epithelium, which makes the prognosis for the dental implant rather poor.
This report presents some cases for which a technique was applied to enlarge an area of stable keratinized gingiva together with an application of vestibuloplasty for dental implantation. The report also presents usefulness on an image analyzer in showing good results of enlargement on an area of stable gingival mucosa.
In conclusion, it is suggested that the technique applied is highly useful for dental implantation.
Endosseous implant has made sure its clinical position as one of restorative treatments.
There exist considerable literatures on treating partial anodontia by using conventional prosthetic procedures, but few studies by using endosseous implant have been reported. This article presented a partial anodontia case treated by ITI endosseous implant.
The following findings were obtained;
1. Treatment for partial anodontia using endosseous implant with rigid-removable superstracture is more suitable and able to give patients more esthetic and psychological satisfaction than using removabled partial denture.
2. Implant appears to be able to support a long spanned rigid-removable superstructure.
3.The examination of mandibular movement and EMG showed no problem in function up to this date.
AP liner composing of hydroxyapatite and zinc oxide(Taihei Chemical Industrial comp., Osaka)was developed for the purpose of a liner material.To evaluate a cell toxity and a harm to the vital pulp tissue, both an in vivo and an in vitro study.
In an in vitro study, a lined L-cell was used(adopted)for a cell toxity screening test.L-cells were cultured in α-MEM supplemented with 10% fetal bovine serum and antibiotics. After 24 hours of subculture, test materials of 0.2g were incubated in the medium after sterilization. The number of the cells were counted by an electronic cell counter every 24 hours by trypsinization. Although carboxyrate cement and zinc oxide eugenol cement affected the cell growth, AP liner did not significantly suppress a cell growth and activity comparing with control culture.
In an in vivo study,10 dogs (40 canine teeth,20 of each for control and experimentation)were performed under general anesthesia and then sacrificed at 2 weeks and 4 weeks after operation. The specimens were made in the routine manner after decalcification.
Congestion due to operation was observed but no other change was recognized at 2 weeks and no obvious change was observed at 4 weeks.
AP liner had no harm to the vital pulp tissue comparing with a calcium hydroxyoxide liner(dycal)on zinc phosphate cement(elite cement 100).
AP liner has a enough mechanical strength to reconstruct a cavity and to give a retention form.Judging from these results, we concluded that AP liner had no toxity and harm to the living cells either in vivo or in vitro and that was suitable material as a liner of a cavity.
The patients with partially edentulous regions which should be reduced in hight and width of alveolar ridges have been usually diagnosed as contraindication for implant modality because of less bone volume in implant site.
Bone volume of available ridge is a primarily important factor to decide whether the implant candidate is indicated or contraindicated.
Since 1977, we have tried to use both of implants such as dense hydroxyapatite granules particles as a bone-implants and blade-vent implants as a dental-implants for the patents with knife edge ridge who were generally contraindicated in endosseous implant.
To confirm safety and efficacy of these combined implant modalites, clinical trial study have been performed since 1977 in Nihon University Dental Hospital.
In this presentation,3 cases being selected as the representative among the patient's in the study,were presented for showing the treatment processes and long-term prognosis.
According to our impression from clinical experiences, the implant modality using both implants might widen the range of indication for endosseous implant with lesser risks.
It has been said that bone necrosis which occurs due to frictional heat can be prevented if a sufficient amount of coolant is irrigated when a cutting instrument of a low revolution speed is used. However,it is very difficult to cut a cortical bone at a low revolution speed which has been generally mentioned.
As for the frictional heat in cutting bones, it is reported as temperature at which necrosis of bones may occur due to cutting heat. But there are various values for this temperature, and they are not constant. And the relationship between the number of revolutions per minute and the amount of irrigation on cutting is not clear yet.
So, this time, the author has set that the temperature in the safety range in which it is thought that bone cells will not die out is 40℃, has measured the temperature which may be generated when cutting bones, by changing the number of revolutions and the amount of irrigation to a bone under a constant pressure and has investigated the relationship between heat elimination in cutting bones, the number of revolutions and the amount of irrigation.As a result, when a cutting instrument is used at the revolution speeds,5,000,10,000 and 35,000 r.p.m.and the amount of irrigation is 40 ml/min., the temperature is in the safety range in either case.
The operation technic is an important factor for the success of implant as well as the diagnosis, postoperative prognosis and the prosthetic consideration.
In this study, the factors which will affect the heat occurrence and distribution during bone preparation performed on an in vitro mandible model(ribs of pig)were considered.
The factors which were considered were:1)The amount of load placed on the bone through preparating bur;300,500 and 700 g.2) The rotating speed;500 rpm,1,000 rpm and 2,000 rpm.3)The application of water irrigation or not. For bone preparation, a speed adjustable rotating instrument with irrigation was used. A real-time thermography(NIPPON AVIONICS Co., LTD.)was used to observe the temperature and distribution of the heat which occurred in the bone and the temperature of a specific point within the bone were statistically analyzed.
The conclusions are as follows:
1. The effect of various load placed on the bur.
According as the load increased, the amount of heat occurence during preparation increased. For penetrating through the cortical bone, the cutting efficiency of the bur with 300gm load were the lowest and the heat distribution were widely spread out over the cortical bone. On the other hand with 500gm load, the temperature rised as the drilling depth increased within the cancellous bone.
2. The effect of rotating speed.
As the rotating speed of bur increased both in cortical or cancellous bone layer, the temperature rised higher. On the contrary preparation period decreased.
3. The effect of water irrigation.
Preparating the cortical bone, water irrigating showed a significant effect. But not significant incase of cancellous bone.