The Video Overlay Monitoring System (Here in after referred to as VOLMS), which uses a personal computer to superimpose values from a commercially available monitor onto the intraoperative images and allows the storage and transfer of these images, has already been discussed in Part 2. This system also displays the results of various information processing which uses preoperative values as a reference. With the objective of obtaining possibly the most exact preoperative values, we have developed the following software for determining preoperative values that follows the process of estimating theses values, and installed this software in the VOLMS.
1. A monitoring interval was set to one minute,and the current values of four variables-systolic blood pressure (SBP),mean blood pressure (MBP), pulse rate (PR), and percutancously measured saturation of arterial oxygen (SpO₂)- were sequentially compared with their previous values.
2. The logical multiplications of three consecutively measured values for each variable were almost the same values in that environment.
The preoperative values were used as a reference that were obtained by this software during implant placement. These values were often observed throughout the surgery. In the information processing mode of the VOLMS, when the value of any of the variables exceeded an alarm level, the screen automatically switches to check its current value. The preoperative values, the upper and lower limits of an alarm, and a percentage change in the rate pressure product (RPP) from its preoperative value that were displayed on that screen became accurate for the patient. In addition, the advisory marks, which indicated changes from the preoperative values, became more rliable.

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From the standpoint of ensuring the safety of patients, monitoring is essential for intraoperative control. During implant placement, the operator is often respnosible for monitoring the patient's systemic status. Since the operator concentrates his/her attention on the operation itself, he/she might neglect intraoperative control.
The Video Overly Monitoring System (here in after referred to as VOLMS), which we developed, obtains vital signs from a commercially available monitor and processes them, and then superimposes the vital signs onto intraoperative images from a video camera and records these data on a VTR. Although this system proved to be useful in securing intraoperative safety and recording detailed data, the implementation was limited to “BX-2” (a monitor model manufactured by Nippon Colin Co., Ltd.) and the system was not ready for other models.
Then, all the software for the VOLMS was reviewed. In principal, the receiving software was modified so that it would conform to the respective protocols of serial data output from different monitor models. In addition, some changes were made to enable each parameter to be extracted or selected from the data series. The VOLMS was prepared for any model with output terminals for serial data. In this paper, the implementation of the VOLMS for “BP-308” (Nippon Colin's model) using medical engineering techniques, and an example of application of this system to the implant placement was reported.

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Chitosan is absorbed in vivo. Chitosan sol is produced by dissolving chitosan in a solution of malic acid. A chitosan film is formed by neutralization with the sodium polyphosphate solution, and then gelatinizes. The effects of the concentration of sodium polyphosphate solution on the tensile strength and elongation of chitosan film were examined. The chitosan sol dissolved in malic acid could not be neutralized with 2% sodium polyphosphate solution. By decreasing the concentration of sodium polyphosphate solution, the pH value of the neutralized chitosan decreased. By increasing the concentration of sodium polyphosphate solution, the tensile strength and elongation of chitosan film prepared with malic acid increased. By increasing the soaking period in physiological saline solution, the tensile strength and elongation of chitosan film prepared with malic acid decreased. When chitosan fibers were observed, the tensile strength decreased after the chitosan film was soaked. The tensile strength of chitosan film prepared with malic acid, followed by neutralization in a solution with a high concentration of sodium polyphosphate, showed higher tensile strength.

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Many studies have shown that titanium surface roughness or grooved orientation significantly affect the proliferation, migration, differentiation, and protein synthesis of human cultured cells especially of osteoblasts or osteoblast-like cells in vitro. However, few studies have compared the cell behaviors of osteoblasts and other human cells in vitro.
The purpose of the present study was to compare the proliferation and differentiation of human oral cells derived from different origins cultured on titanium plates and glass plates.
Bone cells derived from mandibular fragments, periodontal ligament (PDL) cells from mandibular first premolars, and gingival cells from the maxillary tuberosity region were obtained from the same orthognathic patient. These cells in the 4 th and 7 th passages were seeded (5×10³ cells/well) in 24-well plastic culture dishes with or without titanium plates or glass plates and incubation continued for 3, 6, 9, 12, and 15 days. At the end of each incubation period, three types of cells were used for the assays of DNA synthesis and alkaline phosphatase (ALP) activity.
The results were as follows:
1. Three types of cells cultured on plastic dishes, titanium plates, and glass plates produced DNA contents and ALP activity in a time-dependent manner.
2. The level of DNA contents and ALP activity produced from these cells were ranked in the following order, respectively, bone cells≒PDL cells＞gingival cells; bone cells≫PDL cells＞gingival cells.
3. The level of DNA contents and ALP activity produced from any type of cells cultured on different materials were ranked in the following order, plastic dish＞ titanium plate＞ glass plate.
4. Any type of cells in the 4 th passage produced a greater amount of DNA contents and ALP activity as compared to those in the 7 th passage.
These results suggested that bone cells in the 4 th passage cultured on titanium plates as well as plastic dishes show high activity for proliferation and differentiation.

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Various amounts of hydroxyapatite (HAP) contained chitin and chitosan films (CCF) were made of 70% (DA-70) and 96% (DA-96) deacetylated chitin and chitosan. These were implanted under the periosteum of rat calvaria and examined histopathologically. In HAP contained CCF made of DA-70, tissue reactions were characterized by marked inflammatory cell infiltration and granulation tissue formation.
In the calvaria, focal and marked bone resorption due to osteoclasts were observed in cases of CCF containing a large amount of HAP. On the other hand, in HAP contained CCF made of DA-96, inflammatory reaction was mild, and connective tissue encapsulation was observed. In addition, CCF containing a large amount of HAP showed the tendency to be resolved. In controls, on HAP contained CCF, histological changes were similar to those of each HAP contained CCF, but bone resorption was not found. These findings suggested that it was necessary to pay attention to HAP content when bone substitutes were made by combining DA-70 and HAP.

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Primary fixation is one of the most important factors in establishing adequate osseointegration between bone and fixture. The present study is an attempt to investigate the necessary removal torque of titanium alloy screws (d: 3.2 mm, l: 8 mm) inserted in the rabbit tibia with cortical and bicortical support. After 4, 8, and 16 weeks, the titanium alloy screws in nine animals were removed with a Tohnichi model 15 BTG-N torque gauge instrument. The torque necessary for removal of the implants was measured.
Then implants in the tibia were cut out in bloc with the surrounding cortical bone. They were fixed in formalin, dehydrated in alcohol, which embedded in acrylic resin. The samples were cut by a sawing machine, and investigated by SEM.
Sixteen weeks after implant placement, the average removal torque of the bicortical group was 24.9 Ncm (range 18 to 30 Ncm, SD 5.0). The average removal torque for the bicortical group was 11.7 Ncm (range 7 to 19.5 Ncm, SD 4.5). There was a highly significant difference (P＜0.001) between the advantage of the bicortical group (Mann-Whitney's U test).
From a qualitative histologic aspect, mature bone was observed around the implants in the cortical region, however, there was little contact in the cancellous region.
It can be concluded that bicortical suppore is From these results, stable and a higher degree of bone-to-metal contact than cortical support.

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The purpose of this study was to investigate the effect of three kinds of storage solutions on the tooth replantation in Japanese monkeys(Macaca fuscata). Examined solutions were 1) organ preservation solution (UW), 2) milk (ML), 3) new solution for tooth preservation (TP), and 4) isotonic sodium chloride solution (DS) as control. Maxillary lateral incisors of 18 animals were extracted and immersed in the storage solutions for 24 hours at 4℃. Root canal treatment was performed during replantation using finger pressure to reposition the tooth.
The replanted teeth and their periodontal tissues were examined histopathologically 2, 4, and 8 weeks after replantation. All replanted teeth retained normal mobility except DS. Histopathologically, the rearrangement of the periodontal ligament around the replanted teeth could be observed at 8 weeks of storage in UW, ML and TP, but root resorption and dent-alveolar ankylosis were observed after storage in DS. Tissues containing fibloblasts were found in a narrow zone in the middle of the periodontal ligament 2 weeks after replantation. The periodontal ligament around the teeth stored in three kinds of solutions revealed no inflammation and that fiber bundles were arranged in a pattern of functional orientation. However, cellular components and fiber arrangement were more numerous and definite in the periodontal ligament stored in UW than those in ML and TP after 4 and 8 weeks. Slight resorption and new formation of cementum were detected on the surface on which numerous cementoblasts existed. These results suggested that examined storage solutions are useful for teeth preservation.

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Application of dental implant has been expanding from single missing cases to completely edentulous cases. However, some researchers pointed out conventional oral rehabilitation modalities, e.g., full denture, could substantially promote the quality of life (QOL). There was a question as to why the implant rehabilitation is necessary in some cases and whether the implants can improve the patient's QOL has not been sufficiently examined. The superiority to conventional complete denture is still unknown. In this study, QOL levels between two groups of subjects, 1) bone-anchored fixed implant denture group (n=6) and 2) conventional complete denture group (n=60), were compared. A questionnaire was developed on the basis of a well-known QOL questionnaire (OHP) and the reliability level was confirmed in each subscale (mean kappa value=0.77) prior to the experiment. This questionnaire consisted of three categories of questions, QOL (12 items), patient's satisfaction (3 items), and oral handicap levels before and after therapy (5 items:food chewing, appearance, speech, comfort, and pain).
The questionnaire was sent to all patients in the two groups after treatment and from the responses, the age, sex, and conditions of the opposing tooth in the two groups were extensively matched. Finally, 6 implants patients (mean age:57.7±11.3 years) and 24 conventional complete denture wearers (mean age: 62.0±5.6 years) were recruited.There was no difference in the general QOL scores between the two groups, while the implant denture group showed a higher satisfaction level with their oral condition and their daily activity than the conventional complete denture group. On the other hand, the oral handicap level before treatment tended to be higher in the implant group than complete denture group. However, the levels were improved by the treatment, so the oral handicap level regarding chewing, appearance, and pain was significantly less in the implant denture group after rehabilitation. Based on these findings, it was concluded that the dental implant patient group in this study suffered more from the oral condition before treatment. However, their satisfaction level with the bone anchored rehabilitation was higher than that of the conventional complete denture group.

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This was a clinico pathological and bone morphometric study on several bone graft materials on the antral floor which was elevated from below. Furthermore, the useful application of the mixture of these materials was discussed in the report. Seventeen patients (5 males, 12 females, age; 39～70 y, mean average 56.8 y) were used in this study. The bone substitutes were 4 individual kinds, Interpore^®, OsteoGen^®, Osteograf^®, and Dembone^® and mixed groups, 1) Interpore group (Interpore^®:OsteoGen^®:Dembone^®=1:1:1), 2) Osteograf group (Osteograf^®:OsteoGen^®:Dembone=3:2:2), and 3) Natural teeth as the control group.
As a result of implantation there was no significant sign of inflammatory reaction around the implants such as gingival redness or puffiness and mobility or percussion sensitivity of the implants.In addition, the pocket depth around the implants was 1 to 2 mm. The success of the sinus lift through implant osteotomy was confirmed at this time. Histopathologically, in the Interpore group, the average was 22.7% bone tissue (new bone 5.5%), 64.5% soft tissue, and 12.8% HA granules, while in the Osteograf group, the average was 13.5% bone tissue (new bone 1.4%), 83.8% soft tissue, and 2.4% HA granules. Therefore, all bone materials were found to maintain adequate bone quantity.

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The release of metal ions in vivo is often accompanied by allergic reactions. Therefore, it is desirable to use the same metal in the oral cavity because of electrochemistry. With this in mind,titanium was recommended, as an implant as well as for a prosthesis. Normally, a prosthesis is made by casting. This study was conducted to investigate the relationship between the spark erosion system and the prosthesis of titanium. The results were as follows:
1.There was no difference between the hardness of the titanium crown made by the spark erosion system and that of the titanium ingot.
2. Through observation, the structure of the titanium crown made by a spark erosion system was the same as the structure of the titanium ingot.
3.The titanium crown made by a spark erosion system was considered to be a clinically viable option.

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