Field Of Prosthodontics Research Articles

健康科学を基盤とした歯科補綴学の構築―咬合・咀嚼が創る健康長寿の実現へ向けて―

Prosthodontics is a practical science based on life sciences and health sciences, and takes a role to contribute to the improvement of people's health and welfare. It is true the main field of prosthodontics and/or prosthodontic treatments is oral rehabilitation including recoveries of morphological defects and the functional disability caused by teeth loss. From this point of view, I am sure that the ultimate target of prosthodontics and/or prosthodontic treatments is maintenance and improvement of patient's QOL. To achieve this purpose, I think research, education, and clinical practice to be inseparable and integral in prosthodontics. This ensures that prosthodontics become more academic which can contribute to the society more greatly. Advertisement disclosure of "Prosthodontic Specialist certified by Japan Prosthodontic Society" is our earnest wish. The specialist system is regarded to be effective for the improvement of the medical treatment level, the information provision to the patient, and the promotion of cooperation hospital and clinic. On the other hand, the high quality treatments are severely requested and the specialists are strictly evaluated by the many people more than before. We have to be aware of our responsibility as Prosthodontic Specialists. In addition, Japan Prosthodontic Society is a corporate judicial person, and there is obligation and a responsibility that transmit necessary information to the society certainly and promptly, and present various proposals based on EBM as the opinion leader. Concretely, it is necessary to promote basic researches as well as clinical researches on prosthodontic treatments, and to examine the improvement of educational methods of prosthodontics. Let's reconfirm the purpose of our Society written in the article of incorporation and make an effort to achieve this purpose!

Skills Improvement Seminar for Submitting Articles to the Prosthodontic Research & Practice Journal

In the scientific meetings of the Japan Prosthodontic Society, many high-level research presentations are given, and yet a large proportion of the presentations have not been published. Since 2002, the Japan Prosthodontic Society has published PRP (Prosthodontic Research & Practice), which is the official English journal of the Society, to introduce scientific data of research in the field of prosthodontics internationally. PRP will be published quarterly from 2006. The editorial committee of the Japan Prosthodontic Society tries to give advice to authors, and to publish the prepublication paper in the PRP journal not as a rejection but as a correction. In order to give members of the Japan Prosthodontic Society a better understanding of the PRP journal, we held a Skills Improvement Seminar for Submitting Articles to the PRP at the 114th scientific meeting (Niigata) and the local branch scientific meetings. This paper summarizes the first half of the seminar and describes the editing work of PRP.

Rigid and resilient investing materials - Expected movement of teeth in fabrication of complete dentures: An invitro study

Dentistry is going through a series of radical and important changes. So, has the field of Prosthodontics seen an introduction of numerous techniques being offered for the processing of dentures with acrylic resin according to their investing method. The investing could be done by Compression Molding Technique or Fluid Resin Technique. Compression Molding Technique normally requires gypsum mould which is rigid. The newer investing material silicone, when used for investing waxed up dentures reproduces finer details and better polish surface of acrylic resin dentures. Silicone being resilient movement of teeth during processing could be expected. The purpose of this study was to compare silicone and gypsum as a coring material for flasking. Also the movement of teeth in 3 directions i.e. medio-lateral, anterior - posterior and vertical directions were investigated and evaluated.

Systematic review of 10 years of systematic reviews in prosthodontics: Nico H. J. Creugers, Cees M. Kreulen. Int J Prosthodont 2003;16:123-127

Purpose The objective was to make an inventory of systematic reviews in the field of prosthodontics and to assess the strength of evidence yielded by these studies. Materials and methods The literature was searched using MEDLINE (keywords “dental” in subset combined with “meta-analysis” in publication type, and “dental” in subset combined with “systematic review”). Reviews related to prosthodontics were selected by hand. Analogies between the reviewing processes were assessed, and the quality was described. Results There were 138 articles qualifying as either systematic reviews or meta-analyses. Of these, 13 reported pooled data on prosthodontic subjects. Two pairs of reviews were identified as dealing with comparable items; the others described all different subjects. In one pair, the studies reviewed the survival of conventional fixed partial dentures (FPD); the other pair was on single-tooth implants. The pooled results within each pair were almost equal. For the FPD reviews, 65% of the unity of studies was included in both reviews. For the single-tooth implants, 29% of the potentially useful studies were included in both reviews. The data pooling processes showed the same pattern. One large study included in both reviews explained a large part of the similarity of the combined survivals of FPDs. For the single-tooth implant reviews, the largest common study explained 20% of the similarity. Conclusion Although there were methodologic differences between the paired reviews, they produced similar results. The outcomes of the evaluated reviews may be used as prognostic data; however, they cannot be used for direct comparison of treatments.

PROSTHODONTICS: ACHIEVING QUALITY ESTHETIC DENTISTRY AND INTEGRATED COMPREHENSIVE CARE

Prosthodontics is the dental specialty responsible for diagnosis, rehabilitation and maintenance of patients with complex clinical conditions involving missing or deficient teeth and/or craniofacial tissues. The essence of the specialty is expert treatment planning. In recent years, new approaches and technology have been introduced as a result of research performed in universities and by industry. The field of prosthodontics continues to evolve owing to a better understanding of the biology of the oral cavity and the introduction of new techniques and improved biomaterials. Improvements in periodontal and oral surgical techniques, implant procedures and materials, esthetic restorative materials, and jaw tracking recorders and articulators have led to enhanced functional and esthetic oral and maxillofacial prostheses. The complexities of today's technical and clinical procedures and the higher expectations for more esthetically pleasing dentistry by the general patient population have placed a premium on teamwork involving general dentists, specialists and dental technicians.

ＣＡＤによる菌冠形態設計法の研究

Recently, various approaches have been conducted to apply CAD/CAM into the field of prosthodontics. Successive studies on a computer-aided approach to construction of coronal restoration were performed at our Dept. since 1984.The purpose of this study is to explain our method of measuring the prepared tooth placing the master pattern and modifying it according to an individual morphology of each tooth by CAD.The procedures can be successfully performed in the following ways by means of 3-D Measurement-Milling Apparatus (Type A-1) developed by our Dept.1. The application of the polar coordinates measurement of the master pattern makes it possible to display the occlusal surface and contact relationships between maxillary and mandibular teeth.2. The cervical margin is measured in a rate of 50μm with each interval of 1mm in vertical direction utilizing the cyrindrical coordinate that determines azimuth with 0.5 degrees.3. Finally, the occlusal surface of the master pattern and marginal line are connected by Hermite Curve, then the design of external contour is completed by CAD.

レーザードップラー血流計による歯肉，口蓋粘膜および皮膚面の血流測定に関する補綴学的検討

The purpose of this study is to evaluate the prosthodontic usefulness of laser doppler flowmetric (LDF) measurement of the blood flows in gingival and palatal mucosae and skins overlying the masseter muscle and temporomandibular joint.High reproducibility was obtained in the LDF measurement of the blood flows at these sites.The gingival mucosal blood flow (GBF) was increased by application of a cold or hot stimulus and decreased by clenching. It was also decreased by experimentally produced gingivitis. GBF was found to be correlated to the volume of gingival groove fluid which was measured simultaneously.The palatal mucosal blood flow (PBF) was increased transiently by application of a cold or hot stimulus and decreased by impression. It was also decreased by attachment of an experimental palatal plate.The skin blood flow over the masseter muscle (MBF) was increased by clenching. No significant change was observed in MBF by chewing of gum. The skin blood flow over the temporomandibular joint (TBF) underwent no change by irradiation of soft laser beam or application of a topical antiinflammatory agent. Both MBF and TBF were decreased by pulsing from a myomonitor.These results suggested that LDF is useful in the field of prosthodontics as a method for measurement of blood flows.

Etched castings as an adjunct to mouth preparation for removable partial dentures

Electrochemically etched nonprecious metal castings have been bonded to etched enamel for use in mouth preparation procedures for removable partial denture placement. The castings have been in service and subject to loading by the dentures for 26 to 42 months. To date, bond strengths have been sufficient to support function of both castings and removable partial dentures clinically. None of the castings has failed in its bond. Evidence that the technique may be a valuable adjunct is building in the field of prosthodontics. Use may be far reaching as dentists apply the concept to a wide variety of patient requirements in dental treatment. As more commercial dental laboratories acquire the capability to etch metals, cost should be minimized. Application is not time-consuming. Some steps are technique-sensitive, however, and short cuts are not well tolerated. This is especially true of cementation procedures where moisture or contamination of the field may lead to failure of the bond. It should be noted that each nonprecious metal is different from other metals in its composition, and therefore, results and techniques reported in this study can only be cited for the metal used. In addition, the acid used for etching one alloy may not be effective on another alloy. Finally, it is important that all castings be checked under a binocular microscope to ensure that proper etching did occur. Underetching and overetching both lead to a weakened bond and potential failure.

Prosthodontics—Past, present, and future

1. The geographic areas served by licensed dental mechanics will increase in number and size in the future. 2. There will be increasing difficulties in supplying dental graduates of a high caliber from our faculties of dentistry to serve adequately in the field of prosthodontics. 3. More graduate (postdoctoral) programs will be needed to train dentists to treat difficult prosthetic patients. The need for prosthetic services is still with us and will continue to grow. Only with progressive thought and aggressive action can organized prosthodontics go forward to meet its challenges. A battle is not won on defense alone, for such has been the game plan to date. Currently, dentists have a reasonable way to deliver an important health service to the population at large. However, only with a rapid advancement in the concept of delivery of total prosthodontic care can the best interests of the public be maintained. Finally, the highest standards of practice and ethics must be the guiding principles to any future changes in the delivery of prosthodontic services to the public.

Phase relations in the CaO-P 2 O 5 -H 2 O system from 300 degrees to 600 degrees C at 2 kb H 2 O pressure

Reduced mouth opening or microstomia is a frequently encountered condition in the field of prosthodontics. Microstomia is a challenge for prosthodontics right from impression making till the insertion of the prosthesis. Making impressions in patients with microstomia is often cumbersome for both patient and operator. Standard impression procedures are not of any help due to limited mouth opening, so the modification of standard impression procedure is often necessary while treating such patients. Modification in denture prosthesis in the form of split denture, flexible denture, hinged denture, spring denture etc is needed to fulfil patients’ demands. The present case displays the treatment of a patient with microstomia using modified impression tray design and maxillary split denture.

The principles of visual perception and their clinical application to denture esthetics

The perceptual principles can free dentists from the confusion existing in the field of dental esthetics and enable them to confidently approach the task of enhancing their patients' appearance. Principles may be applied to all and they eliminate the personal attributes of talent and the need for learning specific formulas for achieving an esthetic result. “The determination of the form principles in a specific example of design means, in a sense, the elimination of the personal element. With this element removed the residue represents merely the planning knowledge possessed by the artist. ... Invariably the higher or more perfect the art, the richer is the remainder when the personal element is removed.” 17 The eye is a perfectly competent evaluator and errors will become obvious if a long contemplative look is taken at the tooth arrangement during the try-in appointment. A real need for a very detailed, almost histologic approach to dental esthetics exists. Indeed, the perceptive principles may be regarded as the cellular elements of which the tissue of denture esthetics is composed. As familiarity with the principles increases, so does proficiency in their application. With experience, the basic shape and characteristic of the dental tooth arrangement can be visualized even before a single tooth is placed in wax. All that remains is a detailed examination at try-in to look for minor perceptive conflicts, and this too becomes less of a task with the training of the eye to really see. The field of dental esthetics is of critical importance to the well-being of patients, and one of dentistry's greatest challenges is to completely eliminate the delivery of static, poorly planned, clumsily executed dentures. This challenge is each individual dentist's responsibility and cannot be subcontracted. The laboratory technician is a valuable ally, but he has no decision-making role in the area of denture esthetics. Fisher 18 has best stated the objectives that must be achieved in denture esthetics. In his words, “It is the purpose of those who have labored diligently and long in the pursuit of a more workable basic principle in esthetics to encourage all of those whose tasks take them into the field of prosthodontics to consider the opportunity to lift the patient out of the category of a geometric figure and restore to him his true quality of a living and breathing man or woman, with an individual personality and either the dignity of his years or the freshness of his youth.” This is the proper note on which to close, or perhaps to begin.

Implant dentures: Prosthodontic—Unfavorable

In my discussion of the unfavorable prosthodontic aspects of implant dentures, I have avoided reference to the surgical techniques and consequences which are being discussed by others. I have only touched upon what I believe to be disadvantages or deficiencies of the procedures. The most serious disadvantage is that the procedure cannot be used for those who need it most. It is not advised for aged, infirm, or unhealthy people. Soft tissue-borne dentures can be and are made for these people, and if they are carefully and precisely constructed, these dentures do provide teeth which are comfortable and usable. Judging by the implant dentures I have seen and by many illustrations in books and periodicals, insufficient attention has been paid to jaw relations and occlusion. These are phases of construction techniques that could be corrected easily, however, if more attention was paid to them. The illustrations I have seen of upper implant dentures indicate that too little consideration has been given to phonetics. The shape of the maxillae and mandible is altered by resorption. This resorption may occur under soft tissue-borne dentures and implant dentures alike. It is more disastrous when it occurs under implant dentures. The expense of treatment of edentulous patients by implant dentures makes the procedure unavailable to many people who might be benefited by it. The time involved in treatment of edentulous patients by implant dentures makes the procedure unavailable to most edentulous patients because there are not enough dentists to provide the service, even if all other unfavorable considerations were eliminated. This discussion is not intended to discourage sincere workers from further experimentation in this field of prosthodontics. Instead, I hope that it may point the way to an improvement of implant denture service.

A Philosophy of Patient Education

Failure to properly educate the patient must be classed as one of the main causes for many of the difficulties we encounter in denture construction. For this reason, it is imperative that we give serious thought to a carefully planned educational program that will eliminate the possibility of misunderstanding. The first requirement is to cultivate the ability to see the entire problem from the patient’s point of view. Patients need sympathetic understanding every bit as much as they need technical proficiency. This suggests a broader viewpoint which goes far beyond impressions, waxes, teeth and articulators. Several psychological truths regarding human behavior and motivation have been discussed as valuable adjuncts in planning this program of enlightment. They have been explained in principle and some suggestions have been made as to how they might be put to practical use. It has not been our intent to put words into the mouths of those who read this discussion, but rather to stimulate serious thought. We have attempted to emphasize the “why,” leaving the “how” to the ingenuity of those who truly understand the use of these basic principles. When a program of patient education is based upon a human approach plus a good understanding of certain basic psychological truths, the field of prosthodontics becomes one of the most fascinating and rewarding lines of endeavor that can be found in the entire practice of dentistry.