User:Jack Frush/sandbox

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John P. Frush D.D.S. History of Professional Activity Graduated from the School of Dentistry, University of Southern California. During WWII Dr. Frush entered the service and became chief of in-patient oral surgery at the Marine Hospital in San Francisco, having just come from the same position for Lockheed Corporation in Burbank, CA. In the middle 50's, Dr. Frush was appointed to the post-graduate staff in Prosthodontics at USC. Covered in six articles for the Journal of Prosthetic Dentistry, he established the importance of the color changes in individual teeth and the vital factors of the patient's sex, physical personality and age (SPA factors) to the esthetic composition in complete dentures. These procedures were also adopted by the post-graduate section, University of California. For the past 30 years Dr. Frush has given full Jaime to his denture practice and the many activities related to that subject. Technical Contributions He established the Swissedent Foundation in 1953 as the research division of the Swissedent Corporation. In this clinical research environment, he developed and patented, for denture teeth, the macroscopic color changes which occur in natural anterior teeth as a result of progressive incisal wear pigmental penetration of the resultant facial cracks in the enamel of the central incisor teeth. Artificial teeth were then made in Switzerland, which followed this natural phenomenon in combination with the enduring bluish incisal edge of at he lateral incisors. This became known as a physiologic color combination derived from the study of natural anterior teeth. This phenomenon is still reproduced in their top-of-the-line artificial teeth by the Swiss. Dr. Frush also developed the Alameter, Papillameter, Rim Former, and the Esthetic Control Base for determining the optimum mold for the patient as well as the independent position of the anterior teeth according to the SPA factors. His design of the ball bearing bite recorder for pre-operative condylar adjustments and intra oral tracings plus Centrimatic teeth for non-interceptive occlusion came along later when he presented the Myostatic concept of lower denture extensions to enhance optimal functional stability. In 1970 he introduced a multi-colloid impression system for the edentulous mouth which employs two hydrophilic elastomers of different viscosities in a single entry procedure. Well accepted and in widespread general use, this impression system is both more economical and patient friendly, and satisfies all the classic requirements of complete denture impressions. Recently he has developed a simple pressure applicator for the elimination of air bubbles on the teeth and investing structures when making multi-colloid impressions of the partial dentate mouth. This procedure usually pre-empts the need for custom trays, especially in difficult situations. Literature As co-author with Dr. R. Fisher, he produced a total of six articles in the Journal of Prosthetic Dentistry on the Dentogenic Concept of Esthetics and an article in the Illinois Dental Journal on Linear Occlusion and Non-interceptive Inter-Arch Contacts. He also wrote "Dynesthetics Illustrated", a technical description of procedures in creating esthetic compositions in the six anterior artificial teeth based upon the patient's SPA factors. Instructional In addition to his teaching activities at the Swissedent Foundation and post-graduate section at U.S.C., Dr. Frush has been an essayist at the Annual Meetings of the California Dental Association, Hinman Clinic, Dallas Mid-Winter Meeting, Chicago Dental Society, and the Academy of Denture Prosthetics plus many others including the American Dental Association of Europe in Amsterdam. In the early seventies, he lectured at the University of Zurich and the Ecole Dental, University of Paris. His itinerary also included post-graduate courses at some 14 schools in the U.S. For the past 25 years, Dr. Frush has concentrated on upgrading the standards of treatment by the general practitioner for the edentulous patient by creating new products and procedures which put the goal of excellence in reach and within the framework of practical dental practice economics. His efforts have included successful simplification and clinical improvements of impressions, jaw relations and occlusion: the three responsibilities of the professional, and the most controversial in denture procedure. Synopsis of One Day Lecture on Complete Dentures The success of dentures in the eyes of the operator is measured by the number of adjustments needed. Their success occurs when the patient ceases to complain and / or return for help. This is the so-called "break-in" period, and from the dentist's perspective, the shorter it is, the better. When the patient stops complaining, and intraoral evaluation of balanced occlusion, suction in the lower, protrusive balance, centric position or anything else seems superfluous to the operator, Obviously the patient is satisfied with things as they are and has adjusted physically and psychologically to completed dentures. So, why recall the patient for a tune-up? Factually, denture success depends mostly on the pain and emotional thresholds of the patient. People don't "break-in" dentures, dentures break-in people and most patients just learn to live with loose lowers and discomfort. This is not necessary. Most of the element causing pain, discomfort and the need for continued adjustments can be anticipated and removed within the framework of our impressions, our jaw relations, the selection of occlusion and our control of inter arch contacts. These pre-emptive methods will be discussed and visually demonstrated along with a review of the psychological factors involved in complete denture esthetics.

'''Linear Occlusion By Dr. John P. Frush Bold text''' Linear occlusion is an entirely new occlusal design. It is intriguing because of its simplicity and its remarkable success in practical usage. By incorporating an extremely effective chewing mechanism with linear stability in the occlusion, an entirely new combination of prosthetic advantages is achieved. Linear occlusion definitely provides a stabilizing effect on the denture bases during function. Heretofore, occlusion for full dentures has been limited to three-dimensional (cusp) occlusion and two-dimensional (flat plane) occlusion. When the combined points of contact on the occluding surface form a flat plane, the tooth is two-dimensional. When any portion of the occluding surface is above another portion of the occluding surface, the tooth is three-dimensional All of the posterior tooth designs which have been available fall into either one of these categories. Two-Dimensional: Fench, Halls inverted Cusp, Myerson & Sears, Tru-Byte Rational, Univac Bio-Mechanical. Three-Dimensional: Criterion, Myerson's Synchronized, Pilkington¬Turner. Tru-Byte Dentron, Tru-Byte Fournet, Tru-Byte Functional, Tru-Byte New Hue Diatoric, Tru-Byte 20 Degree, Tru-Byte 30 Degree, Tru-Byte 33 Degree. Univac Nuform, Univac NIC, Verident NIC. Linear occlusion allows us to complete the geometric classification of occlusion by providing a one-dimensional occlusal design. As such, it provides the practitioner with a valuable new tool to cope with prosthetic problems. Geometric classification of occlusion is not a pure geometric interpretation of the entire bilateral occluding surfaces of posterior teeth. A geometric classification of occlusion describes the dimensional contact (one, two or three dimensional) between the occluding surfaces of any two opposing teeth. 1) Cusp Occlusion In cusp occlusion the contact between the opposing surfaces of any two teeth occurs in three dimensions. These dimensions are the width of the occluding surface, the length of the occluding surface, and the depth of the occluding surface. These dimensions are the width of the occluding surface and the length of the occluding surface. 3) Linear occlusion Linear occlusion is a one- dimensional contact between two opposing posterior teeth. The contact occurs only in one dimension which is the length of the contacting blade (not surface). This blade, being always in the form of a straight line, geometrically constitutes "length" in occlusal contact without either "width" or "depth" of occlusal contacts. There is ample clinical evidence that one-dimensional occlusion has certain advantages over either two or three-dimensional occlusion because of the geometric simplicity of the occlusal contact. The reduction in the amount of occluding surface accomplished by one-dimensional occlusion likewise reduces the potential occlusal deflections which may occur with broader contacting surfaces. Directions of Force Directions of force developed in any kind of surface contact between opposing posterior teeth (two or three-dimensional occlusion) necessarily change with any alteration in the relationship of these opposing occlusal surfaces, such as with lateral excursion of the mandible. Directions of force in three-dimensional occlusion can be determined by observing the slopes of the contacting inclined surfaces in Diagram A. However, if the relationship of there contacting surfaces suddenly changes, through lateral excursion of the mandible, the directions of force also change, as in Diagram B. directions of force are vertical to the flat surface opposing the blade, as in Diagram A. Any change in the position of the linear contact against the upper surface, as in a lateral excursion of the mandible, would not appreciably change the direction of force, which still remains essentially vertical Diagram B. In the opposite excursion of the mandible, the blade still contacts a flat surface and the direction of force remains essentially vertical, Diagram C. Likewise, in two-dimensional occlusion, the directions of force can be determined by observing the angle of the surface contact. Of course, in two-dimensional occlusion the surface contact is presumably occurring at a flat or level angle, Diagram A. However, the slightest change in relationship of these opposing surfaces, such as a lateral excursion of the mandible, produces a bilateral imbalance with an attendant tipping of the denture base in relationship to its original position on the tissue, Diagram B. Whereas, in linear occlusion the C. rno Converpcn. To a patient, chewing efficiency is apparently first related to the ease with which he can penetrate and cut the bolus of food. Next, chewing efficiency to a patient is related to the comminution of the bolus of food. Next, chewing efficiency to a patient is related to the comminution of the bolus after it is penetrated and cut. Many methods of introducing easier penetrating and cutting power to the occlusion have been attempted in the form of cutter bars which occur in various shapes. If one studies the various types of cutter bars it becomes apparent that the simplicity of a straight line (one-dimensional) occlusal contact is not maintained. Therefore, it is doubted that the efficiency of a simple blade contact in the occlusion has been properly documented. One of the prerogatives every dentist has is to make his own comparison and personally document the practical difference between linear occlusion, whichever he has been using. The best way to do this is on an existing set of dentures which are at the present time less than satisfactory. The attached procedure should be followed. The one-dimensional; occlusion at present in use (about 20,000 cases) includes a crushing surface lingual to the linear contact as shown in the diagram below: This crushing surface, in order to maintain true linear contact between the occluding surfaces, never touches. Carbon paper will determine this when the dentures are seated at the delivery appointment. However, it can be seen that the person who sets up the teeth and finishes the dentures has control over the distance between the crushing surfaces lingual to the blade. As in a ball mill, or any crushing mechanism, the proximity of the crushing surfaces determines the fineness of the separated particles. For instance, in the ball mill where gypsum is crushed by stainless steel balls, the size of the particles is determined by adjusting the proximity of the stainless steel balls. It is interesting to note that in the finest of particles the balls never quite touch. If one studies the diagram below, it becomes apparent that the space between the crushing surfaces varies greatly from the extreme lingual (L) to the blade contact (B). Apparently, from clinical experience, the separation of the crushing surfaces at "L" should be no more than a millimeter (.040"). ....,7 improvement in comfort, stability and chewing as a result of one-dimensional occlusion. This seems sufficient to indicate an advantage over two-dimensional and three-dimensional occlusion. A very important aspect of this innovation is that it seems to provide the following: 1)	Reduction of needless problems due to complexities of occlusal contacts and resultant deflections. 2)	Simplification of prosthodontic procedure. 3)	Reduced post-insertion adjustments with an attendant time-saving factor in both laboratory and operatory. 4) A general increase in chewing efficiency, comfort and stability of full dentures. Denture Techniques Whatever denture techniques or procedures being use can be continued. For instance, impressions and relationships, the mounting and re-mounting of the dentures, etc, can be done according to present practice. When the dentures are constructed with flat plane or cusp teeth, any kind of articulator can be used. However, with linear occlusion there is a definite requirement. Any articulator with an incisal guide pin, a flat incisal guide plate, and an adjustable condyle inclination can be used. The Hanau articulator is ideal for this, the exception being the extremely old Hanau with the cup type of incisal guidance. Centrimatic articulators are recommended because they already have a fixed 12 degree condylar inclination and a flat incisal guide plate. Laboratory Procedures When one-dimensional occlusion is used: 1) The lower anterior teeth may be set with as much horizontal overlap as necessary, but the vertical overlap should be zero. This is a requirement of linear occlusion. To have any interference in right or left lateral or protrusive (cusp rise) defeats the bilateral line contact necessary between the upper and lower dentures at all times. Protrusive balance is desirable. 2)	All the lower teeth will be set on a flat occlusal plane. The anterior level of the occlusal plane will be the lower anterior teeth, and the posterior level of the occlusal plane will be approximately at the top of the retromolar pads. 3)	Technicians should set the lower posteriors with the buccal surfaces nearly straight up and down. This will bring the linguals of the first and second molars almost as high as the buccal blade on these teeth. The linguals of the bicuspids will not be as high because of the basic design. The bicuspids were designed to cut more than to crush; therefore, it is not expected that the occlusal surface lingual to the blade on these teeth will be used as much for crushing as will the first and second molars. 4)	The upper posteriors are set with the occlusal surfaces level and with the central fossa of the upper teeth against the blade of the lower posterior teeth. If the linguals of the lower molars and of the upper molars touch when the upper posteriors are set, it is okay. Note: The separation between the linguals of the upper and lower posterior teeth is eventually achieved at the expense of the lower posteriors. After the teeth are completely waxed, the occlusal surface lingual the blade of the lower posteriors is ground for proper clearance. 5) Following are the salient features of a one-dimensional occlusion in the set-up: 1.	All the lower teeth on a flat occlusal plane; this plane extending from the lower anteriors towards the top of the retromolar pads. 2.	The combined buccal blades of the lower posterior teeth should form a perfect straight blade. This blade should be perfectly straight to support one-dimensional contact against the opposing occlusion. 3.	The crushing table lingual to the buccal blade on the lowers should be adjusted to create an inter-occlusal crushing space of approximately one millimeter. 4.	Zero vertical overlap between the anterior teeth. It should be noted here that any interference in a protrusive movement requires a change in vertical to avoid this interference. A forced change in vertical dimension in this instance produces the same kind of a deflection of the denture base on the mucosa as would a cusp rise in lateral excursion of the mandible. 6) Cusp rise is removed from the upper occlusion before the dentures are delivered to the patient. This is why a flat incisal guide plate must be used on the articulator. It is best to accomplish this after the dentures are deflasked and remounted on the articulator. If the laboratory (or the dentist) does not usually re-mount the dentures before delivering them to the dentist, the cusp rise would be removed in the wax-up. The laboratory procedure for removing cusp rise on the articulator is as follows: 1.	Set the incisal guidance at zero degrees and the condylar inclination at 12 degrees. (The Centrimatic articulator automatically has these features;) 2.	Adjust the upper occlusion until the pin touches in centric. 3.	Remove any contact marks which appear on the crushing table of the lower posteriors. Never grind the lower blade itself. 4.	Run the articulator through right and left lateral. Balance is automatically achieved by grinding away the interferences, revealed by the carbon paper on the upper teeth, which lift the pin off the incisal guidance plate. These must be removed to eliminate cusp rise. 5.	Continue to relieve the upper occlusion through right and left lateral until the pin maintains contact with the incisal guide plate through all excursions. This automatically balances the occlusion! 6.	If necessary, remove any interferences in protrusive by grinding the lower anteriors. When switching from flat plane or cusp occlusion to linear occlusion, the set-up is the same as for a set-up of linear occlusion on new dentures. Note: If the anterior teeth are locked or touch in centric after the dentures are mounted on the articulator, the technician should arbitrarily open the articulator to relieve this anterior interference. This arbitrary opening is possible only with linear occlusion. It should not be done with either cusp or flat plane teeth because neither of these can accommodate the slight change in centric occlusion which is affected by such a procedure. Use the following technique for switching posteriors: 1)	Carefully position the occlusion of the dentures into centric contact. Do not use a wax or plaster relationship for this purpose. Sticky was the teeth together preparatory for mounting. 2)	Mount the dentures with the occlusal plane sloping up and back. If it is customary to use a face bow for mounting dentures, this is even better. 3)	Set the teeth and cure. Either cold cure or heat cure is satisfactory. In the event cold cure is used, the articulator should be opened slightly to accommodate for the shrinkage which always occurs. General Considerations The author of this memorandum on technique has personally taught more than 500 dental technicians the use of one-dimensional occlusion in dentures. The greatest obstruction to learning the proper application of one-dimensional occlusion by the technician is habit. The habits developed in full denture work by a good technician over a period of years are necessarily associated with either flat plane teeth or cusp teeth. With these two types of occlusion, there has been little need for precision placement of the individual teeth. For instance, the technician learns to set teeth very rapidly and to rationalize the set-up to this speed. If a lower molar is placed buccally or lingually a millimeter in relationship to the approximating teeth, it is not necessary to correct. Not so with linear occlusion. The very simplicity of this occlusion sometimes defeats precision performance by the technician,. In looking at the occlusion, he over-simplifies it and fails to realize the geometric significance of a bilateral straight line contact in the occlusion. If one lower posterior is buccal or lingual even a half-millimeter to the intended straight line, a second dimension is immediately incorporated into the occlusion. The slightest deviation from one-dimensional occlusion can cause post insertion problems of soreness or looseness which the operator should immediately investigate and correct in the occlusion. Linear Contact There is no excuse for a laboratory technician not to understand why linear contact is so important and not to implement it in the set-up. However, the final control of this must be in the hands of the operator. This is ordinarily done when the finished dentures are delivered from the laboratory for insertion in the patient's mouth. The operator should take a lead pencil and mark the edge of the blade to check its accuracy; then, with carbon paper, the operator should be sure there is no other contact than the

He had several revolutionary ideas. One was setting up the artificial teeth in a denture to reflect the sex, personality and age of the patient so the denture looked like natural, healthy, age appropriate teeth. He started a company called Swissedent in 1956His concept, called Dynesthetics, was way ahead of its time. He even had to work with artificial tooth companies to develop more natural looking teeth to implement his ideas. Dr. Frush taught Dynesthetics for many years both in the US and abroad, to audiences numbering in the hundreds. He had a unique idea that the dentist and laboratory technicians should come together to his lectures, this was unheard of in the 50's. He felt that since they needed each other to create a great denture that is was correct for them to learn the Swissedent technic together.

His other great idea was developing an impression technique for edentulous patients. Traditional impression techniques used for patients with teeth did not work well for edentulous patients. His Accu-Dent system used two alginates- one heavy bodied and one light bodied- together with specially designed impression trays to take a "final impression" in a single 15 minute appointment. To this day, dentists routinely take two appointments and up to 90 minutes to fabricate a suitable final impression for an edentulous patient.