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Biomedical subjects

R M Ricketts

Publications and source records attributed to R M Ricketts.

At least 37 records · Page 2Linked to original sources
PubMed1976

Bioprogressive therapy as an answer to orthodontic needs. Part II.

From the foregoing discussions, it may be recognized that a new, lighter, and sequential order of force applications is recommended. Accordingly, in order for the clinician to apply the new technique with the intelligence, he must realize that many biologic factors form the fundamental criteria of its application. We have attempted to examine these factors and place them in their appropriate hierarchy of significance. While edgewise was the background, sufficient departure from traditional edgewise therapy has been made to warrant a new label, ""bioprogressive therapy.'' It was so named because of the practice of progressive banding and a planned progression of events in sequential order. Eight steps usually form the frame of reference. Ironically, it can be applied in the very young and in the very old. It is difficult to appreciate these views and practices in the beginning because the method may be difficult to envision on the typodont or as simply a laboratory mechanical exercise due to the fact that cortical bone, growth, and muscle are not present in an artificial medium. In order to fully apply the recommendations of the proponents of this method, mechanical forecasting, physiologic forecasting, and growth forecasting principles are all employed. Even as a simple mechanical regime, however, it rates with or better than any other current multibanded method as a practical and efficient clinical procedure. Size 0.016 by 0.016 inch blue Elgiloy wire is commonly but not exclusively used. Loops or forms are bent in the wire for lighter and more continuous pressures on teeth to be moved. Soldering of auxiliaries has been eliminated, as well as the heat treating of wires. The 0.016 by 0.016 inch to 0.016 by 0.022 inch yellow Elgiloy is used for detailing near the end of treatment. The 0.018 by 0.022 inch is the largest wire employed, and it is used for spanning distances between teeth in the progressive debanding phases. Anchor teeth are stabilized against cortical bone; hence, cortical anchorage. In order to position and control the teeth behind or away from cortical bone or against or away from muscle or to intrude into or extrude away from the bony alveolus, three-plane control is utilized. A limited use of round wire is employed with this technique except for specific isolated conditions in which there is a place for tipping or simple alignment and rotation of teeth. We try to avoid leveling with round wires, for reasons that have been explained. Used as a triple-control technique, the bioprogressive method excels in proper overtreatment and for delivery of anchorage. A continuous arch is broken up into segments so that movements in desired planes of space are not complicated and anchorage can be shifted in favor of the desired move. The technique usually involves orthopedic correction, particularly in the maxilla, when such corrections are needed...

Biomechanical Phenomena↗
PubMed1976

Orientation-sella-nasion or Frankfort horizontal.

The controversy regarding the most appropriate line for cephalometric orientation has been resolved and can be summarized in the following five areas of consideration: 1. Clinical significance. The ability of the clinician to visualize the Frankfort horizontal plane affords him the opportunity for effective clinical communication, which is lacking with sella-nasion. In addition, he is able to demonstrate the orientation of the face, chin, and palate to Frankfort horizontal plane, which is also lacking in the sella-nasion system. 2. Anatomical significance. The direct relationship of the Frankfort horizontal plane with the basic sense organs of sight and hearing displays a relationship to the face. Sella, in contrast, relates to the brain and not the face. 3. Measurement accuracy. Studies performed to test the accuracy of selection of the planes under consideration showed no significant differences when true porion and not the ear rod was used and when experienced technicians performed the tracings. 4. Application in description. If the reference line is to be considered reliable for description, the correlation between the measurements of the maxilla and the mandible to the reference line should be minimal. In a study performed, SNA and SNB displayed a significantly higher correlation than N-Po to FH and N-A to FH. 5. Application in growth forecasting. A study was performed in order to evaluate the application of these lines of orientation to growth forecasting. In every instance the reference frame which utilized the Frankfort horizontal plane was appreciably better than that which utilized sella-nasion.

Cephalometry↗
PubMed1976

New perspectives on orientation and their benefits to clinical orthodontics--part II.

As composites were compared from the frontal and lateral, the organization tended to point to orientation of growth of cavities in the face from the divisions of the fifth nerve. Three-dimensional constructed capsules of the orbital, nasal and oral cavities may be reduced to the inputs from the entrance of these nerves into their appointed functional matrices. These orientations were found to be so useful and beneficial that they have been adopted for computer functions. They have also been found fruitful for prediction.

Adolescent↗
PubMed1975

Arcial growth with metallic implants in mandibular growth prediction.

The present investigation was undertaken to determine whether the Ricketts theory of arcial growth of the mandible can be put to practical use by the clinician to predict mandibular morphology. Eight subjects (six girls and two boys) were selected from the earliest implant samples at the Orthodontic Department of Emory University School of Dentistry. The initial cephalograms were coded and sent to Ricketts, and a 6-year manual growth forecast using the arcial method was requested. The final cephalograms were traced and compared. The three tracings (initial, prediction, and final) were superimposed over the metallic implants and presented on a case-by-case basis. The forecasts, in form, were clinically acceptable in five of the eight cases. In two of the cases (girls) (Cases 2 and 4) a hand-wrist radiograph to determine skeletal age would have improved their accuracy. The forecast in Case 2 was not acceptable. In view of our results in this small sample, the arcial method appears valid for prediction of amndibular growth; however, hand-wrist radiographs will improve the accuracy of short-range predictions of the amount of growth expected. For this reason, the orthodontist should constantly monitor his patients, watching for each individual to assert himself.

Adolescent↗
PubMed1975

New perspectives on orientation and their benefits to clinical orthodontics - part I.

The historical development of cranial reference lines, basic to cephalometric orientation, was discussed. The evolution to, away from, and back again to the Frankfort horizontal plane for descriptive and communicative purposes as benefits to the clinical orthodontist was explained. Objectives were set forth as a basis for selecting the most appropriate method in orienting the headplate for measurement and assessment. The major functions of cephalometrics were pointed out to be its use for description or classification of the face together with the malocclusion and for superimpositioning for longitudinal comparison. Each of these purposes calls for particular requirements pointing to the need for combinations of planes and multisuperimposing. The statistical findings via a computer pointed to the use of the Frankfort plane as the most desirable basic reference for descriptive reasons. Composites also suggested good order from Frankfort horizontal when serial tracings were compared. It was emphasized that true porion was used, not the ear rod of the cephalometer. For growth analysis the basion-nasion plane was shown to be longitudinally of superior value for chin behavior.

Adolescent↗