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Biomedical subjects

T P Sperry

Publications and source records attributed to T P Sperry.

12 recordsLinked to original sources
PubMed1993

The limitations of orthodontic treatment.

There is probably nothing in the orthodontist's diagnostic repertoire that will precipitate an adrenaline rush faster than a first examination of a mixed dentition patient who has an obvious skeletal problem. Everyone present in the examination room expects the doctor to manage the problem with some gadget...the same way that produced favorable results for the three playmates in the neighborhood who originated the referral. But intellectually, the clinician knows conventional treatment may not be in this individual's best interest and must intuitively develop a definition of "The Limitation of Orthodontic Treatment."

Adolescent↗
PubMed1989

An evaluation of the relationship between rest position of the mandible and malocclusion.

Rest position of the mandible and integumental change in a control group of Class I occlusions is compared and contrasted with a study group of Class II malocclusion and a study group of Class III malocclusion. Change from centric occlusion to rest position of the mandible was suggestive of simulated correction of the malocclusion and improved facial esthetics.

Cephalometry↗
PubMed1987

Recognition of profile change after simulated orthognathic surgery.

Fifty-one oral and maxillofacial surgeons, 52 orthodontists, 51 orthognathic surgery patients, and 100 lay persons evaluated life-size lateral photographs of two male and two female subjects that had been altered to simulate varying amounts of surgical correction of mandibular retrognathism and prognathism. A horizontal change at pogonion of less than 4 mm was generally not recognized by more than half of the lay groups. The dental groups were more accurate, but even they did not achieve better than 80% recognition until 6 mm of change. Both the dental and lay groups recognized change more easily in the female and the prognathic subjects. When asked which feature appeared changed, dentists generally indicated the chin and lay groups the lips.

Chin↗
PubMed1982

Mandibular movement during autorotation as a result of maxillary impaction surgery.

With increasing use of maxillary surgery to reduce vertical dimension, it would be appropriate to evaluate methods of predicting autorotation of the mandible. Experimental data derived from edentulous patients using metallic implants embedded in occlusal wax rims matched geometrically analyzed clinical data accumulated from twenty-three patients treated by maxillary impaction procedures. The center of rotation of mandibular autorotation during maxillary surgical impaction has been represented in the literature as the center of the condyle. Our evidence with lateral head films taken in centric occlusion supports a different instantaneous center of rotation located within the mastoid region. Modification of prediction tracing techniques by orthodontists and oral surgeons engaged in maxillary surgery could be indicated.

Cephalometry↗
PubMed1982

Physiologic permanent retention following space closure.

Clinical orthodontists recognize that mechanical treatment of excessive space represents a minimum technical challenge. However, retention of this space closure may represent a major challenge to the clinician. With the introduction of direct-bond materials, the patient may benefit from a conservative, noninvasive, fixed retainer. The design described in this article features two main advantages: physiologic action and maximum cleansibility.

Diastema↗
PubMed1977

Differential treatment planning for mandibular prognathism.

The treatment records of thirty-eight cases of mandibular prognathism treated by orthodontics means only (ORTHO) were evaluated. The pretreatment records of twenty cases of mandibular subapical esteotomy (SUB) and twenty cases of mandibular setback (SET) were evaluated for comparison and contrast with the pretreatment ORTHO records and with each other. Dental, skeletal, and soft-tissue parameters in the vertical and horizontal planes of space were recorded. Statistical analysis of means of parameters of the pretreatment records provided documentation of the discriminant variables in each of the following paired groups: ORTHO-SUB, ORTHO-SET, and SUB-SET. Analysis of the data as indicated above led to the following conclusions: 1. Three discriminant groups of mandibular prognathism of various degrees of severity were discernible when comparisons of treatment categories simulating clinical decisions were made. The ORTHO group was distinguished from the SUB group in the horizontal plane and, more strongly, in the vertical plane. The ORTHO group was distinguished from the SET group in the vertical plane and, more strongly, in the horizontal plane. The SUB group was distinguished from the SET group in the horizontal plane. 2. The physiologic developmental status of the patient should be carefully evaluated. 3. Anteroposterior dysplasias should be assessed relative to the cant of the mandibular plane. True denture base discrepancies can be noted relative to the occlusal plane. 4. Documentation of vertical dysplasias should include measurements of craniofacial divergence (SN-MP, FH-MP, and OP-MP). 5. In assessing the profile evaluation of the patient with mandibular prognathism, particular attention should be focused on facial contour angle (FCA), nasolabial angle (NLA), and relative lower lip protrusion (LLP). 6. Any numerical values obtained in the evaluation of the dental, skeletal, or soft-tissue characteristics of mandibular prognathism should be considered only as descriptive, diagnostic guides and not as components of a diagnostic formula.

Alveolar Process↗
PubMed1977

Tooth-size discrepancy in mandibular prognathism.

A Bolton analysis of seventy-eight cases of Angle Class III malocclusion, twenty-six cases of Angle Class I malocclusion, and twenty-six cases of Angle Class II malocclusion was recorded. Frequency of excess mandibular tooth structure, magnitude of the excess, over-all ratios, and anterior segment ratios were computed and analyzed. Two clinical cases were presented to show the advantage of tooth-size harmony in mandibular prognathism. Analysis of the data as presented above suggests the following conclusions: 1. The frequency of mandibular tooth-size excess (over-all ratio) in this sample was greater in cases of mandibular prognathism than in Angle Class I and Angle Class II cases. 2. In those cases with mandibular tooth-size excess, there was a suggestion that the magnitude of the excess was greater in cases of mandibular prognathism than in Angle Class I and Angle Class II cases. 3. A tooth-size discrepancy analysis should be included as one part of the diagnostic records for mandibular prognathism.

Adolescent↗
PubMed1977

The role of dental compensations in the orthodontic treatment of mandibular prognathism.

Thirty-six patients with orthodontically treated mandibular prognathism were recalled for cephalometric and clinical evaluation. A comparison group of 32 non-Class III patients was similarly examined. Analysis of variables associated with the anterior dentition and documentationtion of labial gingival recession and tooth mobility led to the following conclusions concerning the role of dental compensations in the orthodontic treatment of mandibular prognathism. 1. Vertical and horizontal dental compensations were quantitated in the dentition of the study group (pretreatment to postretention). 2. Increased labial gingival recession and increased tooth mobility in functional jaw positions were present in anterior maxillary and mandibular teeth of the study group relative to the comparison group. 3. Proper diagnosis and the establishment of realistic treatment objectives by clinician and patient are necessary to avoid undesirable sequelae and/or undesirable facial esthetics in the treatment of mandibular prognathism.

Humans↗