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Biomedical subjects

P Rygh

Publications and source records attributed to P Rygh.

35 records · Page 2Linked to original sources
PubMed1990

[New treatment modalities for patients with cleft lip, jaw and palate].

Cleft lip/palate patients are reported at birth to a national register and are referred to one of the cleft palate teams in Oslo or Bergen. The teams coordinate the active treatment periods by plastic surgery, orthodontics/jaw orthopedics, logopedics, otology, pediatrics, psychology and orthognatic surgery. Presurgical orthopedics is performed early after birth in some total clefts with very asymmetric jaw segments. Lip is closed at 3 months, hard and soft palate at 1 1/2 years. Only a few cases now need early protraction of the upper jaw due to growth restraint. Many need orthodontic repositioning of the jaw segments and establishment of good occlusion. Bone from the ileac crest is grafted to the cleft prior to eruption of the canine. This permits normal development of the alveolar bone and eruption or, if the lateral is missing, orthodontic mesialization of the canine, excluding prosthetic replacement.

Adolescent↗
PubMed1987

The effect of maxillary protraction on front occlusion and facial morphology.

The intention of this work was to study the dentoalveolar and basal jaw changes in a group of children (aged 5-10 years) with nonforced anterior crossbite treated with maxillary protraction from a face mask and to compare the changes with those found in a control group with normal dentoalveolar and basal maxillomandibular relationship. The data were obtained from lateral cephalograms of 22 children taken before treatment, after a treatment period of 3-12 months, and after an observation period of 6-48 months. A group of children (n = 40) with normal maxillomandibular relationship served as controls. During treatment the mandibular prognathism was reduced, and a positive overjet was established in 18 children. The changes during the observation period were generally comparable to those found in the control group, and thus indicated a very small relapse tendency. The posttreatment comparison of the groups showed fewer significant differences than before treatment, indicating that the treatment had a normalizing effect not only on the negative overjet but also on the general face morphology.

Activator Appliances↗
PubMed1986

Activation of the vascular system: a main mediator of periodontal fiber remodeling in orthodontic tooth movement.

The behavior and role of blood vessels and blood-borne cells in the process of the remodeling of the periodontal ligament (PDL) incident to experimental tooth movement was studied in rats. Particular interest was focused on areas of tension and of pressure with frontal bone resorption but without overt hyalinization. An increase of vascular activity occurred in the above mentioned situations. Extensive breakdown of collagen was observed in pressure areas with frontal resorption and in areas of tension concomitant with vascular invasion. Two patterns of fiber and bone remodeling were seen in areas of tension: intense vascular activity within the periodontal membrane and intense vascular activity inside the alveolar bone. Macrophages occurred consistently near blood vessels both in areas of tension and in areas of resorption. These are multipotent cells that obviously influence the remodeling process.

Alveolar Process↗
PubMed1982

Orthopedic expansion and protraction of the maxilla in cleft palate patients--a new treatment rationale.

This preliminary report presents a treatment rationale for cleft lip and palate patients who display underdevelopment of the midfacial complex in the deciduous dentition. In order to create more favorable conditions for midfacial growth, transverse expansion followed by anterior orthopedic traction of the maxillary complex is performed in the deciduous dentition, applying principles introduced by Delaire. A clinical procedure, based on fixed appliances and compatible with edgewise technique has been developed. A treated patient with indicator implants is presented.

Age Factors↗
PubMed1982

Craniofacial morphology in six-year-old Norwegian boys with complete cleft of lip and palate.

Twenty-nine Norwegian boys, 9 with complete bilateral cleft lip and palate and 20 with complete unilateral cleft lip and palate, were studied at 6 years of age before any orthodontic treatment had been performed. After the introduction in 1970 of a new surgical procedure involving early periostoplasty and bone formation in the cleft area corresponding to the alveolar process, the craniofacial growth pattern of these cleft groups still deviate from that of a normal control material. The growth pattern of the Bergen-patients does not seem to differ from patients where early periostoplasty is not performed and where the hard palate is closed 4-5 years later.

Cephalometry↗
PubMed1977

Orthodontic root resorption studied by electron microscopy.

The present study supports previous findings that root resorption takes place simultaneously with and after the elimination of hyalinized tissue. The cementoid layer and the more mature periodontal collagen fibers adjacent to cementum are possible barriers preventing root resorption. The microenvironment around hyalinized tissue is favorable for the introduction of hard-tissue resorbing cells. The findings show that the elimination of hyalinized tissue leads to the removal of the cementoid and the mature collagen thus leaving a raw cemental surface without a barrier. It is therefore hypothesized that such an area is readily attacked by odontoclasts. Once resorption lacunae are established, the cementum is resorbed from the rear as an undermining process. By continued orthodontic force application the resorption process will proceed even after all hyalinized tissue is eliminated. If the orthodontic force is discontinued or falls under a certain level, the resorption lacunae are repaired.

Animals↗
PubMed1976

Ultrastructural changes in tension zones of rat molar periodontium incident to orthodontic tooth movement.

The purpose of this study was, by introducing transmission electron microscopy, to clarify fine details of tissue reactions in the periodontal ligament on the tension side. A preliminary investigation was undertaken on nine rats in which experimental tooth movement lasted 2 days, 14 days, and 28 days. It was hoped that these new observations might help in the planning and directing of further studies. A marked increase of interstitial spaces between the formed ligament structures of the periodontal ligament was characteristic of the initial phases of tension. The cells and the endoplasmic reticulum within the cells were spindle shaped and oriented in the direction of strain. Occasionally, collagen fibrils were observed within the cytoplasm of fibroblasts. During experimental tension a higher prevalence of elastic fibers was observed and new details of the reaction of collagen fibrils were obtained. The new cementum and bone deposited during the experiment were studied. The preliminary study indicated that electron microscopy may become a valuable tool for the study of the tension side.

Alveolar Process↗