Biomedical subjects
Publications and source records attributed to O Krogstad.
Aplasia of the mandibular condyle is extremely rare when not seen as a part of a syndrome. A case, apparently with no soft tissue aberrations, is described and a possible connection with the hemifacial microsomia syndrome is discussed.
Temporary mental paresthesia of the lower lip as a result of orthodontic treatment is extremely rare. Only two cases seem to have been reported earlier, a further case is described and discussed. The cause of this uncommon complication in the present case is obviously the close relationship between the distal root of the lower left second permanent molar and the mandibular canal.
This study compares craniofacial structure and soft tissue profile in persons with mild hypodontia (group I: 2 to 5 congenitally missing teeth, n = 43), moderate hypodontia (group II: 6 to 9 congenitally missing teeth, n = 15) and severe hypodontia (group III: 10 or more congenitally missing teeth, n = 29) with the structure of persons without hypodontia and with normal occlusion (n = 50). The mean age was about 12 years. In group I, the lower second premolars were the most frequently missing teeth, followed by the upper second premolars and the upper lateral incisors. The relative prevalence of missing second premolars decreased with increasing severity of hypodontia. No consistent pattern could be observed when more than five teeth were missing, indicating a different genetic mechanism than for mild hypodontia. A significant retroclination of the incisors and an increased interincisal angle were observed with increasing severity of hypodontia. This was accompanied by a reduction of lip protrusion, being most evident for the upper lip. Increasing numbers of missing teeth resulted also in a decrease in the mandibular plane angle and a reduction in the anterior lower facial height. Few differences in the skeletal parameters were observed. It was concluded that the typical dentofacial structure in persons with advanced hypodontia may be due to dental and functional compensation rather than to a different growth pattern.
A comprehensive cephalometric analysis of cervico-craniofacial skeletal morphology in 100 male patients with obstructive sleep apnoea (OSA) and 36 male controls was performed. The significant aberrations in the OSA group feature: (1) shorter dimension of cranial base with slight counter-clockwise rotation and depression of clivus; (2) shorter maxillary length with normal height; (3) maxillo-mandibular retrognathia related to nasion perpendicular plane (N perpendicular FH) despite normal angles of prognathism; (4) 47 per cent of the OSA group had mandibular retrognathia; (5) increased anterior lower facial height and mandibular plane angle; (6) reduced size of bony pharynx; (7) inferiorly positioned hyoid bone at C4-C6 level; (8) deviated head posture with larger cranio-cervical angle. Cephalometric analysis is highly recommended in OSA patients as one of the most important tools in diagnosis and treatment planning.
A comprehensive cephalometric analysis of uvulo-glossopharyngeal morphology in 100 patients with obstructive sleep apnoea (OSA) and 36 controls was performed. The aberrations in OSA patients included: 1. Increased length, thickness, and sagittal area of soft palate (PM-U; SPT; SPA: P < 0.001) with a more upright position (NL/PM-U: P < 0.05) and 15 per cent more pharyngeal area occupation [SPA/(OPA-OA): P < 0.001]. 2. The contact length between the soft palate and the tongue was increased approximately two-fold (CL: P < 0.001). 3. The sagittal area of the tongue was 10 per cent larger (TA: P < 0.001) despite similar length and height and 3 per cent more oral area occupation (TA/OA: P < 0.05). 4. More upright tongue position (VT/FH: P < 0.05) and caudally extended tongue mass (V perpendicular FH: P < 0.05). 5. Decreased sagittal dimensions of nasopharynx (pm-UPW: P < 0.001), velopharynx (U-MPW: P < 0.001) and minimum distance between the base of the tongue and the posterior pharyngeal wall (PASmin: P < 0.001). 6. The residual oropharyngeal area (area not occupied by soft tissues) was 9 per cent less due to larger tongue and soft palate [(TA+SPA)/OPA: P < 0.001]. Cephalometric analysis is highly recommended in OSA patients as one of the most important tools in diagnosis and treatment planning.
The purpose of this study was to determine if mandibular incisors could be proclined markedly without increasing the potential for relapse of crowding. Patients with surgically treated mandibular prognathism were selected. In 29 patients the mandibular incisors were proclined more than 10 degrees during the presurgical orthodontic phase. The remaining 33 patients had only minimal change in incisor inclination. A long-term follow-up examination was performed 10.0 (SD 2.3) and 11.1 (SD 3.1) years postoperatively in 26 and 24 patients, respectively. Study casts were measured before and after treatment, three years after surgery, and long-term. Cephalograms were evaluated before and after treatment, immediately before and after surgery, and three years after surgery. Prior to therapy the patients treated with presurgical proclination had less dental arch length and more retroclined and crowded mandibular incisors than the patients in the other group. No differences in parameters were observed at later intervals. Dental arch length and intercanine width decreased and incisor irregularity increased in both groups during the follow-up periods. No intergroup differences in changes were observed. Indications for proclination of mandibular incisors are discussed.
This article deals with orthodontics and maxillofacial surgery as an integrated treatment. During the last fifteen years orthognathic surgery has made extensive progress, and almost all great malocclusions combined with facial anomalies can be treated with good and stable results. Because the surgical methods are more refined and sophisticated, greater demands have been put on the planning of the treatment making this a team effort between the orthodontist and the surgeon. Treatment of anterior crossbite, extreme overjet and open bite are shown as examples of what can be achieved by this team approach. The outlines of the treatment are given and it is stressed that the orthodontic treatment must be done with fixed appliances. The complications are few, and the results are usually stable. This integrated treatment can therefore be recommended to those patients who are motivated for it and really need it.
Facial skeletal morphology was studied by cephalometric analysis in 25 patients with obstructive sleep apnoea syndrome (OSAS) and ten controls. The hyoid bone was more inferiorly positioned in patients (at the level of cervical vertebrae C4-C6) than in controls (C3-C4 level). The height and length of the nasal cavity was normal, while the length of the bony nasopharynx was moderately reduced. The mandibular plane inclination was slightly larger in patients as was the anterior face height. Mandibular retrognathia was demonstrated in six patients (24 per cent), but the angles of maxillary and mandibular prognathism was within normal limits when the group was considered as a unity. Cephalometric analysis is highly recommended as a diagnostic aid in OSAS patients, especially when surgical intervention is considered.
Oropharyngeal soft tissue profiles were studied by cephalometric analysis in 25 patients with obstructive sleep apnoea syndrome (OSAS) and 10 controls. The length of the soft palate was significantly higher in patients (48.0 +/- 4.3 mm. (mean +/- SD) than in controls (35.3 +/- 4.6 mm.) (p less than 0.001), as was the distance of close contact between the tongue and the soft palate (23 +/- 12 mm. and 10 +/- 8 mm., respectively) (p less than 0.01). The area of the soft palate, measured in the sagittal plane, was 4.85 +/- 0.80 cm.2 and 2.88 +/- 0.62 in the patient and the control group, occupying 39 +/- 8 per cent and 21 +/- 5 per cent of the pharyngeal area (p less than 0.001). The lower outline of the tongue, represented by the line between vallecula (V) and the hyoid bone (AH) was more inferiorly positioned in patients, apparently giving the tongue a more upright position with more of the tongue tissue at the hypopharyngeal level than found in normals. The pharyngeal airway space had significantly reduced anteroposterior dimensions both at the nasopharyngeal and velopharyngeal level (P less than 0.001) as well as the hypopharyngeal level (p less than 0.05). Cephalometric analysis is highly recommended as a valuable tool in the presurgical evaluation of OSAS patients.
The present study was undertaken to examine whether excessive proclination of mandibular incisors results in gingival retraction. In patients with surgically treated mandibular prognathism, 29 with more than 10 degrees proclination of mandibular incisors and 33 with minimal change in incisor inclination during presurgical orthodontic phase were selected. A total of 21 and 19 patients, respectively, could meet for a clinical follow-up examination including Visible Plaque Index, Gingival Bleeding Index, probing pocket depth, and length of supracrestal connective tissue attachment. Study models and intraoral color slides were also made. The mean postoperative times at this examination were 7.8 (SD 2.5) and 8.1 (SD 2.8) years, respectively. Clinical crown height was measured on the study models taken before and after appliance therapy, at the 3-year postoperative control (check) and at the follow-up examination. The number of teeth with recession was determined from the color slides taken at the same intervals; the thickness of the symphysis was measured on the cephalograms taken before treatment. The results demonstrated significantly more increase in clinical crown height and significantly more teeth developing recession both during appliance therapy and during the period from removal of appliance to the 3-year postoperative control in the patients with excessive proclination than in the patients with minimal change in incisor inclination. The correlation coefficient between width of symphysis and increase in clinical crown height in patients with excessive proclination was statistically significant. Only minimal changes were observed from 3 years postoperatively to the follow-up examination. No differences in clinical measurements were observed between the groups and bone dehiscences were not found.
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Twenty individuals received an increased occlusal face height by orthodontic means (a partial bite-raising splint). After splint treatment some of the anterior teeth were capped at the new occlusal face height. The average increase from start of splint treatment till after crown cementation was 1.9 mm. The stability of the vertical relations of the face after this treatment was studied. The average observation time was 67 months, i.e. 5.5 years. The modes of reaction were highly individual. A certain average relapse of the occlusal face height did occur, mostly in the course of the first 6 months after crown cementation. However, in no case did the increased face height revert to basis. In the period from 6 to 67 months after crown cementation twelve out of nineteen patients showed practically completely stable vertical relations.
The effect of orthodontic treatment on the prevalence of Streptococcus mutans was investigated in 14 subjects. Insertion of appliances tended to give a transient decrease in S.mutans levels, in both plaque and saliva, possibly due to elimination of S.mutans reservoirs by the banding procedure. After 3 months of extensive banding, the S.mutans proportions surpassed pretreatment levels in saliva and on banded teeth, whereas unbanded surfaces only showed a slight increase. It was thus concluded that creation of new retentive areas favors the local growth of S.mutans, which in turn increases the general infection level of this organism. Time was, however, needed before elevated levels were reached. Insertion of appliances tended to eliminate the characteristic gradient of S.mutans levels within the dental arches.
In a previous paper it was maintained that the effect of the permanent use of an anterior partial bite-raising splint was an intrusion of the front teeth and an eruption of the others. However, the effect might have been merely a change in the inclination of the front teeth. The present study comprised the same material as earlier. Linear and angular changes in the position of upper and lower incisors were measured on cephalometric radiographs. In the upper jaw a possible average proclination occurred, whereas in the lower jaw no or only a very small retroclination took place. The values were well within the method error, and it was concluded that the effect of the splint had been one of intrusion of the upper and lower front teeth and not merely a change in their inclination.
20 patients (18 - 50 years) with pathological attrition of upper and/or lower anterior teeth were treated, as a temporary measure, by means of a partial chrome-cobalt splint covering the palatal surfaces of the six upper front teeth. Tantalum implants to provide reference points were placed in the basal portion of upper and lower jaw bones. Lateral cephalometric radiographs were taken with and without the splint at the beginning of treatment and thereafter every two months till the difference between measurements was as small as possible. Changes in the occlusal face height were evaluated. Measurement reliability proved to be very high. Continuous use of the splint caused intrusion of the front teeth and eruption of the others in all patients. The intrusion was on an average 1.05 mm and the eruption 1.47 mm after 6 - 14 months, indicating a possible potential for tooth eruption in human adults. More eruption than intrusion appeared to take place in the youngest age groups. Sexual differences could not be established. Use of the splint did not cause the common symptoms of mandibular dysfunction. Lisping was the most serious complaint.