Biomedical subjects

O Krogstad

Publications and source records attributed to O Krogstad.

At least 19 recordsLinked to original sources

PubMed2001

Obstructive sleep apnea: a canonical correlation of cephalometric and selected demographic variables in obese and nonobese patients.

One hundred male obstructive sleep apnea (OSA) patients were classified into 2 groups on the basis of body mass index (BMI): 43 nonobese (BMI < 30 kg/m2) and 57 obese (BMI > or = 30 kg/m2) patients. A comprehensive cephalometric analysis with a multivariate statistical method was performed in order to define the different principal components (PCs) of cervico-craniofacial skeletal and upper airway soft tissue morphology in each group and how they contributed to selected elements of the patient demographic data, ie, apnea-hypopnea index (AHI), nocturnal oxyhemoglobin saturation, and BMI. Thirty cephalometric variables of cervico-craniofacial skeletal morphology were reduced to 8 PCs describing 84.4% and 85.4% of the total variance in obese and nonobese OSA patients, respectively. Sixteen cephalometric variables of hyoid bone position and head posture were reduced to 4 PCs describing 84.4% and 85.9% of the total variance in obese and nonobese OSA patients, respectively. Twenty cephalometric variables of upper airway soft tissue morphology were reduced to 7 PCs describing 89.5% and 84.6% of the total variance in obese and nonobese OSA patients, respectively. For further analysis of PCs, a stepwise multiple regression analysis was chosen. Two dependent variables of interest are the minimal distance of the posterior pharyngeal airway space (PASmin) and AHI. PASmin accounted for 95.3% (obese OSA group) and 74.3% (nonobese OSA group) with 7 PCs and AHI for 46% with 3 PCs in both groups. Three canonical variables and their correspondents with different loadings were established differently for both OSA groups. A canonical correlation successfully clarified the complexity of simultaneous relationship of the relevant variables. These analyses are proved useful to demonstrate the relationship of cervico-craniofacial skeletal and upper airway soft tissue morphology and selected demographic data. This lays down a basis for understanding the complicated pathogenic components of obese and nonobese OSA patients.

Adult↗

PubMed2001

Factors influencing the predictability of soft tissue profile changes following mandibular setback surgery.

The objective of this cephalometric study was to assess long-term changes in the soft tissue profile following mandibular setback surgery and investigate the presence of factors that may influence the soft tissue response to skeletal repositioning. The subjects enrolled were 80 consecutive mandibular prognathism patients operated with bilateral sagittal split osteotomy and rigid fixation. Lateral cephalograms were taken at 6 occasions: immediate presurgical, immediate postsurgical, 2 and 6 months postsurgical, and 1 and 3 years postsurgical. The subjects were grouped according to gender and magnitude of setback. Ratios of soft tissue to hard tissue movements were calculated for the subgroups. Females generally demonstrated greater ratios than males with a statistically significant difference for the upper lip and chin (P < .05). Postsurgical alterations in the profiles were more predictable in patients with larger setbacks compared to patients with smaller ones. Skeletal relapse had a profound influence on long-term profile changes. Based on these findings, it is proposed that the database used in prediction software be adjusted to account for such factors in an attempt to improve the accuracy of computerized treatment simulations.

Adult↗

PubMed2001

Plate fixation of extra-oral subcondylar ramus osteotomy for correction of mandibular prognathism: clinical aspects and short term stability.

AIM: The present study describes an extra-oral approach for subcondylar oblique ramus osteotomy using stable fixation for setback of the mandible. The aim was to investigate the incidence of neurosensory disturbances of the mandibular nerve, evaluate facial scar appearance, and assess skeletal stability following the procedure. METHODS: Forty-two consecutive patients with mandibular prognathism were operated upon using the subcondylar oblique ramus osteotomy and plate fixation. The patients were followed up for 6 months following surgery. Intra-operative and postoperative complications, neurosensory function, and facial scar characteristics were recorded. Lateral cephalograms were available immediately before operation, and immediately after operation and 6 months postoperatively. Skeletal stability was based on cephalometric assessment. RESULTS: Among the 19 patients operated earliest, neurosensory disturbances were recorded in five individuals at the 6 month follow-up. In the subsequent group of 23 patients, no disturbances were reported. All but two patients were not concerned about the facial scar 6 months postoperatively. Mean anterior relapse at the 6 month follow-up was 0.5 mm, representing 9% of the surgical setback. CONCLUSION: Extra-oral subcondylar oblique ramus osteotomy with plate fixation is a stable procedure with a low incidence of neurosensory disturbances if the osteotomy is placed well behind the mandibular foramen. Facial scar appearance was rarely a matter of concern to the patients.

Adult↗

PubMed2001

Mandibular advancement surgery in high-angle and low-angle class II patients: different long-term skeletal responses.

The objective of this cephalometric study was to compare skeletal stability and the time course of postoperative changes in high-angle and low-angle Class II patients after mandibular advancement surgery. The subjects were 61 consecutive mandibular retrognathism patients whose treatment included bilateral sagittal split osteotomy and rigid fixation. The patients were divided according to the preoperative mandibular plane angle; the 20 patients with the lowest mandibular plane angle (20.8 degrees +/- 4.9 degrees ) constituted the low-angle group, while the 20 cases with the highest mandibular plane angle (43.0 degrees +/- 4.0 degrees ) represented the high-angle group. Lateral cephalograms were taken on 6 occasions: immediately before surgery, immediately after surgery, 2 and 6 months after surgery, and 1 and 3 years after surgery. Results demonstrated that the high-angle and low-angle groups had different patterns of surgical and postoperative changes. High-angle patients were associated with both a higher frequency and a greater magnitude of horizontal relapse. While 95% of the total relapse took place during the first 2 months after surgery in the low-angle group, high-angle patients demonstrated a more continuous relapse pattern, with a significant proportion (38%) occurring late in the follow-up period. Possible reasons for the different postsurgical response are discussed.

Adolescent↗

PubMed2001

Soft tissue profile changes following mandibular advancement surgery: predictability and long-term outcome.

The objectives of this cephalometric study were to assess long-term changes in the soft tissue profile following mandibular advancement surgery and to investigate the relationship between soft tissue and hard tissue movements. The sample consisted of 61 patients treated consecutively for mandibular retrognathism with orthodontic therapy combined with bilateral sagittal split osteotomy and rigid fixation. Lateral cephalograms were taken on 6 occasions: immediately before surgery, immediately after surgery, 2 and 6 months after surgery, and 1 and 3 years after surgery. Postsurgical changes in the upper and the lower lips and the mentolabial fold were more pronounced among low-angle cases compared with high-angle cases. In accordance with other studies, the soft tissue chin and the mentolabial fold were generally found to follow their underlying skeletal structures in a 1:1 ratio. Because of the strong influence skeletal relapse has on soft tissue profile changes, alternative ratios of soft tissue-to-hard tissue movement that accounted for mean relapse were also generated. It is suggested that if a more realistic long-term prediction of the postsurgical soft tissue profile is desirable, then ratios incorporating mean relapse should be used rather than estimates based on a 1:1 relationship.

Adolescent↗

PubMed2000

Obstructive sleep apnoea: multiple comparisons of cephalometric variables of obese and non-obese patients.

BACKGROUND: Pathogenesis of obstructive sleep apnoea (OSA) is complex and not yet fully understood. Several factors contribute to OSA severity. Obesity is believed to play an important role. Nevertheless, not all OSA patients are obese. Therefore, the different features that cause nocturnal upper airway obstruction in obese and non-obese OSA patients could be expected. PURPOSE: To investigate the different components of cervico-craniofacial skeletal and upper airway soft tissue morphology among obese OSA, non-obese OSA patients and the controls. PATIENTS: One hundred male OSA patients were classified into two groups on the basis of body mass index (BMI) as obese (BMI > or = 30 kg/m2) and non-obese (BMI < 30 kg/m2). Consequently, 57 obese and 43 non-obese OSA patients were examined and compared with a control group of 36 healthy males. STUDY DESIGN: A comprehensive cephalometric analysis of cervico-craniofacial skeletal and upper airway soft tissue morphology was performed. Sixty-eight cephalometric variables were compared among the three groups by one way analysis of variance with Bonferroni's test. RESULTS: Both OSA groups had aberrations of cervico-craniofacial skeletal as well as upper airway soft tissue morphology when compared with the controls. These anatomic deviations were confined to cervico-craniofacial skeletal structures in the non-obese OSA patients, whereas the obese OSA patients had more abnormalities in the upper airway soft tissue morphology, head posture and position of the hyoid bone. CONCLUSION: The findings imply that there should be different treatment regimens for the two subgroups of OSA patients. Cephalometric analysis together with various considerations of BMI is highly recommended as one of the most important tools in diagnosis and treatment planning for OSA patients.

Adult↗

PubMed2000

Surgical mandibular advancement and changes in uvuloglossopharyngeal morphology and head posture: a short- and long-term cephalometric study in males.

The aim of the present study was to investigate, by means of an extensive cephalometric examination, the alterations which took place in hyoid bone position, head posture, position and morphology of the soft palate, and tongue and sagittal dimensions of the pharyngeal airway after mandibular advancement osteotomy for the correction of mandibular retrognathism. The sample consisted only of adult males who underwent mandibular advancement by bilateral sagittal ramus split osteotomy (BSRO) with rigid fixation. Profile cephalograms were obtained 1-3 days before surgery (20 subjects), and 6 months (20 subjects) and 3 years (19 subjects) after the surgery. Statistical evaluation was performed by paired Student's t-test and Pearson product moment correlation analysis. At the short-term follow-up, hyoid bone and vallecula assumed a more superior (AH perpendicular FH, AH perpendicular ML, AH perpendicular S, V perpendicular FH) and anterior position (AH-C3 Hor, V-C3), which was maintained at the long-term follow-up. The soft palate (NL/PM-U) became more upright at the short-term follow-up. The tongue demonstrated a transient increase in height (H perpendicular VT) and a less upright position (VT/FH) at the long-term observation. In addition, a more upright cervical spine (OPT/HOR, CVT/HOR) was recorded at the long-term follow-up. The pharyngeal airway space at the level of the oropharynx (U-MPW) and the retroglossal space at the base of the tongue (PASmin) showed an increase in the sagittal dimension at the short-term follow-up. Significant widening at the PASmin level was sustained at the long-term follow-up, indicating that mandibular advancement osteotomy could increase airway patency and be a treatment approach for sleep apnoea in selected patients.

Adult↗

PubMed2000

Surgical mandibular setback and changes in uvuloglossopharyngeal morphology and head posture: a short- and long-term cephalometric study in males.

A detailed cephalometric analysis was conducted on a sample of 31 adult males who underwent correction of mandibular prognathism by mandibular setback osteotomy (BSRO) with rigid fixation to evaluate the changes in uvuloglossopharyngeal morphology, hyoid bone position and head posture. Lateral cephalograms were obtained 1-3 days prior to the operation and at standardized 6 months and 3 years post-operative follow-up. Statistical evaluation was performed by paired Student's t-test and Pearson product moment correlation analysis. Inferior position of the hyoid bone (AH perpendicular FH, AH perpendicular ML, AH perpendicular S) and valeculla (V perpendicular FH) was recorded at the 6-month follow-up, a transient finding as at 3 years almost complete recovery to their pre-surgical position was noted. No posterior displacement of the above structures (AH-C3 Hor, V-C3) was recorded. Soft palate length (pm-U) was increased and maintained at the long-term follow-up while its posture (NL/pm-U) became less upright. The tongue showed increased length (V-T) and sagittal area (TA) and a more upright posture (VT/FH) at the late follow-up. Increased contact length between tongue and the soft palate (CL) and less residual oropharyngeal area [area not occupied by soft tissues, (TA + SPA)/OPA] was found at the long-term follow-up. Craniocervical agulation (NSL/OPT, NSL/CVT) was increased indicating cervical hyperflexion at the 3-year follow-up. Reduction of the sagittal dimension of the oropharyngeal airway space (U-MPW) appeared at the first follow-up and was sustained at the longest follow-up which, in conjunction with the decrease in residual oropharyngeal area, could raise questions regarding airway patency after mandibular setback osteotomy.

Adult↗

PubMed2000

Obstructive sleep apnea (OSA): a cephalometric analysis of severe and non-severe OSA patients. Part II: A predictive discriminant function analysis.

One hundred male obstructive sleep apnea (OSA) patients were classified into 2 groups on the basis of apnea-hypopnea index (AHI) as severe (AHI > or = 50) and non-severe (AHI < 50). A comprehensive cephalometric analysis of cervicocraniofacial skeletal and upper airway soft tissue morphology was performed in 51 non-severe and 49 severe OSA patients. In addition, a multivariate statistical method (principal component, analysis and predictive discriminant analysis) was performed to identify the components that could correctly differentiate the severe from the non-severe OSA patients. Eight principal components (PCs) of cervicocraniofacial skeletal morphology, 4 PCs of hyoid bone position and head posture, and 7 PCs of upper airway soft tissue morphology, together with the selected demographic variables, were deduced to formulate a linear canonical discriminant function. The equation of a 9-variable model was generated as follows: PDF score = 4.127 - 0.144 (Body Mass Index) - 0.376 (PC1.1) + 0.311 (PC1.4) + 0.214 (PC1.5) + 0.075 (PC 2.1) - 1.309 (PC2.3) + 0.708 (PC3.2) - 0.059 (PC3.3) + 0.609 (PC3.6). The cutoff score was -0.03899. The overall rate of correct classification was 83%. The results showed that Body Mass Index and 8 other PCs contributed significantly to the OSA severity. These analyses are proven to be a useful adjunctive diagnostic tool to select optimal treatment regimens for OSA patients with varying degrees of severity.

Aged↗

PubMed2000

Obstructive sleep apnea (OSA): a cephalometric analysis of severe and non-severe OSA patients. Part I: Multiple comparison of cephalometric variables.

One hundred male obstructive sleep apnea (OSA) patients were classified into 2 groups, on the basis of Apnea-Hypopnea Index (AHI), as severe (AHI > or = 50) and non-severe (AHI < 50). A comprehensive cephalometric analysis of cervicocraniofacial skeletal morphology and upper airway soft tissue morphology was performed in 51 non-severe OSA patients, 49 severe OSA patients, and 36 controls with the purpose of examining the different features among these 3 groups. Sixty-eight cephalometric variables were compared among these 3 groups by 1-way analysis of variance with post hoc Bonferroni test. The results showed that both OSA groups had aberrations of cervicocraniofacial skeletal morphology and upper airway soft tissue morphology versus the controls. Severe OSA patients demonstrated increased maxillo-mandibular retrognathism, with a high mandibular plane angle resulting from increased anterior lower facial height and decreased posterior lower facial height, versus the non-severe OSA group. The craniocervical extension, forward head posture, inferiorly positioned hyoid bone, and the enlarged and elongated soft palate and upright tongue posture were more exaggerated as well. These findings imply that there should be different treatment regimens for the 2 subgroups of OSA patients to achieve treatment success. Cephalometric analysis is therefore highly recommended to verify the aberrant cervicocraniofacial morphology in severe and non-severe OSA patients.

Adult↗

PubMed2000

Long-term stability of mandibular setback surgery: a follow-up of 80 bilateral sagittal split osteotomy patients.

The objective of this cephalometric study was to evaluate skeletal stability and time course of postoperative changes in 80 consecutive mandibular prognathism patients operated with bilateral sagittal split osteotomy (BSSO) and rigid fixation. Lateral cephalograms were taken on 6 occasions: immediately preoperative, immediately postoperative, 2 and 6 months postoperative, and 1 and 3 years postoperative. The results indicate that BSSO with rigid fixation for mandibular setback is a fairly stable clinical procedure. Three years after surgery, mean relapse at pogonion represented 26% of the surgical setback (19% at point B). Most of the relapse (72%) took place during the first 6 months after surgery. Clockwise rotation of the ascending ramus at surgery with lengthening of the elevator muscles, though evident in this study and apparently responsible for the early horizontal postoperative changes, does not seem to be associated with marked relapse. Changes occurring in some of the younger patients between 1 and 3 years postoperatively are likely to be manifestations of late mandibular growth.

Adolescent↗

PubMed2000

Stability of extraoral vertical ramus osteotomy: plate fixation versus maxillomandibular/skeletal suspension wire fixation.

The objective of this cephalometric study was to evaluate skeletal stability and time course of postoperative changes in 2 groups of mandibular prognathism patients following extraoral oblique vertical ramus osteotomy (VRO). One group (n = 22) received maxillomandibular fixation and skeletal suspension wires (MMF group) for a period of 8 weeks. In the other group (n = 22), the segments were rigidly fixed with plates and the patients were allowed to function immediately after surgery. Lateral cephalograms were taken on 5 occasions: immediately presurgical, immediately postsurgical, 8 weeks postsurgical, 6 months postsurgical, and 1 year postsurgical. During the first 8 weeks after surgery, the MMF group demonstrated posterior movement of the mandible, with an increase in mandibular plane angle, shortening of the rami, and dental compensations. Upon release of MMF and skeletal suspension wiring, a small anterior relapse tendency was observed, but the net setback 1 year after surgery was still greater than the actual surgical setback. In the plate fixation group, postoperative changes were mainly in the form of a small anterior relapse tendency in the range of 10% of the surgical setback. The results indicate that the use of plate fixation with VRO, while eliminating the inconvenience for the patient of several weeks of MMF and preventing the early side effects observed in the MMF group, also resulted in a more predictable surgical procedure, with excellent stability 1 year after surgery.

Adult↗

PubMed1999

Morphology and growth in convex profile facial patterns: a longitudinal study.

Two groups of females, one with normal anteroposterior jaw-base relationships and the other with distal jaw-base relationships, were selected at age 6 and compared longitudinally up to age 18. The purposes of this study were, first, to reveal morphological factors that caused or contributed to a distal jaw-base relationship, and second, to compare growth in the two groups. A distal jaw-base relationship is not a morphological entity caused by some specific aberration in the cranial base or jaws. Rather, it is the result of a combination of predisposing deviations with varying degrees of gravity. A short mandibular corpus and a large MP-SN angle were the only deviations with significant group differences. Distal jaw-base relationships generally worsened with age as compared with normal anteroposterior jaw-base relationships. Inadequate increase in mandibular corpus length in the 6- to 12-year period contributed to the worsening, as did the mandible growing more vertically than normal after age 12.

Adolescent↗

PubMed1999

Adult craniocervical and pharyngeal changes--a longitudinal cephalometric study between 22 and 42 years of age. Part I: Morphological craniocervical and hyoid bone changes.

The purpose of this study was to investigate longitudinally, by cephalometric means, alterations in craniocervical morphology and hyoid bone position in adult males and females, in three different age groups at 10-year intervals, and to compare the changes between the two genders. The material consisted of three series of cephalograms of 26 males and 24 females with approximately a 10-year interval between each series. Alterations with increasing age in males and females included: 1 An increase in anterior and posterior facial height in both genders, a reduction in mandibular prognathism, and an increase in the mandibular plane angle in females only. 2 The hyoid bone assumed a more inferior position in relation to different skeletal structures for both sexes. 3 Head posture alterations were similar for the male and female group over time. The overall significant inter-sex changes over a 20-year period were a reduction in mandibular prognathism, an increase in the mandibular plane angle in females, and a more inferior position of the hyoid bone in males.

Adult↗

PubMed1999

Adult craniocervical and pharyngeal changes--a longitudinal cephalometric study between 22 and 42 years of age. Part II: Morphological uvulo-glossopharyngeal changes.

The purpose of this study was to investigate, by cephalometric means, longitudinal alterations in uvulo-glossopharyngeal morphology in adult males and females, at three different ages with 10-year intervals, and to compare the changes between the two genders. The material consisted of three series of cephalograms of 26 males and 24 females, with approximately a 10-year interval between each series. Alterations with age in males and females included: 1 An increase in the length, thickness, and sagittal area of the soft palate, with a more upright position for both genders. 2 A more upright tongue position and caudally-extended tongue mass for both sexes was found, and the sagittal area of the tongue was significantly increased only in males. 3 There was a decrease in the sagittal dimension of the oropharynx, and at the minimal distance between the base of the tongue and the posterior pharyngeal wall in both males and females. The overall significant inter-sex differences, over a 20-year period, were that males showed a more upright tongue position and more caudally-extended tongue mass, a greater reduction in sagittal dimension of the minimal pharyngeal airway space, a greater increase in the sagittal area of the soft palate, and an increase in the tongue area.

Adult↗

PubMed1999

Duration of orthodontic treatment involving orthognathic surgery.

The purpose of this study was to analyze factors influencing the duration of treatment in a sample of patients treated by a combined orthodontic/orthognathic surgery approach. Presurgical and postsurgical treatment times were assessed for 315 patients processed through an orthognathic team over a 7-year period. The median total treatment duration for all patients was 21.9 months, the median presurgical duration was 15.4 months, and the median postsurgical duration was 5.9 months. Treatment involving extractions resulted in significantly increased presurgical and total treatment times. Treatments performed in the university clinic showed reduced presurgical duration and increased postsurgical duration compared to treatments carried out by specialists outside the university. Presurgical, postsurgical, and total treatment times were significantly reduced when the orthodontist had treated 10 or more patients during the period. An earlier regimen of orthodontic treatment did not appear to have a significant effect on treatment duration.

Adolescent↗

PubMed1999

Obstructive sleep apnea: a principal component analysis.

A principal component analysis was performed on the cephalometric variables of 100 male obstructive sleep apnea (OSA) patients. Thirty cephalometric variables of cervicocraniofacial skeletal morphology were reduced to 8 principal components (PCs), which described 83.2% of the total variance. Sixteen cephalometric variables of hyoid bone position and head posture were reduced to 4 PCs, which described 85.5% of the total variance. Twenty cephalometric variables of upper airway soft tissue were reduced to 7 PCs, which described 83.7% of the total variance. These PCs described the actual characteristics of the OSA patients examined. For further analysis of PCs, stepwise multiple regression analysis was chosen. Two dependent variables of interest are the minimal distance of posterior pharyngeal airway space (PASmin) and the Apnea-Hypopnea Index (AHI). Seven PCs accounted for 79.4% of the variance of PASmin and 3 PCs accounted for 37.6% of the variance of AHI. Both principal component analysis and multiple regression analysis provide multivariate data analysis that is very useful in sorting out and clarifying the complexity of the interrelated cervicocraniofacial skeletal morphology and upper airway soft tissue in OSA patients.

Adult↗

PubMed1998

Validity of the Demirjian method for dental age estimation when applied to Norwegian children.

Dental age was studied in a sample of 261 Norwegian children by using the maturity standards of Demirjian & Goldstein (1976) to examine the applicability of these standards as a reference for overall dental maturity in a Norwegian population. The sample comprised 128 boys and 133 girls included in 'the Oslo Growth Material', from whom orthopantomograms (total, 783) had been longitudinally obtained, with intervals of about 3 years and covering 3 age spans (5.5-6.5 years, 8.5-9.5 years, and 11.5-12.5 years), each divided into 3 half-year age groups. Reliability was analyzed by repeated assessments of 134 of the radiographs, and the overall mean difference between duplicate dental age determinations was 0.5 months for intra- and 1.8 months for inter-examiner comparisons. The Norwegian children were generally somewhat advanced in dental maturity compared with the French-Canadian reference sample. Among the boys the mean difference between dental age and chronologic age varied in the different age groups from 1.5 to 4.0 months. Among the girls the difference increased with age, varying from 0 to 3.5 months in the younger age groups (5.5 to 9.0 years) and from 4.5 to 7.5 months in the age groups 9.5 years and above. The variability in individual dental age was marked and increased with age. For the older age groups 95% of the individual age estimates were within +/-2 years of the real age. The applied standards appear to be adequate for studying dental age in groups of children from a Norwegian population. Given the considerable individual variation in dental maturity, estimation of chronologic age in individual children should be supplemented by other indicators of biologic maturity.

Age Determination by Teeth↗