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Biomedical subjects

K Vargervik

Publications and source records attributed to K Vargervik.

At least 19 recordsLinked to original sources
PubMed1999

Auditory and facial nerve dysfunction in patients with hemifacial microsomia.

BACKGROUND: Hemifacial microsomia (HFM) is a common craniofacial disorder characterized by a wide spectrum of anomalies, including conductive hearing loss due to external and middle ear deformities. However, the prevalence of sensorineural hearing loss (SNHL) as well as facial nerve dysfunction is underappreciated. OBJECTIVE: To determine the frequency of auditory and facial nerve dysfunction and its relationship to more severe forms of bilateral HFM. DESIGN: Retrospective medical record review to characterize the clinical severity of HFM and the prevalence and nature of the associated auditory and facial nerve dysfunction. SETTING: Center for Craniofacial Anomalies at the University of California, San Francisco, Medical Center. PATIENTS: Ninety-nine pediatric patients with HFM evaluated at the University of California, San Francisco, Medical Center. MAIN OUTCOME MEASURES: The prevalence of SNHL and facial nerve dysfunction in this patient population and any associations between these 2 characteristics. RESULTS: Hearing loss was present in 74 (75%) of 99 patients, with a conductive component in 73 patients. Sensorineural hearing loss was present in 11 patients ( 11%), with mixed hearing loss in most patients. Fourteen patients required rehabilitation with auditory amplification. Nearly a quarter of the patients (22 [22%] of 99) had facial nerve dysfunction, but only 1 patient had facial palsy on the same side as the SNHL. There was a statistically significant association between having auricular abnormalities and conductive hearing loss or SNHL (P = .30 and .80, respectively). However, there was no statistically significant association between bilateral HFM and the occurrence of either SNHL or facial paralysis, nor was there an association between auditory and facial nerve dysfunction. CONCLUSIONS: Sensorineural hearing loss and facial nerve dysfunction are common in HFM. These findings have important implications in the treatment of patients with HFM.

Adolescent↗
PubMed1999

Placement of endosseous implants in children and adolescents with hereditary ectodermal dysplasia.

OBJECTIVE: The purposes of this investigation were to study the feasibility of placing endosseous implants in children and adolescents with ectodermal dysplasia and to assess the position and stability of such implants during growth. This article reports on 6 subjects with long-term follow-up. Study design. A prospective study was commenced in 1991. Patients with hereditary ectodermal dysplasia who were over the age of 5 years and who presented to the University of California San Francisco Ectodermal Dysplasia Clinic for dental treatment were included and maintained in the study. In each case, clinical and radiographic records were obtained before treatment, immediately after implant placement, at delivery of the prosthesis, and subsequently at yearly intervals. Six subjects are reported, 4 as members of the prospective study group and 2 who had been treated before the study began. RESULTS: A total of 41 implants (19 maxillary, 22 mandibular) were placed. The average follow-up after implant placement was 7.8 years (range, 6-11 years), and the average time since restoration was 6 years (range, 5-10 years). Forty implants successfully integrated and have been restored. There was no evidence that implant placement or prosthetic rehabilitation resulted in restriction of transverse or sagittal growth. One mandibular implant, placed in a partially dentate 5-year-old, became submerged because of adjacent alveolar development and required placement of a longer abutment. Four maxillary implants placed in a partially dentate 7-year-old also became submerged and required prosthetic revision and the placement of longer abutments. CONCLUSIONS: This preliminary report suggests that endosseous implants can be successfully placed and can provide support for prosthetic restoration in patients with hereditary ectodermal dysplasia. However, vertical dentoalveolar growth results in submergence of the implant relative to the adjacent natural dentition when implants are placed adjacent to erupting permanent teeth.

Adolescent↗
PubMed1998

Importance of the critical-size bone defect in testing bone-regenerating materials.

A substantial interest exists in developing substitute materials and human recombinant bone-inducing factors to enhance bone regeneration both in the craniofacial complex and in other parts of the skeleton. A persistent problem has been to find an animal model that allows for the comparison of different osteopromotive materials. The purpose of this investigation was 1) to determine whether a 5-mm calvarial defect in adult rats fulfilled the requirements of a critical-size bone defect and 2) to discuss the use of this animal model in assessing bone repair in the craniofacial region. Bilateral full-thickness calvarial defects were trephined in the calvarial bone of 56 5- to 6-month-old Wistar rats. Except for minor amounts of bone formation limited to the margins of the defect, none of the defects revealed any signs of spontaneous bone regeneration 6 and 12 months after surgery. The full-thickness 5-mm calvarial defects thus fulfill the criteria for a critical-size bone defect. This animal model allows for an experiment with a paired design, it avoids inclusion of the sagittal suture in the osseous defect, and it thereby minimizes morbidity by reducing the risk of damaging the midsagittal sinus. An adequate experimental model has been developed to evaluate the efficiency of osteopromotive materials in the healing of bone defects in the craniomaxillofacial region.

Animals↗
PubMed1998

Characteristics of jaw growth in cleidocranial dysplasia.

OBJECTIVE: The purpose of this pilot study was to assess craniofacial morphology in young and adult individuals with cleidocranial dysplasia (CCD). DESIGN: Craniofacial morphology in young individuals (primary dentition) and in young adults was compared with control data using ratios and angles obtained from lateral head films. SETTING: The CCD individuals were referred to the Center for Craniofacial Anomalies for diagnostic workup and treatment recommendations. SUBJECTS: The sample consisted of 14 Caucasians. The inclusion criterion for the young, prepubertal group (A) was complete primary dentition, and for the adult, postpubertal group (B), the eruption of all four first molars was required. INTERVENTIONS: No treatment other than extraction or surgical removal of selected primary or supernumerary teeth was performed. RESULTS: Both groups showed significantly smaller anterior upper face height compared with controls. Group B subjects demonstrated significantly smaller face height values than the controls in the A point-nasion-B point (ANB) angle, facial axis, mandibular plane angle, palatal plane/mandibular plane angle, and gonial angle. No significant differences were found between group A individuals and the controls for these measurements. The older group had shorter anterior lower face height compared with both anterior upper face height and posterior lower face height. CONCLUSIONS: Whereas young CCD subjects showed relatively normal jaw proportions and morphology of the mandible, older CCD individuals tended to have short lower face height, acute gonial angle, anterior inclination of the mandible, and mandibular prognathism. These differences can be attributed to pronounced horizontal mandibular growth resulting from lack of vertical maxillary growth and impaired eruption of permanent teeth.

Adolescent↗
PubMed1997

Birth prevalence, mutation rate, sex ratio, parents' age, and ethnicity in Apert syndrome.

Apert syndrome was studied to determine birth prevalence, mutation rate, sex ratio, parents' age, and ethnicity among 2,493,331 live births registered in the California Birth Defects Monitoring Program (CBDMP) from 1983 through 1993; 31 affected infants were identified. The sample was completed with an additional 22 cases from the Center for Craniofacial Anomalies (CCA), University of California, San Francisco, for a total of 53 affected children. Birth prevalence, calculated from the CBDMP subsample, was 12.4 cases per million live births (confidence interval [CI] 8.6,17.9). The calculated mutation rate was 6.2 x 10(-6) per gene per generation. Asians had the highest prevalence (22.3 per million live births; CI 7.1,61.3) and Hispanics the lowest (7.6 per million, CI 3.3-16.4). In the large population-based CBDMP subsample, there was an almost equal number of affected males and females, (sex ratio 0.94) but in the clinical CCA subsample, there were more affected females (sex ratio 0.79). For all cases, the mean age of mothers was 28.9+/-6.0 years, and of fathers was 34.1+/-6.2 years. Almost half of fathers were older than 35 years when the child was born; for more than 20% of cases, both parents were older than 35 years. These findings may support the view that point mutations appear to be more commonly associated with paternal than with maternal alleles. Representing the largest systematically ascertained population-based study of Apert syndrome to date, they provide a reliable basis for genetic counseling and decision-making, and for focused research to define the cause of this syndrome.

Acrocephalosyndactylia↗
PubMed1997

Dental development in Apert syndrome.

OBJECTIVE: Apert syndrome has been extensively studied and described. However, an area that has not been studied is the dental development of these individuals. The purpose of this study was to evaluate the development of the dentition and compare it with that of unaffected children. There appears to be clinical observations indicating delayed eruption of the permanent teeth in the Apert child. METHODS: This retrospective study examined all Apert syndrome patients from four craniofacial centers who had a panoramic radiograph taken before the age of 16 years. Thirty-six individuals, 19 boys and 17 girls ranging in age from 4.1 to 15.8 (mean = 9.3) years were examined. The seven left mandibular permanent teeth, second molar to central incisor, were rated on an eight-stage scale (A-H) using methods described by Demirjian and Goldstein (1976). The stage of each tooth was converted to the corresponding numeric value, and then all seven values were added to obtain a dental maturity score, which corresponded to a dental age, based on the sample of 4500+ normal children of the Demirjian et al. study. The dental age and chronologic age were length of delay was also determined. RESULTS: Thirty-one of 36 individuals had a dental age lower than their chronologic age. Compared to the normal sample, the mean developmental dental delay was 0.96 years (p < .001). The range in delay was 0.5 years advanced to 2.9 years delayed. There was a positive correlation to increased age with greater delay in dental development (p < .05). CONCLUSION: Our study confirmed our clinical impressions: The results showed a mean developmental delay of 0.96 years, with a trend of increasing delay with increased age. This positive correlation found between increased age and increased delay parallels the general growth of Apert children, with a greater degree of delay as the child grows older.

Acrocephalosyndactylia↗
PubMed1997

Placement of endosseous implants in grafted alveolar clefts.

OBJECTIVE: The purpose of this study was to determine the optimal timing for placement and to evaluate short- and long-term outcomes of endosseous implants in bone-grafted alveolar clefts. DESIGN: Fourteen patients who underwent alveolar cleft bone grafting (ACBG) and closure of an oronasal fistula followed by restoration of the missing lateral incisor tooth using endosseous implants (EI) were studied. The oronasal fistulae were closed using local flaps, and the alveolus was grafted with fresh autogenous iliac marrow. Endosseous implants were placed a minimum of 4 months following ACBG. The average age at ACBG was 20.35 years (range, 12-65 yr), and at implant placement 22.2 years (range, 15-66 yr). It was necessary to regraft the alveolar cleft region in six patients to provide adequate bone volume for implant placement. Those who required alveolar regrafting had an increased mean interval between the initial ACBG and planned implant placement compared to the patients with adequate bone available for implant placement 26.4 months (range, 4-46 mo) versus 15.75 months (range, 4-36 mo). RESULTS: Twenty-nine implants were placed in 14 patients, 9 outside of the cleft region and 20 in grafted alveolar clefts. Eighteen of 20 (90%) implants in the bone-grafted alveolar clefts have been successfully restored. The mean follow-up after implant placement was 39.1 months (range, 1-54 mo), and after restoration 28.5 months (range, 1-47 mo). CONCLUSIONS: Endosseous implants can be placed in bone-grafted alveolar clefts. Consideration should be given to the adequacy of graft volume and ridge morphology at the time of ACBG. The interval between ACBG and implant placement is important. The greater the interval beyond 4 months, the more likely there will be inadequate bone volume to accept an implant.

Adolescent↗
PubMed1996

Nasal growth in complete bilateral cleft lip and palate.

Forty-four lateral cephalograms from a sample of 15 white males with bilateral cleft lip and palate (BCLP) were evaluated to determine the growth pattern of the nose, identify timing of the nasal growth spurt, assess growth of the underlying bony elements relative to the nasal growth, and ascertain the relationship of the nose to the rest of the facial profile. The cephalograms (taken at ages 7.5 to 16.6 years) were divided into five groups according to age of subject. Fifteen variables related to soft tissue nose, nasal bone, maxilla, and facial convexity were assessed. Results of this investigation were as follows. First, the nose of subjects with BCLP grew more downward than forward. Second, the growth spurt occurred between the ages of 12 and 16 years. Third, forward growth of the nose was almost always found, whereas the maxilla becomes more retrusive. Fourth, the angle of soft tissue nasion (N')-pronasale (Prn)-soft tissue pogonion (Pog') had an average decrease of 3.56 degrees from age 8 to 16 years. Individual data showed that 12 of 15 patients had a decrease of this angle, whereas 3 had a small increase; 10 of 12 with a decrease demonstrated an increase of both sella-nasion (SN')-Prn and SN'-Pog'. The remaining 2 showed an increase of SN'-Prn and a decrease of SN'-Pog'. Thus, the profile of the nose (N'-Prn-Pog') became more convex over the observed period, which at least in part seemed to be due to the horizontal development of the nose itself.

Adolescent↗
PubMed1996

Human recombinant transforming growth factor-beta 1 in healing of calvarial bone defects.

Bone healing plays an important role in orthognathic and craniofacial surgery. Bone tissue repair and regeneration are regulated by an array of growth and morphogenetic factors. Osteogenesis proceeds through a cascade of molecular and cellular events sequentially coordinated by members of both the bone morphogenetic protein and transforming growth factor-beta (TGF-beta) families. The efficacy of a single application of 2, 5, or 10 micrograms of recombinant human (rh) TGF-beta 1 to promote bone regeneration in 5-mm experimental calvarial defects of adult male rats was assessed histologically and histomorphometrically. The histomorphometric results of the experimental site were compared with those of the contralateral control side. Dosegroup comparisons were also performed. None of the control and experimental bone defects demonstrated complete bone closure. Limited bone regeneration was found close to the margins of the defects. A statistically significant difference in volume fraction composition (bone, osteoid, and soft tissue) was found between the 5- and 10-microgram rhTGF-beta 1-implanted and control defects. No difference was found in the 2-microgram rhTGF-beta 1-implanted group. The percentage of bone closure was statistically significantly higher in the 5-microgram rhTGF-beta 1-implanted group than in the control group. The present findings indicate that a single application of different doses of rhTGF-beta 1 does not promote clinically relevant osteogenesis in membranous calvarial bone defects in adult rats.

Animals↗
PubMed1996

Airway changes after Le Fort III osteotomy in craniosynostosis syndromes.

The purpose of this study was to investigate changes in the nasopharyngeal airway and surrounding structures after Le Fort III advancement in Apert's and Crouzon's syndromes. Sixteen status post Le Fort III osteotomy Apert's and Crouzon's patients with pre- and postoperative lateral cephalograms were evaluated. The cephalograms were traced, and linear and angular measurements were obtained. Pre- and postoperative data were compared using a Student's paired t-test. The correlation between changes in the nasopharyngeal airway and its surrounding skeletal structures was evaluated. Finally, the study subjects were divided into two groups--Apert's and Crouzon's--and preoperative measurements from each group were compared with normal data by a Student's paired t-test. Significant improvement in the nasopharyngeal airway followed Le Fort III advancement, with changes in both hard and soft tissues. There was no change in the pharyngeal airway, even though a decrease might be predicted because of the clockwise rotation of the mandible. The morphology of the impairment in the nasopharyngeal airway differed between Apert's and Crouzon's syndrome individuals. Our results suggest that, for the purpose of airway improvement, the midface should be mainly advanced in the Crouzon's syndrome individual, whereas the downward component of the movement should be predominant in the Apert's syndrome individual.

Acrocephalosyndactylia↗
PubMed1995

Costochondral reconstruction of mandibular condyles in nongrowing primates.

The aim of this study was to develop a reproducible model in nongrowing animals to document morphological and histological changes after costochondral reconstruction of the mandibular condyle. Seven adult monkeys underwent a unilateral condylectomy followed by costochondral reconstruction. Dimensional changes of the thorax and reconstructed ramus-condyle unit were documented by in situ and radiographic analysis. Morphological and histological analysis were completed after removal at 4 (n = 2), 8 (n = 2), and 12 months (n = 3). In situ measurements demonstrated no dimensional changes of the thorax, but the reconstructed ramus-condyle unit decreased in height an average of 3.2 +/- 1.4 mm. The original graft remained unchanged morphologically, but new bone and cartilage progressively encompassed it, creating a form similar to the native condyle. Histologically, the transplanted cartilage remained unchanged. However, the articulating surface progressively took the appearance of the native condyle. Results of this study indicated that, in nongrowing animals, the reconstructed ramus-condyle unit decreases in height slightly but remodels to a size and shape morphologically and histologically similar to the native condyle.

Animals↗
PubMed1995

Guided bone regeneration in calvarial bone defects using polytetrafluoroethylene membranes.

Guided bone regeneration is defined as controlled stimulation of new bone formation in a bony defect, either by osteogenesis, osteoinduction, or osteoconduction, re-establishing both structural and functional characteristics. Bony defects may be found as a result of congenital anomalies, trauma, neoplasms, or infectious conditions. Such conditions are often associated with severe functional and esthetic problems. Corrective treatment is often complicated by limitations in tissue adaptations. The aim of the investigation was to compare histologically the amount of bone formed in an experimentally created parietal bone defect protected with one or two polytetrafluoroethylene membranes with a contralateral control defect. A bony defect was created bilaterally in the parietal bone lateral to the sagittal suture in 29 6-month-old male Wistar rats. The animals were divided into two groups: (1) In the double membrane group (n = 9), the left experimental bone defect was protected by an outer polytetrafluoroethylene membrane under the periosteum and parietal muscles and an inner membrane between the dura mater and the parietal bone. (2) In the single membrane group (n = 20), only the outer membrane was placed. The right defect was not covered with any membrane and served as control. The animals were killed after 30 days. None of the control defects demonstrated complete or partial bone regeneration. In the single membrane group, the experimental site did not regenerate in 15 animals, partially in four, and completely in one. In the double membrane group, six of the experimental defects had complete closure with bone, two had partial closure, and one no closure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Some aspects of bone formation and remodeling pertinent to craniofacial development and reconstructive treatment.

Bone formation, modeling, and remodeling occur as physiologic developmental growth or healing processes. Bone formation and turnover is an ongoing process from early organogenesis to the end of life. The assumption can be made that all elements for osteogenesis and resorption are present at any time and can be activated given an appropriate environment. Bone is a dynamic tissue that is readily influenced by its environment. Recognition of this fact is essential in the treatment of dental malocclusions and in reconstruction of jaw, facial, and skull deformities. Examples of experimental studies on various environments for bone formation and clinical application of the experimental findings are here related to treatment of alveolar clefts, bony contour deficiencies, midface hypoplasia, skull bone defects, and traumatically or congenitally underdeveloped, rudimentary, or missing mandibular condyle/ramus units.

Animals↗
PubMed1993

Placement of an endosseous implant in a growing child with ectodermal dysplasia.

This article reports placement of a single mandibular endosseous implant in a 5-year-old patient with hypohidrotic ectodermal dysplasia and oligodontia. This congenital anomaly does not appear to retard healing and the osseointegration remains after 5 1/2 years of loading. Surgical, prosthodontic, and growth and development considerations are presented.

Anodontia↗
PubMed1992

Surgically assisted rapid maxillary expansion in adults.

Twelve adults with maxillary width discrepancy of greater than 5 mm were treated by surgically assisted rapid maxillary expansion. The procedure consisted of bilateral zygomatic buttress and midpalatal osteotomies combined with the use of a tooth-borne orthopedic device postoperatively. Mean palatal expansion of 7.5 mm (range of 6 to 13 mm), measured in the first molar region, was achieved within 3 weeks in all patients. Expansion remained stable during the 12-month study period, with a mean relapse for the entire group of 0.88 +/- 0.48 mm. Morbidity was limited to mild postoperative discomfort. The results of this preliminary study indicated that surgically assisted rapid maxillary expansion is a safe, simple, and reliable procedure for achieving a permanent increase in skeletal maxillary width in adults. Further study is necessary to document the three-dimensional movements of the maxillary segments and long-term stability of the skeletal and dental changes.

Adolescent↗
PubMed1989

Effect of Le Fort III osteotomy on mandibular growth in patients with Crouzon and Apert syndromes.

Midface advancement by Le Fort III osteotomy is a common procedure in craniofacial surgery. However, little data exist concerning the effect of midface advancement on mandibular growth. This is a retrospective study of 38 patients from two craniofacial centers who had Le Fort III osteotomy. The aims of this investigation were to document the size and shape of the mandible in Crouzon and Apert syndromes and to determine the effect on these parameters of downward and forward movement of the midface. The syndrome patients had increased gonial angle, increased MP-SN, increased ramus height, and increased ratio of ramus height to body length when compared with normal standards. Patients operated during growth and those operated when growth was completed had similar mandibular size and shape indicating that Le Fort III osteotomy had no measurable effect on these parameters. Inclination of the mandible to the anterior cranial base was increased by the operation and remained unchanged during the follow-up period. The results of this study indicate that the size and morphology of the mandible are similar in Crouzon and Apert syndromes. The pattern of growth is more vertical in the syndrome patients than in normals. Le Fort III osteotomy in growing children does not result in altered mandibular size and shape despite backward rotation of the mandible as a result of midface advancement.

Acrocephalosyndactylia↗