Biomedical subjects

Ariane Hohoff

Publications and source records attributed to Ariane Hohoff.

At least 19 recordsLinked to original sources

PubMed2007

The influence of lead thyroid collars on cephalometric landmark identification.

OBJECTIVE: To investigate whether the application of thyroid collars (TCs) affects cephalometric landmark identification. STUDY DESIGN: A randomized and observer-blinded diagnostic study with head films taken from 2 groups was undertaken, with 1 group wearing TCs during radiography (n = 100) and 1 group not wearing TCs (n = 100). The interobserver reproducibility of 15 landmarks was evaluated using 1-way analysis of variance and independent samples t test to compare the groups. RESULTS: The total mean error radius of the non-TC group (1.28 +/- 1.47 mm) was smaller (P < or = .001) than that of the TC group (1.57 +/- 1.58 mm). Three landmarks located on the hyoid bone and on the second and third cervical vertebrae were identified as the main confounding factors. CONCLUSIONS: Personal lead shielding of the thyroid gland affects landmark identification, but the overall clinical effect is negligible. Thyroid collars should be routinely applied during cephalometric radiography if cephalometric analyses are limited to structures above the second cervical vertebra.

Analysis of Variance↗

PubMed2005

Palatal development of preterm and low birthweight infants compared to term infants -- What do we know? Part 3: discussion and conclusion.

BACKGROUND: It has been hypothesized that prematurity and adjunctive neonatal care is 'a priori' a risk for disturbances of palatal and orofacial development which increases the need for later orthodontic or orthognathic treatment. As results on late consequences of prematurity are consistently contradictory, the necessity exists for a fundamental analysis of existing methodologies, confounding factors, and outcomes of studies on palatal development in preterm and low birthweight infants. METHOD: A search of the literature was conducted based on Cochrane search strategies including sources in English, German, and French. Original data were recalculated from studies which primarily dealt with both preterm and term infants. The extracted data, especially those from non-English paper sources, were provided unfiltered in tables for comparison (Parts 1 and 2). RESULTS: Morphology assessment of the infant palate is subject to non-standardized visual and metrical measurements. Most methodologies are inadequate for measuring a three-dimensional shape. Several confounding factors were identified as causes contributing to disturbances of palatal and orofacial development. CONCLUSION: Taking into account the abovementioned shortcomings, the following conclusions may be drawn for practitioners and prospective investigators of clinical studies. 1) The lack of uniformity in the anatomical nomenclature of the infant's palate underlines the need for a uniform definition. 2) Metrically, non-intubated preterm infants do not exhibit different palatal width or height compared to matched term infants up to the corrected age of three months. Beyond that age, no data on the subject are currently available. 3) Oral intubation does not invariably alter palatal morphology of preterm and low birthweight infants. 4) The findings on palatal grooving, height, and asymmetry as a consequence of orotracheal intubation up to the age of 11 years are inconsistent. 5) Metrically, the palates of orally intubated infants remain narrower posteriorly, beginning at the second deciduous molar, until the age of 11 years. Beyond that age, no data on the subject are currently available. 6) There is a definite need for further, especially metrical, longitudinal and controlled trials on palatal morphology of preterm and low birthweight infants with reliable measuring techniques. 7) None of the raised confounding factors for developmental disturbances may be excluded until evident results are presented. Thus, early orthodontic and logopedic control of formerly premature infants is recommended up to the late mixed dentition stage.

Humans↗

PubMed2005

Palatal development of preterm and low birthweight infants compared to term infants - What do we know? Part 1: The palate of the term newborn.

BACKGROUND: The evidence on prematurity as 'a priori' a risk for palatal disturbances that increase the need for orthodontic or orthognathic treatment is still weak. Further well-designed clinical studies are needed. The objective of this review is to provide a fundamental analysis of methodologies, confounding factors, and outcomes of studies on palatal development. One focus of this review is the analysis of studies on the palate of the term newborn, since knowing what is 'normal' is a precondition of being able to assess abnormalities. METHODS: A search profile based on Cochrane search strategies applied to 10 medical databases was used to identify existing studies. Articles, mainly those published before 1960, were identified from hand searches in textbooks, encyclopedias, reference lists and bibliographies. Sources in English, German, and French of more than a century were included. Data for term infants were recalculated if particular information about weight, length, or maturity was given. The extracted values, especially those from non-English paper sources, were provided unfiltered for comparison. RESULTS: The search strategy yielded 182 articles, of which 155 articles remained for final analysis. Morphology of the term newborn's palate was of great interest in the first half of the last century. Two general methodologies were used to assess palatal morphology: visual and metrical descriptions. Most of the studies on term infants suffer from lack of reliability tests. The groove system was recognized as the distinctive feature of the infant palate. The shape of the palate of the term infant may vary considerably, both visually and metrically. Gender, race, mode of delivery, and nasal deformities were identified as causes contributing to altered palatal morphology. Until today, anatomical features of the newborn's palate are subject to a non-uniform nomenclature. CONCLUSION: Today's knowledge of a newborn's 'normal' palatal morphology is based on non-standardized and limited methodologies for measuring a three-dimensional shape. This shortcoming increases bias and is the reason for contradictory research results, especially if pathologic conditions like syndromes or prematurity are involved. Adequate measurement techniques are needed and the 'normal palatal morphology' should be defined prior to new clinical studies on palatal development.

Humans↗

PubMed2005

Palatal development of preterm and low birthweight infants compared to term infants - What do we know? Part 2: The palate of the preterm/low birthweight infant.

BACKGROUND: Well-designed clinical studies on the palatal development in preterm and low birthweight infants are desirable because the literature is characterized by contradictory results. It could be shown that knowledge about 'normal' palatal development is still weak as well (Part 1). The objective of this review is therefore to contribute a fundamental analysis of methodologies, confounding factors, and outcomes of studies on palatal development in preterm and low birthweight infants. METHODS: An electronic literature search as well as hand searches were performed based on Cochrane search strategies including sources of more than a century in English, German, and French. Original data were recalculated from studies which primarily dealt with both preterm and term infants. The extracted data, especially those from non-English paper sources, were provided unfiltered for comparison. RESULTS: Seventy-eight out of 155 included articles were analyzed for palatal morphology of preterm infants. Intubation, feeding tubes, feeding mode, tube characteristics, restriction of oral functions, kind of diet, cranial form and birthweight were seen as causes contributing to altered palatal morphology. Changes associated with intubation concern length, depth, width, asymmetry, crossbite, and contour of the palate. The phenomenon 'grooving' has also been described as a complication associated with oral intubation. However, this phenomenon suffers from lack of a clear-cut definition. Head flattening, pressure from the oral tube, pathologic or impaired tongue function, and broadening of the alveolar ridges adjacent to the tube have been raised as causes of 'grooving'. Metrically, the palates of intubated preterm infants remain narrower, which has been examined up to the age of the late mixed dentition. CONCLUSION: There is no evidence that would justify the exclusion of any of the raised causes contributing to palatal alteration. Thus, early orthodontic and logopedic control of formerly orally intubated preterm infants is recommended, as opposed to non-intubated infants. From the orthodontic point of view, nasal intubation should be favored. The role that palatal protection plates and pressure-dispersing pads for the head have in palatal development remains unclear.

Humans↗

PubMed2005

Objective growth monitoring of the maxilla in full term infants.

OBJECTIVE: To develop a non-invasive method for longitudinal maxillary volume measurements and to provide first normative data. DESIGN: Thirty-four healthy infants served as a gold standard for a growing population sample. Alginate impressions were taken of the upper jaw within the first week after birth, and consecutively at different stages of development. The plaster casts were digitised by an optical scanner generating a high resolution polygon mesh of each object. The digital models were aligned to a reference coordinate system with an iterative, landmark-independent procedure. Biometric linear and volume measurements were obtained by using feature-dependent calculations independent of landmark placements. Intra-investigator reproducibility was tested by repeated alignments and measurements of 30 randomly selected casts. To assess the effect of mesh resolution, the reproducibility test was repeated with low resolution models. The method was proved to be valid on the defined gold standard consisting of 96 consecutive edentulous casts. RESULTS: Feature-dependent, linear distances are less error prone (0.56-2.66%) compared to subjectively determined measurements (0.88-3.65%). The same applies to feature-dependent volume calculations (4.34%) compared to subjectively determined volumes (4.95%). Mesh resolution shows an effect (p<or=0.001) only on two linear measurements: palatal depth and palatal length. Growth of the individuals in the population sample was evidently confirmed by the maxillary volume measurements (asymptotic pattern) and by comparisons of head circumference (proportional pattern). CONCLUSION: The described method is non-invasive, precise and without any risk for the infant. Maxillary volume calculation could serve as an important biometric measurement for bone growth evaluation.

Biometry↗

PubMed2005

Potential and limitations of cephalometric analysis of maxillofacial bone movement in the case of LeFort III-distraction.

BACKGROUND AND METHOD: The treatment of craniofacial deformities by means of distraction osteogenesis has become an established therapeutic procedure. Evaluation of the success of an operation is usually carried out via conventional cephalometry. Conventional forms of analysis seem problematic due to surgically-induced changes in the skull base. In this study we investigated the movement of the midface in the presence of a syndromerelated surgical indication employing two different types of analysis, namely those of Ricketts and Delaire. RESULTS: It seems that neither procedure is suitable for determining this type of bone movement conclusively. Comparing the two, the Delaire analysis possessed greater informative value in view of the altered geometry, and a combination of both procedures made more exact determination possible of the final position achieved.

Adolescent↗

PubMed2005

A subjective comparison of two lingual bracket systems.

The purpose of this prospective, longitudinal study was to compare the influence of two lingual bracket systems on subjective oral comfort, speech, mastication and oral hygiene. Forty-two native speakers of standard German (32 females, 10 males; mean age 27.1 years, standard deviation 12.2) were enrolled and completed a standardized questionnaire directly before insertion of lingual brackets (T0), within 24 hours of bond-up (T1) and 3 months (+/- 1 week) later (T2). Eighteen of the patients were treated with prefabricated brackets (Ormco, seventh generation) (PB group) and 24 with customized brackets (Incognito) (CB group). While no significant intergroup differences were recorded at any of the times with respect to tongue position, conversation pattern, swallowing or oral hygiene, the CB group experienced significantly fewer tongue space restrictions, speech disturbances and impairments in chewing and biting than the PB group at T1 and T2. At T2, pressure sores, reddening or lesions to the tongue were recorded significantly less often in the CB group than in the PB group. This enhanced patient comfort in the CB group was attributed to the smaller dimensions of the customized brackets. This aspect could play a role in attracting more patients to lingual orthodontics in the future. Information given to the patient on the duration and extent of the restrictions associated with lingual orthodontics must be differentiated according to the bracket system used.

Adult↗

PubMed2004

On the three-dimensional physiological position of the temporomandibular joint.

Despite intensive research regarding the position of the temporomandibular joint, only few evidence-based facts are known about a three-dimensional physiological condyle-fossa relationship. The aim of this systematic literature review was therefore to summarize the existing literature regarding the condyle position and to draw conclusions about a standardized three-dimensional condyle position. An extended search profile based on the search strategy of the Cochrane Oral Health Group and applied to twelve medical databases was used to identify existing studies. Articles which were not electronically accessible (mainly those published before 1960) were identified from reference lists and bibliographies. These publications were assessed independently by two clinicians with reference to points based on specified criteria. The interexaminer agreement was assessed on the basis of the kappa coefficient.1903 articles published in the period 1899-2001 and relating to condyle position were identified. These studies showed a pronounced variability in their methodological approaches, with only 49 of them meeting the inclusion criteria. The interexaminer agreement yielded a kappa-value of 0.92. Although numerous studies used three-dimensional data, no physiological three-dimensional condyle position was determined. The most frequent analytic method was two-dimensional projection of the temporomandibular joint onto a subjectively selected sagittal plane. This evaluation method revealed a noticeable shift over time in condyle position from posterior to anterior, suggesting a clear-cut publication bias. Publications with the highest evidence level favored no specific position (p > 0.05). Simplification of the three-dimensional structure of the temporomandibular joint to a two-dimensional projection is questionable for therapeutic positioning of the condyle in relation to the fossa.

Databases, Factual↗

PubMed2004

Accuracy of third-order bends of nickel-titanium wires and the effect of high and low pressure during memorizing heat treatment.

This study evaluated the accuracy of third-order bends of nickel-titanium wires and determined the effect of high and low pressure for maintaining the wire shape during memorizing heat treatment. A computer-aided bending machine was used to incorporate 200 randomly determined torsional angles between 0 degrees and 60 degrees into 30 linear 0.016 x 0.022-in NeoSentalloy F80 (GAC International, Central Islip, NY) wires. The torsional bendings were randomized into 2 groups. Bends assigned to group 1 (n = 100) received heat treatment of 1.6 MPa (16 bar) pressure, and bends assigned to group 2 (n = 100) received heat treatment of 50 MPa (500 bar) pressure. Cross-sectional cuts from the bent wires were prepared by using standard metallurgical techniques, and the torsional angles were analyzed under computer control. The results of our study show that third-order bends </= 30 degrees can be made with adequate clinical accuracy with an error of 1.89 degrees +/- 1.75 degrees (0 degrees to 10 degrees ) and 3.57 degrees +/- 1.57 degrees (20 degrees to 30 degrees ), irrespective of the pressure applied. With bends > 30 degrees but </= 40 degrees , the method with the higher pressure offers fundamentally greater precision than that with the lower pressure. With torque bends > 40 degrees , the bending error with both methods is clinically unacceptable. In addition to the variability in the dimension and composition of nickel-titanium wires, the scale of the incorporated plastic deformations makes a substantial contribution to the bending error. As far as permitted by the clinical situation, then, the bend should be distributed over the maximum possible wire length. Third-order bends in the first rectangular pseudoelastic nickel-titanium wires represent an efficient means of effecting torque at an early stage. This individualization allows the full therapeutic potential of these archwires to be exploited right from the initial phase of treatment.

Dental Alloys↗

PubMed2004

Comparison of the effect on oral discomfort of two positioning techniques with lingual brackets.

Using a standardized questionnaire, 41 patients (12 men, 29 women; mean age 31.5 +/- 12.1 years) were interviewed prospectively on their subjective oral comfort, various oral functions, and professional qualification before indirect application of lingual brackets (T0), within 24 h of application (T1), and three months later (+/- 1 week) (T2). In 22 of the 41 patients, the brackets were positioned with the Bonding with Equalized Specific Thickness (BEST) technique (BEST group) and in 19 patients by the Transfer Optimized Positioning (TOP) method (TOP group). Despite positive adaptation, the patients in both groups still reported a significant deficiency in tongue space at T2 as well as significantly more frequent lesions to the tongue. The BEST group was affected significantly more often by these problems than the TOP group. At T2, the tongue position was also rated as changed significantly more often in the BEST group than in the TOP group. Although the BEST positioning technique leads to greater impairments in oral comfort than the TOP technique, it offers the orthodontist the advantage of less bending input. In both techniques, there is a need for detailed briefing of patients about the extent and duration of impairments induced by lingual brackets.

Adult↗

PubMed2004

Nonlinear behavior of search strategies for identifying relevant orthodontic articles.

The communication process with electronic literature databases permitting a freetext search is prone in part to nonlinear, chaotic behavior. Even very minor changes in the initial conditions (search query) have a dramatic impact on the concluding event (search outcome). This statement has been verified with reference to alterations to the term "orthodontic" in search strategies of published systematic reviews. The results showed that a variation in one letter led to an average of 152 papers, 81% of them of orthodontic relevance, failing to be localized. Yet, the opposite effect, the elimination of papers (-418), was also observed, confirming the underlying nonlinear pattern. Search queries for orthodontic articles should invariably be equipped with the robust truncation "orthodon*." Truncation variants of key words should be used as a matter of principle to verify the outcome.

Databases, Bibliographic↗

PubMed2003

Evaluation of the parameters underlying the decision by adult patients to opt for lingual therapy: an international comparison.

BACKGROUND: The present study is the first instance of patients having been questioned on the criteria applied in their decision for therapy with lingual brackets and on the sources of information available to them within the framework of an international comparison prior to the start of therapy by means of a standardized questionnaire. PATIENTS AND METHOD: 68 patients (19 male, 49 female; mean age 32.4 years, range 19.8 to 60.0 years, SD 9.7) were interviewed. RESULTS: Therapy with lingual brackets was more important to the patients in the present study for professional than for private reasons: The further the patients were from the typical "braces age", the more important was treatment with an invisible appliance from the professional standpoint. The patients' educational level had no influence on the decision for a fixed lingual appliance. There was no significant difference between the German and the French patients in the decision-making criteria of adult patients and the sources of information available to them in the context of the lingual technique. CONCLUSION: The information available through the media on the lingual technique is inadequate in both countries.

Adult↗

PubMed2003

Interdisciplinary study of orthopedic and orthodontic findings in pre-school infants.

BACKGROUND AND AIM: The assessment of correlations between orthopedic and orthodontic data based on interdisciplinary studies is of scientific and practical interest in the differentiation of preventive diagnostic and therapeutic fields between orthodontics and orthopedics. In the published literature there are various studies analyzing the correlations between specific Angle classes and orthopedic parameters. Results of these studies indicate a potential correlation between scoliosis and Class II malocclusion as well as between weak body posture and Class II malocclusion. The aim of the present interdisciplinary study was to examine correlations between orthodontic and orthopedic findings in pre-school infants and to evaluate them with respect to preventive recommendations. PATIENTS AND METHOD: 59 pre-school infants (29 boys, 30 girls) aged 3.5-6.8 years (mean: 5.0 years) were enrolled in this study. A standardized orthodontic and orthopedic examination protocol was used. RESULTS: The orthodontic examination showed Angle class distributions comparable with those in non-selected groups (Class I: 63%, Class II: 32%, Class III: 5%). The orthopedic examination revealed pathologic findings in 52% of the subjects, with statistically significant correlations between scoliosis and Class II malocclusion (p = 0.033) and between weak body posture and Class II malocclusion (p = 0.028). CONCLUSION: It can be concluded from the results that the orthodontic finding of Angle Class II in pre-school infants should induce prophylactic screening. The orthodontist could then not only initiate early orthodontic treatment to prevent incisor trauma in patients with extreme overjet, but could also take account of potential orthopedic malformations on a preventive interdisciplinary basis in pre-school infants with Class II malocclusions.

Child↗

PubMed2003

Oral comfort, function and hygiene in patients with lingual brackets. A prospective longitudinal study.

BACKGROUND: Oral comfort, speech, mastication and swallowing, as well as oral hygiene were to be evaluated in a prospective longitudinal study before and after insertion of lingual brackets. PATIENTS AND METHOD: 22 patients (five male, 17 female, mean age 34.7 years, SD 10.4) were enrolled in the study and filled in a standardized questionnaire directly before placement of lingual brackets (T0), within 24 hours thereafter (T1), and 3 months (+/- 1 week) later (T2). At both T1 and T2, treatment was confined to the upper arch. RESULTS: In comparison with T0, significantly poorer results were recorded at T2 for the parameters "restriction of the tongue space", "lesions to the tongue", "tongue position", "subjective and semiobjective rating of articulation", "chewing", "biting" and "oral hygiene", although significant improvements, i.e. adaptations, had been recorded from T1 to T2 with the exception of the parameters "tongue space", "tongue position", "chewing", "biting" and "oral hygiene". At none of the registration timepoints was fluid intake impaired by the lingual brackets. CONCLUSION: The results of the present study suggest that detailed briefing on the extent and duration of potential impairments in oral comfort, functions and hygiene is advisable prior to the insertion of lingual brackets.

Adult↗

PubMed2003

Comparison of 3 bonded lingual appliances by auditive analysis and subjective assessment.

The aim of this prospective study was to compare for the first time the influences of lingual appliances of different dimensions on sound performance and oral comfort. The study group comprised 12 subjects (10 women, 2 men; mean age, 33.96 years). Their sound production was recorded by means of a digital audio tape recorder before, 10 minutes after, and 24 hours after placement of the different appliances for semiobjective assessment by 3 blinded speech professionals. This was followed by supplementary subjective ratings of sound performance and oral comfort by the patients. All lingual appliances induced significant impairment in sound performance and oral comfort. However, they varied significantly with respect to the degree of impairment. The smaller the appliance, the less pronounced the impairments it induced. The smallest changes were induced by a bonded canine-to-canine retainer, followed by customized lingual brackets and prefabricated lingual brackets. By using lower-profile customized brackets, the orthodontist can significantly enhance patient comfort and significantly reduce impairments of sound performance in comparison with prefabricated brackets with larger dimensions. Before placing a lingual appliance, however, patients should be briefed on possible effects such as impaired sound production and decreased oral comfort.

Adult↗

PubMed2003

Effects of a mechanical interdental cleaning device on oral hygiene in patients with lingual brackets.

This study was aimed at determining the influence of a battery-operated interdental cleaning device (icd) (WaterPik Flosser) on the oral hygiene of 32 female right-handed patients (mean age 25.9 years) with lingual brackets in the upper (n = 29) and or in the lower arch (n = 25). Approximal plaque index (API) and bleeding on probing (BOP) were recorded at the lingual surfaces by a single blinded examiner before application (t0), on average 38.6 days after (t1), and again on average 46.0 days after (t2) the application of the icd. The patients used the icd once a day in the second and fourth quadrants only (icdq). In all quadrants (icdq and non-icd quadrants [n-icdq]), oral hygiene was performed with a manual toothbrush. Of the patients enrolled in the study, 96.9% found the icd subjectively very helpful to moderately helpful for cleaning their teeth and 65.6% had the subjective impression that their teeth were cleaner with the appliance. Despite those positive subjective assessments, an objective comparison of the icdqs with the n-icdqs revealed no statistically significant differences in the mean changes in API and BOP from t0 to t1, from t0 to t2, or from t1 to t2. Because there were spectacular improvements in API in all quadrants, the improvements could be interpreted as an outcome of the instruction and motivation given to the patients, the increasing awareness of oral hygiene, and the greater skill in using the toothbrush in the course of time.

Adolescent↗

PubMed2003

Speech performance in lingual orthodontic patients measured by sonagraphy and auditive analysis.

Esthetically appealing, externally invisible, lingually applied orthodontic brackets are in increasing demand. Because the brackets are placed lingually, however, they appear to cause some problems with respect to speech. This study is the first to present a prospective evaluation of the articulation of 23 patients with lingual brackets by means of an innovative combination of test methods. An acoustic, objective evaluation of articulation measured by digital sonagraphy was related to a semiobjective auditive evaluation by 10 speech professionals, to a semiobjective auditive evaluation by close contacts of the patients, and to a subjective auditive evaluation by the patients themselves, the latter 2 using standardized questionnaires. The tests were performed before (T1), within 24 hours after (T2), and 3 months (+/- 1 week) after (T3) the start of therapy. In comparison with the initial findings, a significant deterioration in articulation was recorded with all test methods at T2 and T3. Using a new combination of methods, our investigations show the need for detailed briefing of patients about the extent and duration of changes in speech resulting from lingual brackets.

Adult↗

PubMed2003

Validity of a three-dimensional public-domain system for contemporary endodontic research.

The purpose of this study was to evaluate the limits and benefits of a visualization system based on public-domain software for contemporary three-dimensional (3-D) endodontic research purposes. Three-dimensional bio-models of six human teeth and of one bone-implant specimen were generated using cross-sectional imaging. To evaluate the overall performance in processing large data sets and in reproducing accurate 3-D morphology, slices with a thickness varying from 100 microm to 10 microm were cut. Auto-outlining and segmenting techniques were tested. The 3-D bio-models represented in accurate detail the different morphological aspects of the specimen. Voxel volumes of 0.116 x 10(-5) mm3 could be realized and were only restricted by the computer hardware limitations. The system is not limited to dental hard tissues. Hypomineralized material and soft tissues as well as bone- and allogeneic-implant material could be visualized. The method presented is valid and meets current requirements applying to endodontic research. The broad-based use of high-quality, public-domain software and the resulting exchange of experience help to manage resources and may contribute to enhancing the in-process quality of research.

Anatomy, Cross-Sectional↗