Biomedical subjects

Ulrike Ehmer

Publications and source records attributed to Ulrike Ehmer.

17 recordsLinked to original sources

PubMed2006

In-vitro investigations on suitability of light-cured resins for interocclusal splints: part I: mechanical properties.

OBJECTIVE: It was the aim of the present study to investigate the material properties of different resins and their suitability for the fabrication of occlusal and intermaxillary splints. MATERIAL AND METHOD: We subjected auto-polymerized resins (Palapress, Orthocryl, Steady-Resin M) and light-polymerized resins (Acrylight, Primosplint, Triad TranSheet Colorless and Pink) to investigation. The Targis Power light oven was used to polymerize the light-cured resins. After the auto-polymerized resins had been mixed by hand and filled into the forms, they were polymerized for 15 minutes in a high-pressure polymerization machine (Palamat) at 2 bar. The parameters examined were flexural strength, water adsorption, and polymerization shrinkage. Tests carried out according to DIN EN ISO 1567 served to determine flexural strength, flexural modulus, and water adsorption. Polymerization shrinkage was determined via the buoyancy test. RESULTS: The resins' flexural strength ranged from 60 to 101 MPa. Flexural moduli lay between 1.3 and 5.3 GPa. The water adsorption noted in light-cured resins amounted to 2.1-4.6 mass percent. Palapress and Steady-Resin displayed the lowest water adsorption with 2.0 mass percent. The light-polymerized resins revealed significantly less shrinkage (p < 0.05) than the autopolymerized resins tested in this study. CONCLUSION: Our results demonstrate that the light-cured resins-with the exception of Acrylight -easily match and even exceed the material properties of the cold-polymerized resins regarding flexural strength, flexural modulus, water adsorption and polymerization shrinkage. The light-cured resins examined thus seem suitable for use as splint material.

Absorption↗

PubMed2006

In-vitro investigation on suitability of light-cured resins for interocclusal splints : part II: surface hardness.

OBJECTIVE: The aim of the present study was to determine the surface hardness of light- and auto-cured resins for the fabrication of occlusal splints employing Vickers hardness measurements. MATERIALS AND METHOD: In this study we used three auto-polymerized resins (Palapress, Orthocryl, Steady-Resin M) and four light-polymerized resins (Acrylight, Primosplint, Triad Tran- Sheet Colorless and Triad TranSheet Pink). The Vickers hardness measurement was carried out by means of a universal Durimet indenter applying a test load of 50 g for 30 seconds. The light-cured resins were polymerized in a Tagris Power light oven for 10 and 15 minutes each. Three separate test series were carried out (the hardness of plates under optimal conditions and of occlusal splints was measured, and the curing of light-polymerizing materials in layers of varying depth was evaluated). Data underwent statistical analysis via ANOVA and the Scheffé test. RESULTS: The microhardness determined in each case amounted to values between 10.4 HV 0.5 and 39.3 HV 0.5. The Vickers hardness determined for the plates that had been produced under optimal conditions demonstrated that their surface was significantly (p < 0.05) harder than that of cylinders and splints. The hardness values of the light-cured material Triad TranSheet Pink (39.3 HV 0.5) were significantly higher (p < 0.05) than those of all other resins. In all auto-polymerized resins, the surface hardness of the samples we examined (in the form of plates and splints) was significantly lower (p < 0.05) than that of the light-cured materials Triad TranSheet Pink and Colorless. CONCLUSION: The results we have obtained so far concerning surface hardness indicate that, in the fabrication of occlusal splints, light-cured resins may represent an alternative to auto-polymerizing materials.

Absorption↗

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

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

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↗

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↗

PubMed2002

A prospective randomized study of different retainer types.

BACKGROUND AND AIM: In recent years, fixed lingual retainers have been gaining importance in relapse prevention. The aim of this prospective, randomized study was to compare different types of fixed retainers used for stabilization of the lower anterior segment with respect to detachment rate, relapse, periodontal and oral hygiene problems, as well as subjective patient discomfort. PATIENTS AND METHOD: Two types of fixed, customized canine-to-canine retainers (attached to six teeth) with wire diameters of 0.0215" and 0.0195" as well as one type of prefabricated canine-and-canine retainer (bonded to two teeth) were investigated in a total of 103 patients. Some retainers were inserted under dry field conditions using a rubber dam, and the others under relatively dry conditions using cotton rolls. In addition, two types of composite, Heliosit and Concise, were compared. RESULTS: The canine-and-canine retainer displayed an 18% detachment rate, a value significantly lower than the 29% determined for the 0.0195" canine-to-canine retainers. The 0.0215" canine-to-canine retainer had the highest detachment rate (53%). The 37% detachment rate with dry field bonding was slightly higher than the 32% with relatively dry field bonding. Comparison of the composites showed a significantly higher detachment rate for Heliosit (73%) than for Concise (27%). Plaque accumulation increased with all retainer types in the course of the study, but with no significant inter-group differences. Tooth position with canine-to-canine retainers showed a good degree of stability. The canine-and-canine retainer induced frequent relapse of incisors not bonded to the retainer. In view of their higher rate of subjective discomfort, canine-and-canine retainers were given a significantly poorer rating than their canine-to-canine counterparts.

Adolescent↗

PubMed2002

Public domain computer-aided surgery (CAS) in orthodontic and maxillofacial surgery.

BACKGROUND: Computer-aided virtual three-dimensional (3D) surgical simulation assists the necessary visual understanding of complex pathological situations but has so far been dependent on expensive hardware and software. METHOD: For the first time a non-commercial, user-orientated application for orthognathic and craniofacial surgical simulation has been introduced, based on freeware NIH Image 1.62 provided by the National Institute of Mental Health (NIMH). Use and limitations are demonstrated here by the example of hypertelorism surgery. The osteotomy lines and the amount of resection for outward positioning of the orbits were determined by the surgeon on a workstation using CT data. Possible movement patterns of the osteotomy fragments were rotations, sagittal and transversal movements or combinations of these. The program then allows the calculation of anatomical distances on the screen in a 1:1 relation. Normative values according to age and pathological anatomy determine the degree of displacement. The program calculates the new position of the osteotomy fragments and transfers the data of the segment movement to the original CT data. RESULTS: 3D visualization of bone and soft tissue contours have been produced with an acceptable quality on a workstation for the demonstration and visual understanding of the surgical plan. Evaluation of a postoperative CT showed that the amount of movement and size of bone resection in the simulation was slightly overestimated rather than underestimated. This was also dependent on the complexity of the pathological anatomy and on how experienced the surgeon was. CONCLUSION: The use of 3D simulation programs allows a better understanding of the pathological anatomy in all dimensions, and in many cases enables limitations to be recognized in advance. The public domain program makes a major contribution to the quality of orthognathic and craniofacial surgical planning through cost-free usability, and supports continuous development and exchange of experience.

Cephalometry↗

PubMed2002

Optimizing presurgical orthodontic planning by means of the transverse coordinate simulation system (TCSS).

INTRODUCTION: When planning bilateral sagittal split osteotomies according to Obwegeser and Dal Pont, inaccuracies in the presurgical prediction of the transverse osteotomy gaps may occur. This is due to limitations of plaster models when simulating surgery on an articulator. AIM: This paper demonstrates the transverse coordinate simulation system which allows presurgical prediction of the transverse discrepancy between the tooth bearing and the proximal segment after displacement, thus minimizing uncertainty for the surgeon. METHOD: Diagnostic landmarks (taken from lateral and frontal cephalograms) and clinical data describing mandibular dimensions are transferred to a two-dimensional coordinate diagram. A mandibular model is then constructed using the anterior arch form, the temporomandibular joint distance and the prospective incision pattern. RESULT: Movements in the horizontal plane and displacement of the three segments (two condylar and one mandibular arch segment) can be simulated and measured. CONCLUSION: Transverse coordinate simulation system effectively increases the accuracy of presurgical planning without additional CT data or three-dimensional jaw models. This technique may decrease the number of additional surgical manoeuvres resulting from unexpectedly wide transverse discrepancies at the osteotomy site, which often increase surgery time, necessitate additional bone grafting, and entail the risk of healing disturbances and of malrotation or dislocation of the condyle.

Cephalometry↗