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Biomedical subjects

G Göz

Publications and source records attributed to G Göz.

At least 19 recordsLinked to original sources
PubMed2002

[3-dimensional image acquisition for analysis of primary, cleft-induced facial deformity with an optoelectronic surface scanner].

BACKGROUND: Anthropometric analysis of the face has been performed with direct facial measurement and photogrammetry. Both methods have disadvantages. The aim of our investigation was to create a three-dimensional image of the primary cleft nasal deformity with a video scanner and to carry out linear measurements. MATERIAL AND METHODS: Facial plaster casts of 19 patients with uni- and bilateral cleft lip and palate before primary lip repair were scanned with digital surface photogrammetry DSP 400. The width of the nose and of the nostril floor, the distance of the alar bases, the length of the ala, and the nasal tip protrusion were measured. RESULTS: Imaging was possible without problems in all models. Direct measurements of the model correlated well with the results of the three-dimensional image. Significant dimensional differences of the nasal parameters examined were noted, depending on the cleft type. DISCUSSION: A video-supported surface scanner allowed immediate three-dimensional imaging of the face. The computer software analyzed the generated surface exactly. The data measured with the presented system resembled other previously published results.

Casts, Surgical↗
PubMed2001

Clinical application and effects of the Forsus spring. A study of a new Herbst hybrid.

BACKGROUND: The best known of the fixed functional appliances are the Herbst appliance and the Jasper Jumper. The Forsus spring is a new development which has been tested in a clinical study to establish when it can be used and to compare it with its predecessors. PATIENTS AND METHOD: The Forsus spring was used over a period of 4 months to treat 13 patients with an average age of 14.2 years with Class II malocclusion. RESULTS: Evaluation of the lateral cephalograms showed that dental effects accounted for 66% of the sagittal correction. The sagittal occlusal relations were improved by approximately 3/4 of a cusp width to the mesial on both the right and left side as a result of distal movement of the upper molars and mesial movement of the lower molars. Retrusion of the upper and protrusion of the lower incisors reduced the overjet by 4.6 mm. Intrusion and protrusion of the lower incisors reduced the overbite by 1.2 mm. The occlusal plane was rotated by 4.2 degrees in clockwise direction as a result of intruding the lower incisors and the upper molars. The maxillary and mandibular arches were expanded at the front and rear during treatment.--Evaluation of a questionnaire filled in by the patients after 2 months of treatment showed that approximately half of them had experienced difficulties in brushing their teeth. The main problem, however, was the restriction experienced in the ability to yawn. Overall, two thirds of the adolescents found the Forsus spring better than the appliance previously used to correct their Class II malocclusion, such as headgear, activator or Class II elastics. CONCLUSION: The Forsus spring has stood the test in clinical application. It is a good supplement to the Class II appliance systems already available.

Adolescent↗
PubMed2001

Fracture resistance of human incisors and premolars: morphological and patho-anatomical factors.

305 extracted human front teeth and premolars were investigated for their dynamic resistance to fracture. Morphological factors, such as the anatomical class of tooth and root lengths, and patho-anatomical factors, such as infractions, occlusal and cervical abrasions, composite and amalgam restorations and damage resulting from previous traumatic impacts, were taken into consideration. A comparison of stability after a defined impact stress showed that maxillary canines and premolars had the highest resistance to fracture; this differs significantly from the resistance of maxillary and mandibular incisors. The root length correlates directly with fracture energy and therefore to stability. Composite restorations with an adhesive joint were found to increase the resistance of a tooth to fracture, but amalgam restorations had a weakening effect. Cervical wedge-shaped defects of the tooth cause considerable destabilization, but occlusal abrasion and infractions have only a moderate weakening influence. Previous traumatic stress reduces the resistance to fracture of a tooth by up to 85%. The fracture patterns generated were very similar to clinically observed tooth fractures, indicating the results to be clinically relevant.

Analysis of Variance↗
PubMed2000

Three-dimensional computer morphometry of the maxilla and face in infants with Pierre Robin sequence--a comparative study.

OBJECTIVE: To analyze the morphology of the maxillary crest in infants with Pierre Robin sequence using an anthropometric coordinate system and to compare the data with those of healthy infants. SETTING: The study was performed at a craniofacial center servicing a large geographic area. PARTICIPANTS: The study involved eight infants aged 1-28 days (average, 7 days) with an established diagnosis of Pierre Robin sequence and six healthy infants aged 1-43 days (average, 22 days). MAIN OUTCOME MEASURES: Physical models of the maxilla and face obtained by alginate replication were analyzed by computer morphometry yielding the three-dimensional topology of the maxillary crest. RESULTS: The maxillary crest of children with Pierre Robin sequence shows an increased inclination relative to the transverse plane (30 +/- 3.9 degrees) as compared with that of healthy infants (20 +/- 2.9 degrees). The maxillary crest of the patients is shortened in the sagittal direction by comparison with healthy controls. CONCLUSIONS: The increased inclination of the maxilla in infants with Pierre Robin sequence may aggravate the retroposition of the mandible and may thus be a pathogenetic factor contributing to the severe respiratory problems.

Alginates↗
PubMed1999

Long-term stability of treatment results after upper jaw segmented osteotomy according to Schuchardt for correction of anterior open bite.

Upper jaw osteotomy according to Schuchardt is a relatively rarely performed surgical procedure due to its narrow range of indications. Within the framework of a clinical follow-up examination using this method, we studied the long-term results in 26 patients, employing cephalometric analysis and analyzing the clinical findings. The results of this study show that the outcome of the operative correction of anterior open bite remained largely stable. Although partial relapse occurred in 3 cases (= 11.5%), there was a significant functional and esthetic improvement in comparison with the preoperative initial findings. When indicated, upper jaw osteotomy according to Schuchardt is thus a suitable surgical technique for correction of anterior open bite.

Adolescent↗
PubMed1999

Experimental comparative study of various mouthguards.

The aim of this study was to evaluate the mechanical and physical properties of several standard size commercially available mouthguards. For the purpose of objective testing, a special study model, which the various gum shield devices could be fitted onto, was developed to record tooth deflection caused by impact forces induced by a pendulum ram impact testing machine. The data measured on teeth provided with various gum shield devices were correlated with those of unprotected teeth; this enabled the individual cushioning effects of the respective devices and their specific force conduction to be evaluated. Using mouthguards considerably diminishes the deflection of the teeth subjected to stress in comparison with the row of unprotected teeth. In addition, force is transmitted to the adjacent teeth all the way to the distal regions of the row of teeth. The individual cushioning effects are directly correlated to the thickness of the material; the force distribution is determined by the rigidity of the gum shield device. The devices examined showed considerable differences with regard to force distribution and dimensioning. The study showed that this was due to the thickness of the materials, the manufacturing process and the composition of the materials of the devices examined. In comparison to laboratory-produced devices of similar material thickness, the devices that were designed to be fitted by the user achieved significantly poorer results as regards both cushioning properties and dissipation of exerted forces.

Athletic Injuries↗
PubMed1998

Malocclusion and the need for orthodontic treatment in 9-year-old children. Survey based on the Swedish National Board of Health and Welfare Scale.

In this study the prevalence of malocclusion and the need for orthodontic treatment was studied in 1,020 children (541 boys and 479 girls). At the time of examination they were between the ages of 8 years 5 months and 9 years 5 months. The frequency of dental, space and occlusion anomalies was recorded and compared with those in other studies. The need for orthodontic treatment was judged according to the 5-point scale of the Swedish National Board of Health and Welfare (1996). In 32% of the children there was an urgent need for treatment (Grade 3 and 4) in a further 32% treatment would be desirable (Grade 2). There was a little need for treatment (Grade 1) in 24% and no need (Grade 0) in 12%.

Child↗
PubMed1998

Three-dimensional analysis of cleft palate topology in newborn infants with reference to the cranial skeleton.

OBJECTIVE: To describe a method of determining the three-dimensional topology of the palatal crest relative to a reproducible anthropomorphic coordinate system in newborn infants with unilateral cleft palate. For this purpose, physical models of the maxilla and face were analyzed by computer morphometry. DESIGN: The study was limited to infants referred to the craniofacial center during the first 11 days after birth. SETTING: The study was performed at a craniofacial center servicing a large geographic area. PARTICIPANTS: The method was applied to 12 infants with unilateral cleft lip, alveolus, and palate (eight patients with left-side clefts and four with right-side clefts). MAIN OUTCOME MEASURES: The three-dimensional topology of the palatal crest referenced to an anthropometric coordinate system was the primary outcome measure. The anthropometric reference system is defined by the tragus points and the midpoint of a line connecting the endocanthia. RESULTS: The topology of the maxillary crests of the patients was characterized by considerable variability. The center of the premaxilla as defined by the attachment of the frenulum was frequently displaced by several millimeters from the midsagittal plane. The displacement was to the left in infants with right-side clefts and to the right in infants with left-side clefts. The premaxilla can be rotated by more than 30 degrees relative to the normal position. No significant retroposition of the minor segment as determined by the location of the tuber points was found. Several morphometric anomalies were found to be correlated linearly. CONCLUSIONS: We propose that the morphologic deviations are in part caused by the neuromotor activity of the tongue and of the interrupted M. orbicularis oris. The data can serve as the starting point for a longitudinal study of craniofacial development in children with cleft palate and for studies on the efficacy of different therapeutic approaches.

Alveolar Process↗
PubMed1997

Reliability of electromagnetic articulography recording during speaking sequences.

For the development of malocclusions and speech disorders, major aetiological significance is attributed to orofacial malfunctions, especially of the tongue. The position of the tongue to the alveolar arch and teeth, particularly within the area of the tip of the tongue, is of special interest for orthodontists. Electromagnetic articulography is a new technique used to examine tongue function and to record its movement in the midsagittal plane. The aim of the study was to determine whether this procedure offers suitable and reliable results. Thirty-one subjects aged 14.3-37.3 years had to repeat speaking sequences five times. The German syllables they had to repeat were /asa/, /ascha/, /ata/, /ala/, /ana/, /aka/. The tongue movements were registered with an 'Articulograph AG 100'. Distances, angles and encircled planes were evaluated, and the proportion of intra-individual to overall variability was calculated in order to check the reliability of the courses of movement. Angles and distances especially showed, depending on the position of the receiver coils, strong reliability during speaking sequences, whereas area produced unfavourable results. The analysis of long trajectories and angles appeared favourable in order to describe the courses of movement. This required, however, a systematic assessment of functional movement with electromagnetic articulography.

Adolescent↗
PubMed1996

New clinical applications for the Jasper Jumper.

This article describes the use of the Jasper Jumper in the treatment of class III anomalies, both theoretically and with a case report. Contrary to its use in class II anomalies, the Jasper Jumper is fixed to the 6-year-molars in the lower jaw and in the canine area in the upper jaw. This results in a continuously working mechanism--independent of co-operation on the part of the patient.

Activator Appliances↗
PubMed1996

Congenital palatal ulcers in newborn infants with cleft lip and palate: diagnosis, frequency, and significance.

Congenital decubital ulcers were found in 94% of newborn infants with unilateral cleft lip and palate in the course of a systematic study of a large cohort study (N = 52). The procedures for diagnosis, documentation, and follow-up are described. The ulceration area at birth varied over a wide range. The ulcerations were usually located in the posterior part of the vomer. Sonographic evidence supports the hypothesis that the ulcerations are caused mechanically by the motor activity of the tongue during the fetal and newborn period. The decubital ulcer disappeared in each case within 5 days following the implementation of a palatal plate.

Cleft Lip↗
PubMed1995

[Maximal force measurements of lip and tongue pressures and their significance for the diagnosis of orofacial dyskinesias].

The functioning of the orofacial muscular system essentially determines the shape of the jaw and of the dental arch as well as the position of the axis of the anterior teeth. Disturbances of the normal functioning can cause anomalies of the position of teeth or malformations of the bone structure. With the help of the newly developed device "Myometer 160" we now have the possibility to measure the intra- and extraoral forces. We examined 107 persons aged 8 to 37 years. The maximal force was measured by ventral tongue pressure, when the lips were pressed against each other and when a brass button was pulled. In addition clinical results as well as a functional status were ascertained in order to record orofacial dyskinesias. A significant connection between the age respectively the sex of the persons and the determined force was found. However, no clear relationship between the occlusal position respectively the functional anomaly and the results of maximal force was determined. Thus it does not seem sensible to use maximal force measurement within the framework of the determined. Thus it does not seem sensible to use maximal force measurement within the framework of the diagnosis of orofacial dyskinesias.

Adolescent↗
PubMed1994

[Orthodontics and implantology. Their course and results after joint planning].

The therapeutical repertoire for treating patients with missing teeth was significantly expanded by the development of modern implant methods. We have performed a retrospective analysis covering all children who between 1977 and 1993 had been considered for implants as a method for gap management. All patients were pretreated up to early adolescence using standard orthodontic procedures. Unfortunately, it turned out that an originally planned implant was not suitable in approximately 2/3 of the patients because of inadequate alveolar conditions. These patients were subsequently treated by conventional orthodontic gap closure or adhesive prosthetics.

Adolescent↗
PubMed1993

[Force-moment measurements on the passive palatal arch under the influence of the tongue].

Forces and moments, which the tongue transmits during swallowing to transpalatinally combined first upper molars, were measured in vivo. Three basic forms of the transpalatal arch were studied: one without an additional bend, one with a horse shoe bend facing the mesial, and one with a bend towards the distal. Regardless of which kind of palatal arch was used, tongue function caused intrusive, expansive and mesial directed forces. Using the arch form without an additional bend evoked both a mesial and a distal tipping moment. The arch form with the bend facing the mesial caused a mesial tipping moment during swallowing. When the horse shoe bend faced the distal, a distal directed moment predominated. For this reason in cases involving a problematical anchorage situation, a transpalatal arch with a horse shoe bend facing the distal should be employed.

Biomechanical Phenomena↗
PubMed1992

[The importance of the center of resistance for the biology of tooth movement].

The tooth movement of loaded premolars was investigated in four two-years-old beagle dogs under general anesthesia. Two supragingival registrations were performed to calculate the center of rotation in order to estimate the amount of tipping. Loads of 5 to 20 N were applied for two to four seconds. The amount of tipping was found to be load- and time-dependent. The discrepancy between these findings and the models of analytical mechanics were explained by bone bending in our experiments. Biology and localization of periodontal remodelling is supposed to be dependent on load magnitude, load duration and physical properties of all periodontal tissues including bone.

Animals↗
PubMed1991

[Orthodontic surgical treatment of class III--the electromyographic effects on the masticatory and facial musculatures].

22 adult class-III patients, partly with considerable vertical excess, who required combined orthodontic-surgical treatment were investigated at the end of preoperative orthodontic treatment and six months postoperative. EMG activity was recorded for the m. temporalis, m. masseter, perioral and the floor of the mouth muscles during rest position and in six different active functions. Postoperative activities revealed a significant reduction for most muscles in almost all functions. Additionally right-left differences were reduced. This effect is regarded to be a sign of more efficient muscular action due to improved biomechanical and occlusal conditions so that defined functions can be exerted by less muscular activation.

Adolescent↗