Olli Rönning

Craniofacial morphology in preschool children with sleep-related breathing disorder and hypertrophy of tonsils.

The purpose of this study was to examine craniofacial morphology, pharyngeal airway space and hyoid bone position in preschool children with sleep‐related breathing disorder associated with hypertrophy of tonsils (SBDT). Thirty‐eight preschool children, mean age 4.7 y, with SBDT and with an apnoea index (AI) of 0 < AI <5, were divided into two groups. One consisted of 15 children with sleep‐related breathing disorder (SBD) and more than 75% of the tonsils visible (GUI) and the other of 23 children with SBD and 25–75% of the tonsils visible (Gil). The control group consisted of 31 children without ear, nose and throat disease and with GI (barely visible) tonsils. Compared with the controls, GUI children had a retrognathic mandible, a large posterior facial height, a large interincisal angle with retroclined lower incisors, a narrow pharyngeal airway space, an anterior tongue base position and a long soft palate. Compared with the controls, Gil children had a large anterior lower facial height and a short nasal floor. However, like the controls, Gil children did not have a retrognathic mandible.

Abnormal craniofacial growth and early mandibular osteoarthritis in mice harbouring a mutant type II collagen transgene

Skull morphology and histology in the heterozygous offspring of a transgenic founder mouse Del1, harbouring 6 copies of deletion mutation in Col2a1 gene, were compared with those in normal siblings. On visual observation and roentgenocephalometric examination the heads of heterozygous Del1 mice were smaller than normal. Histologically the sizes of cartilaginous structures of the cranial base were reduced. Severe defects were seen in the temporomandibular joint as progressive osteoarthritic lesions. These observations elucidate the relationship between the genotype and phenotype and demonstrate that heterozygous Del1 mice are a useful model for studies on a genetic disturbance where ‘clinical’ manifestations are not evident until adult age.

Disturbances in craniofacial morphology in children treated for solid tumors

Because of increased survival rates in childhood cancer, special interest has been focused on the side-effects of the therapy and the quality of life in long-term survivors. Our aim was to investigate craniofacial growth in children who had received different kinds of antineoplastic therapies for solid tumors. A total of 40 children treated in the Turku University Central Hospital were examined and divided into three different groups. Group 1 comprised 18 children treated for intracranial tumors with cranial irradiation (CRI) and chemotherapy (CT) including alkylating agents. Seven children out of 18 in this group received growth hormone (GH) therapy. In Group 2, 11 children with extracranial solid tumors also received multiagent CT including alkylating agents, but no CRI. Group 3 consisted of 11 children treated for Wilms tumor with CT, which did not include alkylating agents or CRI. A total of 19 linear and four angular variables from the lateral cephalograms of the subjects were measured. Most deviations in craniofacial structures were found in children treated with combined CRI and multiagent CT. All disturbances were seen in the vertical measurements which were reduced when compared to the matched controls. It seems reasonable to assume that impaired growth following combined radio- and chemotherapy, as well as GH treatment, particularly affects cartilage-mediated growth. However, the deviations seen in the present study were fairly minor and did not usually require clinical consideration.

Weaning and the Histology of the Mandibular Condyle in the Rat

Eighty-eight Long Evans/Turku rats were used in the study. The effect of the articulatory function on the mandibular condyle was observed histologically during normal growth, when the rat is changing its diet from milk to whole pellets as a part of weaning. Six animals each were killed at the age of 10, 15, 20, 25, 30, 35, 40 and 50 days for histological tissue processing. For further information, 30 animals were fed a soft diet (6 animals each were killed at the age of 25, 30, 35, 40 and 50 days), and 10 animals were fed hardened pellets (2 animals each were killed at the ages of 25, 30, 35, 40 and 50 days). An even and regular transition from mesenchymal cells via immature chondroblasts into mature chondroblasts and hypertrophied chondrocytes was found at 10, 15 and 20 days during normal growth and also at 25, 30, 35, 40 and 50 days when animals were fed a soft diet. This maturing process appeared to be disturbed at the age of 25, 30, 35 and 40 days in the superior aspect of the condyle in animals fed ordinary pellets. The density of the mesenchymal cell layer was decreased, and the amount of intercellular matrix seemed to be evaluated in mesenchymal and intermediate cell layers. These features were later manifest deeper in the cartilage as acellular regions and as cell clusters. The changes were similar but more severe when the animals were fed hardened pellets.(ABSTRACT TRUNCATED AT 250 WORDS)

Cephalometric evaluation of facial types in preschool children without sleep-related breathing disorder

OBJECTIVE this study was aimed at characterizing the craniofacial structures, i.e. the facial skeleton, cranial base, dentition, pharyngeal airway space, and the hyoid bone position, in healthy preschool children without sleep-related breathing disorder. MATERIALS AND METHODS from lateral cephalometric radiographs taken of 92 children for diagnostic purposes, 45 were selected for the present investigation on the basis of head position, and divided according to the classification of Siriwat and Jarabak (Angle Orthod. 55 (1985) 127) into groups representing counter-clockwise (CC), straight downward (SD), and clockwise (C) facial types. RESULTS the findings showed that, in comparison with the other groups, CC is associated with larger facial taper and posterior facial height, smaller mandibular line angle, ramus position, lower facial height and cranial base angle. By a similar comparison, C is associated with larger mandibular line, gonial angles and convexity, and with a smaller L-1 to mandibular line angle. There were no significant differences in hyoid bone position among the three groups. However, the distance of the lower pharynx was smaller in CC than in C, while the tongue base of CC was noted to be in a posterior position. CONCLUSIONS thus, the results indicate that there are significant differences in the madibular position and form among the present three groups of children. It is proposed that the objective of vertical facial control ought to be included in the treatment of preschool children with malocclusion and respiratory disorder.

Absence of facial type differences among preschool children with sleep-related breathing disorder

The aim of this study was to find out whether there are specific facial types and a specific hyoid bone position in preschool children with sleep-related breathing disorder (SBD). A total of 69 children were divided into 4 groups based on the mandibular line/Frankfurt horizontal angle and apnea index. There were 19 children with hyperdivergent facial type and SBD and 19 children with neutral facial type and SBD, all of them with documented 0 < AI. Ten children had hyperdivergent facial type and non-SBD, and 21 children neutral facial type and non-SBD. The present findings show that SBD may be associated with both hyperdivergent and neutral facial type. Furthermore, we could not find any specific hyoid bone position related to SBD, non-SBD, or to facial type. In conclusion, it is important to note that while evaluation based on facial type (mandibular shape or position) does not necessarily distinguish between children with SBD and children without SBD (non-SBD), important differences are found in the pharynx. Short nasal floor length, long soft palate, and particularly short upper pharyngeal width can be considered indicators of SBD.

Relation of the glenoid fossa to craniofacial morphology, studied on dry human skulls

The purpose of this work was to compare glenoid fossa dimensions and craniofacial morphology on the basis of standard lateral roentgenograms. To overcome the difficulties encountered in making exact measurements on living subjects, 59 dry skulls were used. Eight angular measurements were taken to describe the form of the skull base, mandible, and articulating surface of the glenoid fossa, four linear measurements to describe the position of the fossa, and one to describe the size of the whole skull. A close relationship was observed between the morphology of the articulating surface of the glenoid fossa and the mandibular morphology. The skull base angulation was associated with the position of glenoid fossa in two ways. Basically, the position of the fossa is related to skull base characteristics, but the location of the articular eminence in relation to the clival plane suggests that the mandibular condyle may cause a remodeling of the eminence anteriorly when the glenoid fossa otherwise is translocated posteriorly in association with the flat skull base.

Basicranial synchondroses and the mandibular condyle in craniofacial growth

Basicranial synchondroses are remnants of the fetal chondrocranium and thus represent primary cartilage, whereas the chondral part of the mandibular condyle, for example, develops unattached to the chondrocranium, as secondary cartilage. The two cartilage groups show differences in structure and cell proliferation pattern, and yet both are endowed with tissue-separating qualities.

Craniofacial growth in shunt-treated hydrocephalics: a four-year roentgenocephalometric follow-up study

The craniofacial growth of 24 shunt-treated hydrocephalics aged 5–15 years was evaluated over a 4-year period, by comparing changes in linear and angular cephalometric variables with those of an age- and sexmatched control group. The main findings were increased calvarial thickness, increased cranial base flexure, superior displacement of the sella, and a tendency for the gonial angle to remain more obtuse in the shunt-treated patients. As craniofacial growth in the latter differed only slightly from that observed in the controls, the deviations in facial morphology observed in a previous cross-sectional study of shunt-treated hydrocephalics can be taken to represent a long-term effect of the shunt treatment.

Effect of Freezing Damage of the Periosteum on the Growth of the Mandibular Condylar Process in the Rat

The regulatory effect of the periosteum on the growth of the mandibular condylar process has previously been investigated by relieving the periosteal tension, e.g. by dividing the periosteum, but no unanimous conclusion has been reached. In the present investigation, a different experimental design was applied in that the growth of the condylar process was observed following a provoked periosteal damage. Using 15-day-old rats, the mandibular ramus on the right side was exposed, and the periosteum subjacent to the condylar cartilage was frozen by a cryotechnique. Controls were treated similarly, with the exception of the freezing. The height of the ramus and the length of the mandibular corpus were measured on separated dry mandibular halves 15 or 30 days postoperatively. The measurements showed that the mandibular halves on which the periosteum had been frozen were significantly smaller than the contralateral ones. A tendency in the same direction was also found in the sham-operated animals. It can be concluded that the presumably increased restriction following damage to the periosteum, and evidently also scarring resulting from the operation, has an inhibitory effect on the growth of the condylar process. However, it is still open to discussion whether the reduced growth is transmitted by mechanical means according to the periosteal-tension hypothesis and/or by here unspecified mitogenic factors.