Timo Peltomäki

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 mandibular growth and the condylar cartilage

Deviations in the growth of the mandibular condyle can affect both the functional occlusion and the aesthetic appearance of the face. The reasons for these growth deviations are numerous and often entail complex sequences of malfunction at the cellular level. The aim of this review is to summarize recent progress in the understanding of pathological alterations occurring during childhood and adolescence that affect the temporomandibular joint (TMJ) and, hence, result in disorders of mandibular growth. Pathological conditions taken into account are subdivided into (1) congenital malformations with associated growth disorders, (2) primary growth disorders, and (3) acquired diseases or trauma with associated growth disorders. Among the congenital malformations, hemifacial microsomia (HFM) appears to be the principal syndrome entailing severe growth disturbances, whereas growth abnormalities occurring in conjunction with other craniofacial dysplasias seem far less prominent than could be anticipated based on their often disfiguring nature. Hemimandibular hyperplasia and elongation undoubtedly constitute the most obscure conditions that are associated with prominent, often unilateral, abnormalities of condylar, and mandibular growth. Finally, disturbances of mandibular growth as a result of juvenile idiopathic arthritis (JIA) and condylar fractures seem to be direct consequences of inflammatory and/or mechanical damage to the condylar cartilage.

Associations between severity of clefting and maxillary growth in patients with unilateral cleft lip and palate treated with Infant orthopedics

OBJECTIVE The purpose of this study was to examine possible associations between severity of clefting in infants and maxillary growth in children with complete unilateral cleft lip and palate. DESIGN This was a retrospective study of measurements made on infant maxillary study casts and maxillary cephalometric variables obtained at 5 to 6 years of follow-up. SETTING The study was performed at the Institute of Reconstructive Plastic Surgery of New York University Medical Center, New York, New York. PATIENTS Twenty-four consecutive nonsyndromic unilateral complete cleft lip and palate patients treated during the years 1987 to 1994. INTERVENTIONS All the patients received uniform treatment (i.e., presurgical orthopedics followed by gingivoperiosteoplasty to close the alveolar cleft combined with repair of the lip and nose in a single stage at the age of 3 to 4 months). Closure of the palate was performed at the age of 12 to 14 months. RESULTS Infant maxillary study cast measurements correlated in a statistically significant manner with maxillary cephalometric measurements at age 5 to 6 years. CONCLUSIONS The results demonstrate the large variation in the severity of unilateral cleft lip and palate deformity at birth. Patients with large clefts and small arch circumference, arch length, or both demonstrated less favorable maxillary growth than those with small clefts and large arch circumference or arch length at birth.

Growth of a costochondral graft in the rat temporomandibular joint

The aim of this study was to examine the growth and adaptation of costochondral grafts in the temporomandibular joint (TMJ). An autogenous rib section with either a short, intermediate, or long cartilaginous end was transplanted to replace the right mandibular condyle in 20-day-old rats. At 40 days, the mandibular halves with the short cartilage transplants were shorter than the contralateral halves, whereas the two sides did not differ in length in the rats with the intermediate transplant. The mandibular halves with the longest cartilaginous transplants initially were longer than the contralateral ones. The glenoid fossa was located more laterally as compared with the unoperated side. The results provide evidence that costochondral transplants do not adapt to the functional conditions of the TMJ and that the amount of cartilage in the graft has some bearing on its growth capacity.

Long-term changes in pharyngeal airway dimensions following activator-headgear and fixed appliance treatment

The aim of this study was to evaluate changes in the pharyngeal airway in growing children and adolescents and to compare these with a group of children who received activator-headgear Class II treatment. The sample consisted of 64 children (32 males and 32 females), 32 had a combined activator-headgear appliance for at least 9 months (study group) followed by fixed appliance therapy in most patients, while the other half received only minor orthodontic treatment (control group). Lateral cephalograms before treatment (T1, mean age 10.4 years), at the end of active treatment (T2, mean age 14.5 years), and at the long-term follow-up (T3, mean age 22.1 years) were traced and digitized. To reveal the influence of somatic growth, body height measurements were also taken into consideration. A two-sample t-test was applied in order to determine differences between the groups. At T1, the study group had a smaller pharynx length (P = 0.030) and a greater ANB angle (P < 0.001) than the controls. The pharyngeal area and the smallest distance between the tongue and the posterior pharyngeal wall also tended to be smaller in the study group. During treatment (T1-T2), significant growth differences between the two groups were present: the study group had a greater reduction in ANB (P < 0.001) and showed a greater increase in pharyngeal area (P = 0.007), pharyngeal length (P < 0.001) and the smallest distance between the tongue and the posterior pharyngeal wall (P = 0.038). At T2, the values for the study group were similar to those of the control group and remained stable throughout the post-treatment interval (T2-T3). Activator-headgear therapy has the potential to increase pharyngeal airway dimensions, such as the smallest distance between the tongue and the posterior pharyngeal wall or the pharyngeal area. Importantly, this increase seems to be maintained long term, up to 22 years on average in the present study. This benefit may result in a reduced risk of developing long-term impaired respiratory function.

Mandibular asymmetry in healthy children.

Facial asymmetry is a naturally occurring phenomenon that is often due to differences in the mandibular dimensions on the right and left sides. The point where normal asymmetry turns abnormal cannot be easily defined, and no standards exist by which a judgement of abnormality can be made. The aim of the present study was to assess mandibular asymmetry in healthy children and its possible fluctuation during growth. The subjects consisted of 182 healthy children (88 girls, 94 boys) who had had an orthopantomogram taken at ages 7 (mean 7.5 years) and 16 (mean 15.9 years). On digitized orthopantomograms, condylar and ramus heights on both mandibular sides were measured with a Numonics Accugrid digitizer (Numonics Co., Montgomeryville, Pa., USA) and analysed with X-metrix software (Smart Systems, Turku, Finland). A paired t-test was used to determine the significance of the differences between the sides, and ANOVA to test the significance of the change in asymmetry during growth and between genders. The results revealed a statistically significant difference between the right and left sides in condylar height at age 7 years, in ramus height at both ages, and in the condylar and ramus height at age 16 years. The present study confirms that healthy young subjects generally have a statistically significant mandibular asymmetry, which, however, is only seldom clinically significant. The decision to initiate treatment because of asymmetry has to be carefully considered, since the study further showed that mandibular asymmetry may diminish or appear during growth of healthy subjects.

Accuracy of linear intraoral measurements using cone beam CT and multidetector CT: a tale of two CTs

OBJECTIVES The aim was to compare the accuracy of linear bone measurements of cone beam CT (CBCT) with multidetector CT (MDCT) and validate intraoral soft-tissue measurements in CBCT. METHODS Comparable views of CBCT and MDCT were obtained from eight intact cadaveric heads. The anatomical positions of the gingival margin and the buccal alveolar bone ridge were determined. Image measurements (CBCT/MDCT) were performed upon multiplanar reformatted data sets and compared with the anatomical measurements; the number of non-assessable sites (NASs) was evaluated. RESULTS Radiological measurements were accurate with a mean difference from anatomical measurements of 0.14 mm (CBCT) and 0.23 mm (MDCT). These differences were statistically not significant, but the limits of agreement for bone measurements were broader in MDCT (-1.35 mm; 1.82 mm) than in CBCT (-0.93 mm; 1.21 mm). The limits of agreement for soft-tissue measurements in CBCT were smaller (-0.77 mm; 1.07 mm), indicating a slightly higher accuracy. More NASs occurred in MDCT (14.5%) than in CBCT (8.3%). CONCLUSIONS CBCT is slightly more reliable for linear measurements than MDCT and less affected by metal artefacts. CBCT accuracy of linear intraoral soft-tissue measurements is similar to the accuracy of bone measurements.

Is the use of the cervical vertebrae maturation method justified to determine skeletal age? A comparison of radiation dose of two strategies for skeletal age estimation

The aim of this study was to assess effective doses of a lateral cephalogram radiograph with and without thyroid shield and compare the differences with the radiation dose of a hand-wrist radiograph. Thermoluminescent dosimeters were placed at 19 different sites in the head and neck of a tissue-equivalent human skull (RANDO phantom). Analogue lateral cephalograms with and without thyroid shield (67 kV, 250 mA, 10 mAs) and hand-wrist radiographs (40 kV, 250 mA, 10 mAs) were obtained. The effective doses were calculated using the 2007 International Commission on Radiological Protection recommendations. The effective dose for conventional lateral cephalogram without a thyroid shield was 5.03 microsieverts (µSv). By applying a thyroid shield to the RANDO phantom, a remarkable dose reduction of 1.73 µSv could be achieved. The effective dose of a conventional hand-wrist radiograph was calculated to be 0.16 µSv. Adding the effective dose of the hand-wrist radiograph to the effective dose of the lateral cephalogram with thyroid shield resulted in a cumulative effective dose of 3.46 µSv. Without thyroid shield, the effective dose of a lateral cephalogram was approximately 1.5-fold increased than the cumulative effective dose of a hand-wrist radiograph and a lateral cephalogram with thyroid shield. Thyroid is an organ that is very sensitive to radiation exposure. Its shielding will significantly reduce the effective dose. An additional hand-wrist radiograph, involving no vulnerable tissues, however, causes very little radiation risk. In accordance with the ALARA (As Low As Reasonably Achievable) principle, if an evaluation of skeletal age is indicated, an additional hand-wrist radiograph seems much more justifiable than removing the thyroid shield.

Unexpected events during mandibular distraction osteogenesis

Various unexpected events during mandibular distraction osteogenesis are described in 16 syndromic children with severely retrognathic or asymmetric lower jaws who were treated with unilateral or bilateral extraoral distraction. The mean total time with the distraction devices attached was 14 weeks (range 10–19). Although improvement in facial aesthetics and the desired occlusion was achieved in all but one case, there were unexpected events associated with mandibular distraction. These included pain not related to the operation, functional disturbance in movement of the jaw, dietary problems, weight loss, unfulfilled expectations of decannulation, temporary unilateral facial nerve palsy, and transient unilateral hypoaesthesia of the inferior alveolar nerve. Reoperation was required in 5 of the 16. In addition to these events, psychosocial problems within one family complicated the procedure. Patients and their families should be informed of the lesser‐known aspects of distraction osteogenesis before the procedure is used.

Long-term stability of anterior open bite closure corrected by surgical-orthodontic treatment

In adults, superior repositioning of posterior maxilla with or without mandibular surgery has become the treatment method of choice to close anterior open bite. Study aim was to examine the long-term stability of anterior open bite closure by superior repositioning of maxilla or by combining maxillary impaction with mandibular surgery. The sample comprised 24 patients who underwent anterior open bite closure by superior repositioning of maxilla (maxillary group, n = 12, mean age 29.3 years) or by maxillary impaction and mandibular osteotomy (bimaxillary group, n = 12, mean age 30.8 years). Lateral cephalograms were studied prior to surgery (T1), the first post-operative day (T2) and in the long term (T3, maxillary group mean 3.5 years; bimaxillary group mean 2.0 years). Paired and two-sample t-tests were used to assess differences within and between the groups. The vertical incisal bite relations were -2.6 and -2.2 mm at T1; 1.23 and 0.98 mm at T2; and 1.85 and 0.73 mm at T3 in the maxillary and bimaxillary groups. At T3, all subjects had positive overbite in the maxillary group, but open bite recurred in three subjects with bimaxillary surgery. For both groups, the maxilla relapsed vertically. Significant changes in sagittal and vertical positions of the mandible occurred in both groups. In the bimaxillary group, the changes were larger and statistically significant. In general, the maxilla seems to relapse moderately vertically and the mandible both vertically and sagittally, particularly when both jaws were operated on. Overbite seems to be more stable when only the maxilla has been operated on.