Skeletal stability in patients with clefts after large maxillary advancements using intraoral distraction.

Maxillary hypoplasia is a common outcome in patients with cleft lip and palate after surgical and orthodontic interventions, and maxillary distraction osteogenesis has become a useful procedure for patients with extensive maxillary deformities. The aim of this study was to evaluate long term (two years) stability after maxillary advancement of more than 10mm by distraction osteogenesis in cleft patients using internal devices. We organised a retrospective study on 42 patients with cleft lip and palate using cephalometric analysis before and after maxillary distraction osteogenesis and evaluated them for 24 months. Postoperative measurements showed a marked advancement with an increase of 13.3mm and 10.8° in the length of the maxilla (Co-A) and SNA, respectively, including a shift from Angle class III to class I in dental relations. Follow-up observations showed preservation of maxillary length with a relapse of only 6.0 % (mean (SD) 0.8 (0.7) mm) and 10% relapse in SNA angle (mean (SD)1.1 (1.4) °) one year postoperatively and a negligible regression at the two years' follow up. This large-scale study shows stable results of skeletal advancement using distraction osteogenesis, indicating safe and reliable outcomes among patients with cleft lip and palate.

Pregnancy decreases immunoreactive parathyroid hormone level in rats with chronic renal failure.

Normal pregnancy is associated with an increase in serum parathyroid hormone and 1,25-dihydroxyvitamin D3 (calcitriol). The effect of pregnancy on these hormones in chronic renal failure (CRF) is unknown. The present work was undertaken to study the changes of serum immunoreactive parathyroid hormone (iPTH) and calcitriol in pregnant rats with CRF. The following experimental groups were studied: CRF1 (5/6 nephrectomized virgin female rats), CRF2 (5/6 nephrectomized pregnant rats at day 20-21 of pregnancy), CRF3 (5/6 nephrectomized rats 2 weeks after delivery) and their respective sham-operated control groups: N1, N2 and N3. The 5/6 nephrectomy (CRF1) resulted in renal failure with very high serum iPTH (100+/-18 pg/ml) and low calcitriol levels (10.6+/-4.3 pg/ml) compared with normal rats [N1: 14+/-2.5 pg/ml (P<0.001) and 18.2+/-4.2 pg/ml (P<0.01) respectively]. The pregnancy in CRF rats (CRF2) resulted in normalization of serum iPTH levels (18.2+/-5.41 pg/ml), which was associated with a parallel increase in serum calcitriol (29.4+/-8.0 pg/ml) similar to that in pregnancy of normal rats (N2). Two weeks after delivery the CRF rats (CRF3) once again had high serum iPTH (87+/-17 pg/ml) and low calcitriol levels (9.3+/-1.2 pg/ml), similar to those observed in non-pregnant uraemic rats (CRF1). It is concluded that pregnancy decreases serum iPTH in 5/6 nephrectomized CRF rats most probably by the increased level of calcitriol synthesized by the feto-placental unit.