The aim of this study was to measure craniofacial morphology and nasal respiratory resistance (NRR) in Malay, Indian and Chinese subjects with obstructive sleep apnoea (OSA). The sample consisted of 34 male subjects, 27-52 years of age (Malay n = 11, which included five mild and six moderate-severe OSA; Indian n = 11, which included six mild and five moderate-severe OSA; and Chinese n = 12, which included six mild and six moderate-severe OSA) diagnosed using overnight polysomnography. After use of a decongestant, NRR was recorded using anterior and posterior rhinomanometry. Standardized lateral cephalometric radiographs were used to record linear and angular dimensions. Malay subjects with moderate-severe OSA had a shorter maxillary (sp-pm) and mandibular (gn-go) length when compared with a mild OSA reference sample (P < 0.05). The hyoid bone was located more caudally in the Chinese moderate-severe subjects (hy-NL, hy-ML)(P < 0.05), and may be a useful diagnostic indicator for severity in this racial group. No pattern of differences for NRR was seen between the moderate-severe and mild OSA subjects. The consistently lower values for nasopharyngeal resistance in all the moderate-severe subjects when compared with the mild group may indicate that some compensation at this level of the airway had taken place. Strong positive correlations between craniocervical angulation (NL/OPT) and total airway resistance and the turbulent component of flow (k(2)) suggest that head posture is sensitive to fluctuations in airway resistance (P < 0.01).
This in vivo study revealed that porous hydroxyapatite (PHA) and dense hydroxyapatite (DHA) are good implant materials that can accelerate bone healing and resorbed in acceptable time. But there were differences in the mechanism of the resorption of DHA and PHA due to variability in the physical properties and osteogenicity.
A cephalometric study using Downs' analysis was undertaken with lateral cephalometric radiographs for a mixed sample of 50 child, adolescent and young adult Indonesians who presented with Angle Class I occlusions. Significant differences between this study group and the published results from comparative racial types were found for Downs' angle of convexity, Y-axis and incisor inclinations, indicating that Indonesians can be differentiated from other races with similar occlusions by using Downs' analysis.
This study aimed to investigate residual ridge resorption (RRR) of anterior and posterior maxillary and mandibular edentulous ridges, in patients treated with mandibular implant overdentures (IOD) and compare with conventional complete denture (CD) wearers, and to determine at each location, the association of RRR with the occlusal forces distribution and other patients' variables. The anterior and posterior RRR of IOD (six males, 17 females) and CD (12 males, 11 females) groups were determined using baseline and follow-up dental panaromic radiographs (DPT) (mean intervals 4 ± 1·8 years). The bone ratios were calculated using proportional area: anatomic to fixed reference areas and mean difference of ratios between the intervals determined RRR. The ridge locations included anterior and posterior maxillary and posterior mandibular arches. The T-Scan III digital occlusal system was used to record anterior and posterior percentage occlusal force (%OF) distributions. There were significant differences in anterior and posterior %OF between treatment groups. Two-way anova showed RRR was significant for arch locations (P = 0·005), treatment group (IOD versus CD) (P = 0·001), however, no significant interaction (P = 0·799). Multivariate regression analyses showed significant association between RRR and %OF at anterior maxilla (P = 0·000) and posterior mandible (P = 0·023) and for treatment groups at posterior maxilla (P = 0·033) and mandibular areas (P = 0·021). Resorption was observed in IOD compared to CD groups, with 8·5% chance of less resorption in former and 7·8% in the latter location. Depending on arch location, ridge resorption at various locations was associated with occlusal force distribution and/or treatment groups (implant prostheses or conventional complete dentures).
Defects were created in the mandible of a rabbit model whereby the right side was implanted with hydroxyapatite (HA) while the left side was left empty to act as control. Both the implant and control sites were evaluated clinically and histologically at 4,12,20,22 weeks. Decalcified sections were studied under confocal laser scanning microscope. No reactive cells were evident microscopically in all sections. There was bone ingrowth as early as 4 weeks when viewed by the topographic method. Enhancement of osteoconduction was evident by the presence of abundant capillaries, perivascular tissue and osteoprogenitor cells of the host. At 22 weeks, the implanted defect showed mature bone formation filling almost the whole field. This study demonstrated that the dense HA exhibits excellent biocompatibility as noted by the complete absence of reactive cells. It also promotes osteoconduction.