Nonsynostotic Cranial Deformity: A Six-Month Matched-Pair Photogrammetric Comparison of Treated and Untreated Infants

Objective

To photogrammetrically objectify changes in nonsynostotic craniofacial deformity in orthotically treated versus untreated infants.

Design

A statistical retrospective pairwise comparison of two respective three-dimensional (3D) photo scans of 80 children performed in a 6-month time lag.

Patients

Two comparable samples of children (40 treated, 40 untreated) with nonsynostotic cranial deformity.

Interventions

Respective 3D photo scans were matched using Cranioform Analytics 4.0 software.

Main Outcome Measures

Median change of 30° Cranial Vault Asymmetry Index (CVAI), modified CVAI (CVAImod), Cranial Index (CI), and posterior symmetry ratio (PSR).

Results

We found an improvement in Δ30° CVAI by 3.3% (treated) and by 1.31% (untreated), respectively. CVAImod improved by 3.46% in the treated group and by 1.55% in the untreated group. CI improved by 4.41% in the treated group and by 3.68% in the untreated group, and PSR improved by 0.71 in the treated group and 0.49 in the untreated group. Although improvement of cranial asymmetry was higher in those children treated with an individual molding orthosis, we could not document a statistically significant difference between the two groups.

Conclusions

Helmet therapy may be less appropriate for the correction of brachycephaly than for cranial asymmetry. Nonsynostotic cranial deformity shows some spontaneous correction. Photogrammetry presents an accurate method to objectify craniofacial changes in early infancy.

Non-linear 3D evaluation of different oral implant-abutment connections

Micro-gaps and osseous overload in the implant-abutment connection are the most common causes of peri-implant bone resorption and implant failure. These undesirable events can be visualized on standardized three-dimensional finite element models and by radiographic methods. The present study investigated the influence of 7 available implant systems (Ankylos, Astra, Bego, Brånemark, Camlog, Straumann, and Xive) with different implant-abutment connections on bone overload and the appearance of micro-gaps in vitro. The individual geometries of the implants were transferred to three-dimensional finite element models. In a non-linear analysis considering the pre-loading of the occlusion screw, friction between the implant and abutment, the influence of the cone angle on bone strain, and the appearance of micro-gaps were determined. Increased bone strains were correlated with small (< 15°) cone angles. Conical implant-abutment connections efficiently avoided micro-gaps but had a negative effect on peri-implant bone strain. Bone strain was reduced in implants with greater wall thickness (Ankylos) or a smaller cone angle (Bego). The results of our in silico study provide a solid basis for the reduction of peri-implant bone strain and micro-gaps in the implant-abutment connection to improve long-term stability.

Accuracy of three-dimensional photogrammetric images in non-synostotic cranial deformities

OBJECTIVE

Given the increasing incidence of deformational plagiocephaly due to infants' supine sleeping position to prevent sudden infant death syndrome, reliable anthropometric diagnostics are needed. Besides the traditional method of measuring landmarks with callipers, three-dimensional (3D) photography has great potential. In this investigation the accuracy of 3D photogrammetry is studied.

METHODS

The study included 100 randomly chosen children between the ages of 4 and 20 months with a non-synostotic cranial deformity in a retrospective analysis. Measurements of diagonals A and B on the infant's head were obtained once using callipers. 3D photographs of these children were measured 5 times by 5 clinicians separately.

RESULTS

The inter- and intra-rater agreements of the 3D measurements had low variability in the variance component analysis. The standard deviations for reproducibility and repeatability were 0.117-0.283 cm for diagonals A and B. The intra-class correlation coefficients for the inter-rater reliability resulted in excellent agreement (0.97 for plagiocephaly, 0.98 for brachycephaly, 0.96 for combined deformity). The comparison of the 3D photographic and callipers measurements showed that 3D photography resulted in a slight over-estimation.

CONCLUSION

3D photogrammetry is potentially a reliable tool for treatment planning and follow-up of abnormal head shapes in infancy.

Topical use of platelet-rich plasma to influence bone volume in maxillary augmentation: a prospective randomized trial

BACKGROUND AND OBJECTIVES

The atrophic posterior maxilla often requires restoration of the alveolar ridge due to a lack of bone quantity and quality before dental implant placement. The aim of this study was to verify the hypothesis that platelet-rich plasma (PRP) has an influence on bone density in the maxilla after sinus floor elevation in combination with autologous cancellous bone from the iliac crest. Therefore, a randomized, prospective, controlled trial was set up in two centres.

STUDY DESIGN AND METHODS

Fifty-three patients who underwent osteoplastic bone grafting for sinus floor elevation were included. The intervention group was treated with defined concentrations of PRP in addition to transplanted bone. Bone biopsy was performed 4 months after augmentation. Bone volume was then measured using the histomorphometric parameter bone volume.

RESULTS

The histomorphometric evaluation of the biopsies did not indicate superiority of any of the treatments in terms of bone volume.

CONCLUSION

Topical use of PRP did not improve maxillary bone volume either clinically relevant or statistically significant compared to that in conventionally treated patients. The use of PRP to support bone regeneration cannot be recommended as a standard method for maxillary augmentation.