Treatment of infra-occluded primary molars in patients with dental ageneses.

When dental agenesis is encountered, several treatment solutions can be considered: extraction of the primary tooth and closure of the space or, alternatively, conservation of the space with the primary tooth still on the arch until a prosthesis can be placed. In the presence of premolar agenesis, the corresponding primary molar may be infra-occluded relative to the occlusal plane. This situation complicates the treatment plan. Depending on the clinical setting, it can be useful to restore occlusal contacts using composite overlays. We will demonstrate this treatment option via two clinical cases. Tooth conservation helps maintain the bone volume that will later facilitate placement of an implant and limit extrusion of the antagonists as well as tipping of the neighboring teeth.

Wnt/ß-catenin signaling and Msx1 promote outgrowth of the maxillary prominences.

Facial morphogenesis requires a series of precisely orchestrated molecular events to promote the growth and fusion of the facial prominences. Cleft palate (CP) results from perturbations in this process. The transcriptional repressor Msx1 is a key participant in these molecular events, as demonstrated by the palatal clefting phenotype observed in Msx1(-/-) embryos. Here, we exploited the high degree of conservation that exists in the gene regulatory networks that shape the faces of birds and mice, to gain a deeper understanding of Msx1 function in CP. Histomorphometric analyses indicated that facial development was disrupted as early as E12.5 in Msx1(-/-) embryos, long before the palatal shelves have formed. By mapping the expression domain of Msx1 in E11.5 and E12.5 embryos, we found the structures most affected by loss of Msx1 function were the maxillary prominences. Maxillary growth retardation was accompanied by perturbations in angiogenesis that preceded the CP phenotype. Experimental chick manipulations and in vitro assays showed that the regulation of Msx1 expression by the Wnt/ß-catenin pathway is highly specific. Our data in mice and chicks indicate a conserved role for Msx1 in regulating the outgrowth of the maxillary prominences, and underscore how imbalances in Msx1 function can lead of growth disruptions that manifest as CP.

The acceleration of implant osseointegration by liposomal Wnt3a.

The strength of a Wnt-based strategy for tissue regeneration lies in the central role that Wnts play in healing. Tissue injury triggers local Wnt activation at the site of damage, and this Wnt signal is required for the repair and/or regeneration of almost all tissues including bone, neural tissues, myocardium, and epidermis. We developed a biologically based approach to create a transient elevation in Wnt signaling in peri-implant tissues, and in doing so, accelerated bone formation around the implant. Our subsequent molecular and cellular analyses provide mechanistic insights into the basis for this pro-osteogenic effect. Given the essential role of Wnt signaling in bone formation, this protein-based approach may have widespread application in implant osseointegration.