The Influence of Axial Grooves on Dislodgment Resistance of Prosthetic Metal Crowns in Canine Teeth of Dogs

Abstract

The reported failure rate for full veneer crowns of canine teeth of dogs is suboptimal, particularly in teeth with naturally poor retentive features, such as those with low height/diameter (H/D) ratios or high convergence angles (CAs). The objective of the present study was to evaluate the application of axial grooves in an effort to develop a crown preparation design that enhances the retention of full veneer crowns in dogs. Crown dislodgment testing was performed on cast alloy dies of canine teeth with unfavorable retention features (low H/D and high CA) prepared with (n = 14) and without axial grooves (n = 15) to evaluate the force required to dislodge a cemented full veneer crown. The crown/die units were secured within a universal testing machine and a load was applied at the 45° oblique direction from distal to mesial to replicate the vector encountered during biting-pulling action. The maximum force required to cause crown dislodgment was recorded for each crown. Statistical analysis revealed a significant increase in force required for crown dislodgment when axial grooves were included in the crown preparation design ( P < .001). Crown retention is improved in canine teeth with otherwise poor retention features when axial grooves are made in the labial and palatal/lingual walls during crown preparation.

Retrospective Study of 18 Titanium Alloy Crowns Produced by Computer-Aided Design and Manufacturing in Dogs

“…The geometrical configuration of the prepared clinical crown can influence success or failure of a prosthodontic crown. Several publications tried to contribute to the knowledge about the ideal configuration to improve the success of prosthodontic therapy in dogs (21–25). Tooth hight, diameter, convergence angle and other features such as axial grooves can be controlled by the operator in order to provide the best clinical crown configuration and surface area to increase its resistance and retention, ultimately affecting the longevity of the cementation.…”

“…However, faced with a second cementation/adhesion failure in the same tooth 1 month after the first episode, the authors believe that, in this case, the failure could be a consequence of insufficient surface area. For this reason, two axial grooves were added to increase surface area, since providing retention features such as axial grooves crown has been shown to increase crown retention (25). This prosthodontic crown is still in place today.…”

The Influence of Axial Grooves on Dislodgment Resistance of Prosthetic Metal Crowns in Maxillary Fourth Premolar Teeth of Dogs

“…A commercially available ivorine maxillary fourth premolar tooth a was used to create models for 2 test groups: group A without axial grooves and group B with axial grooves as previously described. 8 The crown preparation design for both groups included a height reduction to 5 mm and standard axial wall reduction of 0.5 mm on all prepared axial walls. The CA of the ivorine maxillary fourth premolar (43 ; Figure 1) was maintained during axial wall reduction.…”

“…The most pertinent dimensions for crown retention are convergence angle (CA), crown height, and crown diameter. 8 The latter 2 dimensions may be viewed as the height to diameter ratio (H/D). Traditional prosthodontic references state that the ideal morphology for crown retention is a columnar shape with near parallel opposing axial walls (ie, CA < 12 ) and a large H/D.…”

“…[12][13][14][15][16] In vitro evaluation of the influence of axial grooves in the canine tooth revealed a significantly increased force required to dislodge full veneer crowns in the teeth that incorporated axial grooves compared to those teeth that did not incorporate axial grooves. 8 The purpose of the present study was to evaluate the influence of axial grooves on the dislodgment resistance of full veneer crowns of the maxillary fourth premolar tooth. We hypothesized that the addition of axial grooves to the crown preparation design of the maxillary fourth premolar teeth in dogs would increase resistance to dislodgment of cemented full veneer crowns compared to teeth prepared without axial grooves.…”