Incisive canal remodelling following maximum anterior retraction reduces apical root resorption

Abstract

Maximum retraction of the anterior teeth with premolar extraction is necessary to improve occlusion and facial aesthetics in patients with lip protrusion or severe skeletal/dental discrepancies. The application of temporary anchorage devices (TADs) has improved the efficiency and the predictability of 3-dimensional management of tooth movement and anchorage control; thus, incorporating TADs in comprehensive treatment, especially for premolar extraction cases, is well-accepted in clinical orthodontics. 1

Proximity of upper central incisors to incisive canal among subjects with maxillary dentoalveolar protrusion in various facial growth patterns:

“…A recent clinical study 12 had significant and shocking results, in which 53% of the cases that underwent maximum retraction showed IC invasion with grade 3 root resorption. The amount of root resorption was significantly higher with IC invasion than without invasion (2.39 mm vs 0.82 mm, P , .0001).…”

“…As a result, different degrees of root resorption were observed with an average of 2.39 mm, and the largest degree of invasion demonstrated 6.2 mm of root resorption. 12 ''The safety zone'' of orthodontic retraction may be less than traditionally thought. Most previous studies 11,13 identified the IC opening (incisive foramen) as the lowest point of the IC palatal wall rather than the buccal wall, which was presented in the study by Pan and Chen.…”

The Shape of Nasopalatine Canal as a Determining Factor in Therapeutic Approach for Orthodontic Teeth Movement—A CBCT Study

“…As previously reported [ 41 ], those morphometric parameters could be of clinical relevance for the interventions in the anterior maxilla, such as implant placement. However, morphometric analyses, such as those performed in this study, could also influence other clinical aspects, since it has been shown that the increase in NPC width (M-L IF) was accompanied by higher prevalence of NPC perforation during maximum central incisors retraction [ 20 , 22 ]. Furthermore, the enhancement of ML-IF diameter can also be addressed for subsequent complications, such as orthodontically induced inflammatory root resorption [ 12 , 27 , 50 ].…”

“…In conclusion, it seems that the increase in M-L IF, A-P IF, A-P NF, and NPC length in funnel-shaped NPC may be a risk factor for the interventions that could result in teeth movement. Literature data offer only the evidence that M-L diameter (NPC width) may contribute to adverse events accompanying orthodontic procedures [ 22 , 39 ].…”

“…Thus, Yu and collaborators noted that root retraction above 4 mm resulted in NPC invasion in 54% of patients [ 21 ]. Furthermore, Chung and coworkers [ 22 ] found a direct correlation between the degree of NPC invasion and severity of root resorption (the largest degree of NPC invasion presented at 6.2 mm of root resorption). Root resorption causes root shortening [ 23 ] and the consequence of this complication is manifested as tooth mobility [ 24 ].…”