Maxillary Canine Impaction Managed using Non-Invasive Technique: The Fixed Anterior Push Sagittal Appliance

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Maxillary Canine Impaction Managed using Non-Invasive Technique: The Fixed Anterior Push Sagittal Appliance


Yashesh Sheth1* and  Kenneth Lee2

1Student, Fellow of the ICOI, Jaume I University, Perth, Australia

2Professor Universitat Jaume I, Castellon, BDS (Syd), MSc Oral Implantology (Goethe), MSc Orthodontics (Castellon),
FICD, FPFA, Private practice, Sydney, Australia 

*Corresponding author: Yashesh Sheth, Student, Fellow of the ICOI, Jaume I University, Perth, Australia.

Citation: Sheth Y, Lee K. (2023) Maxillary Canine Impaction Managed using Non-invasive Technique:  The Fixed Anterior Push Sagittal Appliance. J Oral Med and Dent Res. 4(1):1-16.

Received: May 10, 2023 | Published: June 1, 2023

Copyright© 2023 genesis pub by Sheth Y. CC BY-NC-ND 4.0 DEED. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non-Commercial-No Derivatives 4.0 International License., This allows others distribute, remix, tweak, and build upon the work, even commercially, as long as they credit the authors for the original creation.




Canine impactions/ ectopic canines are always challenging yet demanding to de-impact and most would require an interdisciplinary approach of combined surgical -orthodontic therapy or extraction if early intervention timing is missed.


This article presents cases with poor-average prognosis of maxillary canine erupting successfully using non-invasive technique for the practitioner and compliance free appliance for the patient: the fixed anterior push sagittal appliance.


Canine impaction is best diagnosed early to prevent its ectopic eruption. Patients and their helping clinicians would want to defer surgical intervention, damage adjacent teeth and prevent loss of that tooth. Canine impactions are always challenging yet demanding to deimpact and most would require an interdisciplinary approach of combined surgical orthodontic therapy or extraction if early intervention timing is missed. Mandibular 3rd molars are the most frequently impacted followed by canine impaction in the maxilla with approximately 2/3 being palatal [1,2].

Development of canine is critical in understanding normal eruption pattern. At age 4-5months canine calcification commences and is completed by age 5-6 years. It develops high in the maxilla, piriform fossae being lateral to it and approximately 22mm path of eruption – being the longest for any tooth. It then migrates downwards and forwards to be palpable around age 10 in the buccal sulcus. Female to male ratio is 7:3 with earlier eruption in females around ages 11-12 years [3,4]. Canine is considered impacted if unerupted after ¾ root formation, 6months or more of the contralateral tooth eruption and complete root formation. Or finally, canine position is still intra osseous at or beyond cervical stage 5 or 2 years post adolescent growth spurt or 6 months after its root development completion [5,6,7].

Aetiology of impacted canines is multifactorial related to environmental and genetic factors. Path of eruption is long and therefore boosts the likelihood of impaction. Obstructions in the path of eruption such as resistant to resorption of deciduous canine, presence of cysts, fibrous tissues, dense bone and supernumerary teeth. Arch length discrepancy from crowding or shortening of length can lead to buccal impaction [8]. Reported incidence of canine impaction is increased to 42.6% if lateral incisors are small or developmentally absent -since canine during its eruption takes guidance from roots of lateral incisors [9].  Stated palatal impactions are mostly due to the genetic reasons – common in some ethnic patients, females, twins and certain families [10]. 


Sequelae of an impacted canine is critical in understanding the significance of intervention in a timely manner. Some of these include labial or palatal mal-positioning of impacted tooth, migration of neighboring teeth and loss in arch length, external root resorption of impacted and neighboring teeth, loss of vitality of incisors, infections, cyst formation, referred pain, damage to adjacent teeth during surgery, poor esthetics with over retained primary canines, ankylosis and internal resorption of canine. Therefore, it is critical a systematic approach be used to diagnose and classify the degree of impaction and the use of least invasive technique to help de-impact the canine and minimize the possible side effects. The canine bulge palpation from age 8 onwards is the most common recommended diagnostic tool, however, lack of positive palpation if only considered abnormal after age 10. In addition, mobility and color of the deciduous canine should be visualized clinically [11]. Supplementation by radiographs using one or combination of panoramic, periapical radiographs, lateral cephalometric, occlusal radiographs and/ or CBCT or medical CT scans may be required to confirm the clinical diagnosis.  

Traditionally magnification technique was used which indicated palatal canines appear closer to source of x-ray and sensor is away from it.  However single image OPG overestimated angulation and proximity to midline is underestimated which is a major limitation of this technique and localization using parallax technique is preferred [12]. Parallax technique depends on tube-shift principle or Clark’s rule or SLOB: same lingual opposite buccal [3]. 2 types of parallax techniques – horizontal or vertical. Diagnostic accuracy of horizontal is shown to be superior to vertical by showing 88% diagnostic sensitivity for horizontal compared to vertical parallax technique [13]. 


Canine impaction classification first described by in both the frontal and transverse planes using axial vertex and panoramic radiograph [14, 15]. This was staged in 5 sectors shown in Figure 1.  

Figure 1: Canine impaction classification.
The above schematic illustration shows normalization of the maxillary permanent canine at the control 18 months after extraction of primary canines [14].
Since this classification several other classifications have been described in the literature. 
a. 4 sector classification by Lindauer [7].  
b. 3 sector classification by Dr Crescini (Crescini and colleagues, 2007) 
c. Sector classification by [1]. 
d. Alpha angle as predictors of severity of impacted canine – [15]- stated risk of root resorption of lateral incisor increased by 50% if angle greater than 25. 
e. Beta & gamma angle as predictors of severity of impacted canine – beta angle described as angle between long axis of impacted canine to long axis of lateral incisor adjacent to it. Again, noted angle greater than 54 was difficult to manage [15]. Have noted beta angle greater than 54 degrees having likelihood of root resorption is 61% or more. Therefore, root resorption predictability is substantially affected by beta angle [16]. 
f. Distance of canine’s crown from occlusal plane as predictors of severity of impacted canine as described by as the distance in mm from canine cusp tip to occlusal plane measured perpendicular [17]. Graded the canine impaction to adjacent incisor [1]. 
g. Position of canine root apex anteroposteriorly as predictors of severity of impacted canine as graded by [1].
There are various canine impaction classifications, and a simple approach would be to consider many of the above into a simple assessment, as the aim is to de-impact the canine with the least invasive treatment approach. Have simplified prognostic elements to be used in an index to assess and manage the severity of difficulty [18, 19, 1]. The pictorial series below describes the index [20], [Figure 2].

Figure 2: De-impact the canine with the least invasive treatment approach pictorial series of the index.

Management of impacted canines is critical, and the general dental practitioner is well positioned to identify early. Have previously shown early extraction of deciduous maxillary canine can allow to de-impact canine and allow erupt in the correct position, this has been further extended to cases that are class 1 non-crowded [15]. Improvement in positioning with interceptive extraction to more favorable position was also reported [21], [Figure 3].


Figure 3: Improvement in positioning with interceptive extraction to more favorable position.

Other options include do nothing (no active therapy) and monitor radiographically for any oral pathology like cysts, interceptive therapy – extraction of deciduous canine and expansion in the required dimension, surgical exposure and orthodontic therapy, surgical repositioning and extraction.

If timing for early intervention is lost and crowding or lack of space is noted, the need for multidisciplinary treatment arises and invasive therapy including surgery. Fixed anterior push sagittal appliance is a treatment modality which in current times has been advocated by Dr. Galella and the facial beauty institute (2023). They have recently modified the appliance to make it more hygienic and durable. It has been recommended to be used in patients over age 10 through adulthood to develop the naso-maxillary complex and upright the mandible ramus through remodeling. This appliance takes advantage of the remodelling occurring in the facial region by influencing residual growth sites. Based on the current understanding of Craniofacial Biology, it is imperative that clinical treatment should progress in the direction of [Figure 4]:

Biology, it is imperative that clinical treatment should progress in the direction of:  

Normal facial balance o Nasomaxillary complex o Mandibular position o Symmetry 

Stable Class I cuspid occlusion 

table Temporomandibular Joints 

And that the following be ideally achieved: 

Lip Seal (Competent lips and strong orbicularis oris) 

Nasal Breathing (Healthy airway) 

absence of Tongue Habits 

Figure 4: A: MX Fixed Anterior Growth Guidance Appliance, Facial Version Generation 8 MX Fixed Osseo-Restoration™ Appliance, Facial Version Generation 8. B: MX Fixed Anterior Growth Guidance Appliance, Facial Version MX Fixed Osseo-Restoration™ Appliance, Facial Version.

These three attributes shall be referred to as the “BIG 3”. It should be noted that the “BIG 3” represent more than just the three points indicated above. When achieving the “BIG 3” each patient is equalizing the complex forces of Craniofacial Biology including such factors as harmonious balance of extrinsic soft tissue influence, balanced growth, congruent function, and biological stability. 


Have reported the maxillary complex to be significantly shorter in the sagittal dimension for ectopic canines [22]. Dr Yosh Jefferson has presented Jefferson’s analysis that is presented as a cephalometric analysis that is health and face centered, which is used to enrich facial attractiveness and in turn balance in facial proportions which would allow improvement in variety of health issues. All cases presented below show maxillary retrognathism and developing the maxillary complex helps to de impact the ectopic canine and in addition facial proportions improved and supplemented by less stress for the clinician and suffering for the patient [23]. Average to poor prognosis canine impaction cases were successfully de-impacted using fixed maxillary anterior push sagittal appliance, also known as the CD advancer, maxillary fixed anterior growth guidance appliance and maxillary fixed osseo-restoration  case 1 to case 5 given below [Figure 5 to Figure 27].


Case 1: