OUTCOMES
Studies of outcome:
Depending where you look, the numbers vary a bit. Of course you don't really know any outcomes of the individual orthodontist, who don't report, but who treat and extract without any data being collected. The studies that collect data, you can presume, is made by practioners who are OK with giving out results.These are the teeth that are recorded, written up in papers, or getting a second opinion it would be interesting if all individual orthodontist had to report their results. It looks to me that if an orthodontist is extracting an impacted canine in a child/youth it is quite an exceptional event and it would be well worth recording what the ultimate reason is.
For children it looks as if basically 100% of impacted canines can be saved, but after the age 30 years or so, the success rate drastically drops.
'Palatally impacted canines: the case for preorthodontic uncovering and autonomous eruption" (1) recommends early preorthodontic uncovering of palatally impacted canines, so for a 10 or 11 year-old. It is also recommendes the treatment for adults. Interestingly, the article points out, in regards to adults:
A palatally displaced maxillary canine in a 35-year-old has been encased in bone for over 20 years. It is
highly likely that the tissue surrounding the root of that tooth will not be as responsive to autonomous
eruption immediately after uncovering as is typically seen in adolescents. This does not mean that the tooth
will not erupt. We believe that the surgical uncovering process signals the tissue surrounding the root to
gradually be transformed into a functioning periodontal ligament that will permit autonomous eruption with time. In fact, we have not encountered a tooth that would not erupt autonomously after uncovering,
even in adults.(1)
When impacted teeth get somewhere where there is interest enough to document, write case studies, and make
studies of outcome, the outlook for an impacted canine is relatively bright. An Irish study (2) showed that 96% of impacted canines with surgical intervention succeeded, another 2% succeeded with reoperation, and finally only 2% were lost.
- A study at University of Toronto, Canada (3), 1998, with 82 impacted maxillary canines in 54 patients, 12 to 16 years old, had all canines erupt successfully with exposure and bonding. Complications consisted of: failure of initial bond, at the time of surgery, which required rebonding; premature debonding at the time of pack removal and; debonding of brackets during orthodontic eruption. There was no infection, eruption failure, ankylosis, resorption or periodontal defect (pocket greater than 3 mm) associated with any of the exposed teeth. They did recommend that patients were treated before the age of 20 to ensure success.
- One study (4) with 80 patients (age 12-24, average 16) treated surgically and orthodontically, for 146 palatally bone impacted canines (so it seems the majority of patients had bilaterally impacted maxillary canines) had the following outcome: 70, 54% were successful, 43 canines (29 %) had to be extracted because of ankylosis.
- A study by Dr. Becker (3) of 19 adults (age 20-47, mean age 28.8) with 23 impacted maxillary canines was compared to a younger control group (age 12-16, mean age 13.7) with similar degree of difficulty. The success rate among the adults was 69.5% compared to 100% in the younger group. The failed canines were all in patients older than 30.
- 'Analysis of failure in the treatment of impacted maxillary canines' by Dr. Becker, a study
with 28 patients (age 17.4 +/- 4.3 years) and 37 teeth that were referred, showed that revised treatments had a success rate of 71.4%. (14). As for the reasons of initial failure the conclusion was:
Inaccurate 3-dimensional diagnosis of location and orientation of impacted teeth and failure to appreciate
anchorage demands were the major reasons for failure in the treatment of impacted canines. (p 743)(9)
This study proves to me that if an orthodontist is stumped, it is of the utmost importance that there is somewhere to refer patients, somewhere where a level of expertise and scientific curiosity is concentrated.
- 'Failure after closed traction of an unerupted maxillary permanent canine: Diagnosis and treatment planning' (10), shows again the importance of taking a second look at a case. A 13-year-old-girl had no effect of 6 months of traction, at renewed surgery,the chain appeared to be osseointegrated. With a new chain and 16 months of traction there was success.
Analysis of the causes for failure of the surgical - orthodontic treatment of impacted permanent canines - CT study' (11), relates the cases of 9 patients. 4 canines had to be extracted due to ankyolsis, some kind of blockage, or horizontal positioning. One failure was attributed to the formation of a 'periapical granuloma' where the authors speculated about its origin:
The cause of inflammation and the external resorption which were not present at the X-ray image
could be caused by indelicate surgical intervention and subsequent complicated healing, or that
the periapical granuolma is of nasal origin. (p.167)
They had 5 cases with success after intervention. One case sacrificed an incisor, moved the roots of adjacent teeth and made more space through varying degrees of manipulation.
(1) David P. Mathews, Vincent G. Kokich. Palatally impacted canines: The case for preorthodontic uncovering
and autonomous eruption. AJO-DO April 2013. Vol 143. Issue 4.
(2) http://www.dentist.ie/_fileupload/2009%2055%20No_%205%20-%20Oct%20Nov.pdf (p 24-28)(3) Bishara
SE. Clinical management of impacted maxillary canines. Semin Orthod 1998 Jun;4(2):87-98
(3) Caminiti et al. Outcomes of the Surgical Exposure , Bonding and Eruption of 82 Impacted Maxillary Canines.
J Can Dent Assoc. 1998 Sep;64(8):572-4,576-9.
(4) Robert L., Vanarsdall Jr., Efficient Management of Unerupted Teeth: A Time-Tested
Treatment Modality, Seminars in Orthodontics, Vol 16, No 3 (September), 2010:pp
212-221.
(8) Quintero J-C.'3-D imaging; the light in the attic', Ortho Tribune',
(5 ) Timothy J. Alford, W. Eugene Roberts, James K. Hartsfield Jr, George J. Eckert, and
Ronald J. Snyder (2011) Clinical outcomes for patients finished with the SureSmile™
method compared with conventional fixed orthodontic therapy. The Angle Orthodontist: May 2011, Vol. 81,
No. 3, pp. 383-388.doi: http://dx.doi.org/ 10.2319/071810-413.1
(6) Chaushu S, Chaushu G. Skeletal Implant Anchorage in the Treatment of Impacted Teeth -
A Review of the State of the Art. Seminars in Orthodontics, Vol 16, No 3 (September),
2010: pp 234-241.
(31) Oral and Maxillofacial Surgery. edited by Lars Andersson, Karl-Erik Kahnberg, Anthony Pogrel. 2010
(9) Becker A, Chaushu G, Chaushu S. Analysis of failure in the treatment of impacted canines, Am J Orthod
Dentofacial Orthop.2010 Jun; 137(6): 743-54.
(10) Frank Ch. Treatment options for impacted teeth. J Am Dent Assoc. 2007;131: 623-632.
(11) Cernochova P, Krupa P. Analysis of the causes for failure of the surgical - orthodontic treatment of
impacted permanent canines - CT study. Scripta Medica (BRNO) -78(3):161-170, August 2005. from
Faculty of Medicine, Masaryk University,Brno,Czeck Republic.
(21) Becker, A. Extreme Tooth Impaction and its Resolution. Seminars in Orthodontics, Vol 16, No 3
(September), 2010:pp 223.
and autonomous eruption. AJO-DO April 2013. Vol 143. Issue 4.
(2) http://www.dentist.ie/_fileupload/2009%2055%20No_%205%20-%20Oct%20Nov.pdf (p 24-28)(3) Bishara
SE. Clinical management of impacted maxillary canines. Semin Orthod 1998 Jun;4(2):87-98
(3) Caminiti et al. Outcomes of the Surgical Exposure , Bonding and Eruption of 82 Impacted Maxillary Canines.
J Can Dent Assoc. 1998 Sep;64(8):572-4,576-9.
(4) Robert L., Vanarsdall Jr., Efficient Management of Unerupted Teeth: A Time-Tested
Treatment Modality, Seminars in Orthodontics, Vol 16, No 3 (September), 2010:pp
212-221.
(8) Quintero J-C.'3-D imaging; the light in the attic', Ortho Tribune',
(5 ) Timothy J. Alford, W. Eugene Roberts, James K. Hartsfield Jr, George J. Eckert, and
Ronald J. Snyder (2011) Clinical outcomes for patients finished with the SureSmile™
method compared with conventional fixed orthodontic therapy. The Angle Orthodontist: May 2011, Vol. 81,
No. 3, pp. 383-388.doi: http://dx.doi.org/ 10.2319/071810-413.1
(6) Chaushu S, Chaushu G. Skeletal Implant Anchorage in the Treatment of Impacted Teeth -
A Review of the State of the Art. Seminars in Orthodontics, Vol 16, No 3 (September),
2010: pp 234-241.
(31) Oral and Maxillofacial Surgery. edited by Lars Andersson, Karl-Erik Kahnberg, Anthony Pogrel. 2010
(9) Becker A, Chaushu G, Chaushu S. Analysis of failure in the treatment of impacted canines, Am J Orthod
Dentofacial Orthop.2010 Jun; 137(6): 743-54.
(10) Frank Ch. Treatment options for impacted teeth. J Am Dent Assoc. 2007;131: 623-632.
(11) Cernochova P, Krupa P. Analysis of the causes for failure of the surgical - orthodontic treatment of
impacted permanent canines - CT study. Scripta Medica (BRNO) -78(3):161-170, August 2005. from
Faculty of Medicine, Masaryk University,Brno,Czeck Republic.
(21) Becker, A. Extreme Tooth Impaction and its Resolution. Seminars in Orthodontics, Vol 16, No 3
(September), 2010:pp 223.