Periodontal Procedures

William Wilcko, an orthodontist, and his brother, Thomas Wilcko, a periodontist, popularized surgical periodontal procedures to accelerate OTM. Corticotomies consist of perforations in the cortical bone over teeth being orthodontically moved in an effort to increase the inflammatory response.20 This procedure works by increasing the amount of inflammation and inflammatory markers in the area which also play a role in bone turnover, a concept known as Regional Acceleratory Phenomenon, or RAP. Animal studies show that corticotomy can accelerate OTM up to 2-4 times as soon as 2 weeks after the procedure.21,22 The inflammatory effect of corticotomies fades over time, so the inflammation should be taken advantage of early on.21 Histological evidence shows increases in the number of osteoclasts and in the activity of osteoclasts, fibroblasts, cementoblasts, and osteoblasts. These changes indicate an effect on both the bone forming and bone resorbing portions of the bone remodeling cycle.21 Teeth also experienced less undermining resorption, hyalinization and root resorption.22 A human study of corticotomy resulted in 28-33% faster forced eruption of an impacted canine compared to controls, with no adverse side effects on the periodontium.23 Long et al., in a systematic review, found that the use of corticotomies resulted in greater distances of tooth movement for up to four months.24 The use of corticotomies, often in conjunction with bone grafting, has been termed Periodontally Accelerated Osteogenic Orthodontics (PAOO), as shown in Figure 1. While the evidence indicates that the use of these surgical procedures may accelerate tooth movement, this effect is primarily seen in the first few months after while the inflammatory response is increased, and consists of lower levels of evidence.25 More research is needed to improve our understanding of the effects of these procedures.

Figure 1. Before and after using PAOO in conjunction with Invisalign® for expansion in the maxilla in an adult patient.
Initial photos before orthodontic treatment Treatment progress after 14 aligners used Treatment progress after first set of aligners

The procedure was used to improve periodontal support and accelerate treatment.
A. Initial photos show maxillary constriction, posterior crossbites, and lack of bone and gingival support buccal to the maxillary posterior segments.
B. Progress photos after fourteen aligners were used in the maxillary arch only over 8 weeks of treatment. These photos were taken just prior to impressions for first set of Additional Aligners.
C. Progress photos after first set of Additional Aligners in preparation for another set of Additional Aligners as a refinement.

Other, less invasive, variations of this technique used to accelerate OTM are corticision, showing an increase in bone formation,26 and piezopuncture, which can accelerate OTM up to 3.26 times.27 Biologically these procedures were shown to reduce the lag phase, decrease hyalinization, and increase bone resorption. Fiberotomy, the removal of the dento-gingival fibers around the crowns, has also been shown to OTM rate by increasing bone resorption.28 While the use of periodontal procedures is encouraging, it is important to recognize that animals have been the main model for studying their use. No studies have been conducted in humans to compare the treatment modalities to one another, and the majority of research evaluates the use of corticotomy, which is also the most invasive. More studies are needed to determine the most advantageous protocol for the purpose of accelerating OTM. The added disadvantage of increased cost of an additional procedure by a different specialist should also be considered,29 as well as the added risks such as infection and inflammation.

The PROPEL® system (Figure 2), used to make micro-osteoperforations in the cortical bone by the orthodontist, was recently found to close maxillary premolar extraction spaces via canine retraction 2.3 times faster. This system increases inflammatory markers, accelerating treatment by 62%, and allows for the orthodontic practitioner to do the procedure instead of needing to refer out to another specialist.30 Additional high level research is also needed to fully understand the effects of this with orthodontic treatment.

Figure 2. The PROPEL® system used to retract upper canines into extraction spaces after several months of attempted space closure.
PROPEL: initial photos before placement
A. Day that PROPEL® micro-osteoperforations were placed.
PROPEL: 8-weeks after placement
B. Eight weeks after. Left space is completely closed, right space has minor space remaining.