Is there a difference between traditional and flapless corticotomy?

One of the most important challenges in orthodontic practice is prolonged treatment time, which leads to multiple side effects, such as dental caries, periodontal diseases, and root resorption. Several therapeutic procedures have been introduced to reduce orthodontic treatment duration, such as surgical interventions. It has been suggested to elevate flaps and perform corticotomy using surgical burs. Although traditional corticotomy proved to be effective in accelerating different types of tooth movement, it has been considered aggressive. Hence, minimally invasive surgical techniques that may offer similar clinical efficacy with the least possible trauma have been proposed, and such procedures have been labeled “flapless corticotomies,” (ie, surgical interventions without flap elevation). However, there are llimited clinical trials comparing the flapless corticotomy with the traditional corticotomy.

The following is one such article that compares flapless corticotomy with the traditional corticotomy associated with  en-masse retraction of maxillary anterior teeth in terms of speed, dentoalveolar, skeletal, and soft-tissue changes, and EARR.

‘The effectiveness of traditional corticotomy vs flapless corticotomy in miniscrew supported en-masse retraction ofmaxillary anterior teeth in patients with Class II Division 1malocclusion: A single centered,randomized controlled clinical trial’

Khlef HN, Hajeer MY, Ajaj MA, Heshmeh O, Youssef N, Mahaini L.

American Journal of Orthodontics and Dentofacial Orthopedics. 2020 Dec.

doi: 10.1016/j.ajodo.2020.08.008.

What did this paper assess?

The objectives of this randomized controlled trial were

(1) to investigate the effectiveness of traditional corticotomy and flapless corticotomy performed by piezosurgery in accelerating the en-masse retraction of maxillary anterior teeth,

(2) to compare the 2 corticotomy techniques in terms of the skeletal, dental, and soft-tissue changes, and

(3) to assess the amount of EARR at the 6 maxillary anterior teeth using digital panoramic radiographs.

What was the protocol?

This study was a single-centered, 2-arm parallel group randomized controlled clinical trial. Forty adult patients (36 female, 4 male) were equally and randomly divided into 2 groups: Flapless corticotomy group (FCG) (n = 20) and traditional corticotomy group (TCG) (n = 20). All patients fulfilled the following criteria:

(1) Age range between 18 and 30 years,

(2) Class II Division 1 malocclusion requiring maxillary first premolars extraction,

(3) mild to moderate skeletal Class II malocclusion,

(4) overjet >5mm and < 10 mm,

(5) normal or excessive anterior facial height,

(6) No or mild crowding (tooth size–arch length discrepancy ≤3 mm),

(7) Completion permanent dentition (regardless of third molars),

(8) no previous orthodontic treatment history,

(9) no systematic diseases or drug use that would affect bone and tooth movement rate, and

(10) good oral hygiene and healthy periodontium.


 Levelling and alignment.

The extraction of first premolars was performed for all patients at the beginning of the treatment, in order not to disturb the results of the applied corticotomy. All patients were treated with 0.022×0.028 inch Brackets. Self-drilling titanium miniscrews were inserted between the roots of maxillary second premolars and first molars bilaterally, at approximately 8-10 mm above the archwires at the mucogingival junction. Both the maxillary second premolar and first molar were linked to the miniscrew with ligature wire to ensure that no mesial movement of the posterior segments occurs during the leveling and alignment phase. To ensure the completion of the leveling and alignment phase, the last SS archwire (0.019 x 0.025-in stainless steel (SS)) was left for 3 weeks before starting the retraction process.

Surgical intervention.

Regional anesthesia was injected in the infraorbital foramen and incisive foramen (2% lidocaine HCl with 1:80,000 epinephrine).

Flapless corticotomy group

Two incisions were made between the maxillary canines and second premolars, and 1 incision was made between the roots of the 6 maxillary anterior teeth on the buccal and palatal gingiva(which can be considered as one of the strengths of the study) by using a BP blade. Next, a piezosurgery knife associated with an irrigation solution pump was inserted to perform the cortical alveolar incisions. No subsequent sutures were required because soft-tissue incisions were limited to the attached gingiva, and no periosteum dissection was performed.

Traditional corticotomy group

A full-thickness mucoperiosteal flap was elevated, including the interdental papilla, and extended from the distal side of the second premolar on the right side to the same position on the left side without making any vertical releasing incisions. The full-thickness flap was raised by the mucoperiosteal elevator. After this, 2 vertical cortical alveolar incisions in the place of first premolar extraction and 1 vertical incision between the roots of maxillary anterior teeth were made by the piezosurgery knife and the vertical incisions were joined by a horizontal incision. The flap was repositioned, and the surgical suturing was performed which was removed 7 days after corticotomy.

En-masse retraction

The en-masse retraction was initiated after 4 days of performing the corticotomy; 0.019 x 0.025-in SS archwires with 8-to-10-mm long soldered hooks distal to the lateral incisors were placed for all patients, and NiTi closed coil springs with a length of 9 mm were stretched from the soldered hooks to the miniscrews and applied 250 g of force per side. The generated force was checked using a force gauge. The patients’ follow-up appointments were every 2 weeks in order to take the maximum advantages of the RAP.

Outcome assessment

The duration of en-masse retraction in both corticotomy techniques was calculated from the first day on which NiTi springs were applied until the canines reached Class I relationship with normal overjet and overbite.

The skeletal, dental, and soft-tissue changes were assessed on the lateral cephalograms, which were digitally traced and measured.

The EARR was assessed on the digital panoramic radiographs.

What did their results show?

1. There was no significant difference between the 2 corticotomy techniques in terms of the skeletal, dental, and soft-tissue variables, and in the amount of EARR.

2. The en-masse retraction of maxillary anterior teeth in both groups resulted in improvements in skeletal structures and facial profile, retraction of maxillary anterior teeth, slight distal movement of first molars, and an intrusion movement of anterior and posterior teeth.

3. Neither corticotomy technique caused significant EARR.

Critical appraisal:

The efforts of the author to avoid smoking for one week after corticotomy and to forbid NSAIDs is appreciated. However, the effect of smoking after the one-week period and the effects of drugs other than NSAIDs were not considered. The environmental factors and nutritional deficiencies that may influence tooth movement were not considered. The status of the periodontal tissues was not assessed after the corticotomy procedure. The EARR was assessed on a two-dimensional radiograph. The focus of this study was oriented toward the maxilla only. This trial was conducted on a specific type of malocclusion with a specific age range and very strict inclusion criteria. Although a randomization was done the sample did not have equal no. of male and female participants. Blinding was neither applied to the investigator nor the patients during the trial.?

Conclusion and scope for future studies:

In the current analysis, there was no differentiation between the two corticotomy techniques. However, the responses in the mandible and the difference between the response in males and females needs to be evaluated further. In addition, there is a need to evaluate the periodontal tissues after corticotomy. The levels of perception of pain and discomfort and long-term complications such as teeth vitality should also be investigated in future research. Finally, more prospective clinical trials should be conducted on several populations with different treatment scenarios to have better generalizations.

Contributers: Dr.Mrithulaa.M.V. Dr.Nandita.K