Introduction
The management of impacted, unerupted, or malpositioned mandibular second molars with orthodontic therapy requires special attention in order to achieve normal anatomic positioning within the dental arch. We present a surgical approach to managing these teeth combining exposure and surgically-assisted forced eruption.
Methods
This retrospective single-group cohort study followed 260 impacted mandibular second molars. The molars were exposed and surgically uprighted. An orthodontic bracket was bonded to aid in orthodontic traction, and the wound was packed to prevent soft tissue growth over the crown of the exposed molar. Patients were followed for a minimum of 6 months after uprighting, during which the following outcomes were measured: the degree of success of the eruption one the basis of the clinical occlusal relationship to the opposing dentition, radiographic evidence of bone fill, the periodontal status of the teeth involved, and tooth vitality.
Results
A total of 260 mandibular second molars were uprighted in 177 patients (83 female, 94 male) with an average age of 14.8 years. Outcomes showed that 255 molars (98.1%; 95% confidence interval, 96.3-99.8) were successfully uprighted. Complications included infection/abscess in 3 molars and fractured root requiring extraction in 2 molars. All remaining 255 teeth tested vital, 17 teeth had periodontal pocketing of more than 5 mm, and 235 of the teeth had occlusal contact after healing.
Conclusions
Surgically-assisted forced eruption with or without orthodontic forced eruption is a safe, successful, and viable approach to managing unerupted or malpositioned mandibular second molars in the adolescent population.
Highlights
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Surgically-assisted forced eruption is an option for unerupted mandibular second molars.
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Outcomes showed that 255 of 260 molars were successfully uprighted.
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Complications were rare and included infection, abscess, and root fracture.
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All 255 teeth were vital at follow-up.
Mandibular second molars are frequently malpositioned in the human dentition. The range of impaction has been reported to be between 0.6 and 10 teeth per 10,000 mandibular second molars. , , Although early detection and prediction may avoid these situations, there is no consensus on the timing of early intervention or the mechanisms to determine the likelihood that a second molar may remain malpositioned. Numerous reasons for these malpositions have been hypothesized, including decreased arch length and orthodontic manipulation through first molar distalization, leading to subsequent tipping of the second molar in a mesial-angular position. , There does not seem to be a strong agreement on the influence of the third molar in affecting the eruption of the second molar. ,
A review of the literature reveals numerous approaches to the management of this problem. Some authors focused on the extraction of the affected tooth or associated molars in order to create space in the arch. , Others have described methods to attach anchors or brackets to the teeth to expose them using orthodontic forced eruption. , To date, surgical management of this situation as described in the literature has primarily been focused on exposing the teeth (with or without the addition of bonding brackets), inserting dental pins, or the placement of miniscrews. In contrast, more authors have recently looked at the specific surgical manipulations to try to engage the molars into a proper occlusion , emulating some early literature describing the direct uprighting of affected second molars. ,
The 5 main categories in the scientific literature for the management of impacted mandibular second molars are (1) extraction of the offending second molar in the hopes that the third molar erupts or can be directed to erupt in the proper position, , , (2) extraction of the first molar if it is compromised, (3) exposure of the second molar only, (4) exposure with an orthodontic guided eruption of the second molar, , , , , and (5) surgical repositioning/uprighting of the second molar followed by orthodontic refinement of tooth position. ,
This study aimed to investigate the clinical outcomes of the surgical uprighting technique in the treatment of impacted mandibular second molars.
Material and methods
This study was designed to be a retrospective, single-group cohort study. All patients included were referred to our surgical clinic specifically for the management of an impacted second molar by a certified orthodontic specialist (over 5 years). Maxillary second molars were not evaluated in this study because the behavior of these impactions were different. , No other exclusion criteria were set for patients enrolled in this study. The second molars were all deemed unlikely to erupt by the referring orthodontist. All patients had a preoperative screening appointment, during which they received a panoramic radiographic and clinical examination confirming the presence of an impacted mandibular second molar.
Data collection for all patients included the following: age at the time of consultation, sex, orthodontic status, and position of the second and third molars. The second molar position was grossly documented as horizontal, lingual, or partially erupted—determined by a combination of clinical and radiographic evaluation using a panoramic radiograph. Teeth labeled as horizontal were defined as being positioned at an angulation approximately greater than 45° to the occlusal plane, teeth labeled as partially erupted had the crown positioned at approximately 45° or less to the occlusal plane, and teeth labeled a lingual had crowns tipped toward the lingual aspect of the dental arch at an angle approximately greater than 25°.
A treatment algorithm was created as follows: after confirming medical history, fasting status, escort, and consent, patients were placed in a supine position with the administration of 50% nitrous oxide, and intravenous access was obtained. Moderate sedation was applied to all patients and local anesthesia using 5-10 ml of 2% lidocaine with 1:100 000 epinephrine, which was infiltrated in the mandible. A preoperative dose of either 1 g of ampicillin or 600 mg of clindamycin was given intravenously before the start of the procedure. A full-thickness mucoperiosteal flap was incised and raised, exposing the second molar as well as the adjacent first molar’s cementoenamel junction. This incision was continued distolaterally beyond the retromolar pad. If overlying tissue covered the impacted second molar, then a generous gingivectomy was performed to expose the crown. If needed, a 701 bur was used for troughing around the crown of the impacted molar, and a small 301S dental elevator was used to luxate the second molar.
Between careful luxation, uprighting, and rotating the crown, the tooth was brought to the most coronal position possible. After uprighting, a minor occlusal reduction was performed as necessary to ensure that the opposing molar crown did not interfere, impede, or indeed push down the newly positioned second molar crown. The distal aspect of the socket was sometimes reduced to make room for the distally maneuvered crown. Once the best height was reached, the tooth was then stabilized with a small 5 × 10 mm sheet of surgicel in the mesial embrasure. This sheet acted as a wedge as well as aided in hemostasis. If the exposure of the second molar was inadequate for orthodontic access or manipulation, then a waxed gauze pack was placed for no more than 7 days with the placement of an orthodontic bracket to help hold the gauze in place. On occasion, the buccal soft tissue was positioned apically and maintained in place with sutures, tissue adhesives, or temporary anchorage devices (TADs). If the second molar was mobile, then a composite bridge was applied with or without a rigid 0.018 × 0.022-in stainless steel orthodontic wire joining the teeth together—this was then removed at 6 weeks. If the patient presented with orthodontic appliances in place, then either a bracket was placed (usually a prebonded tubed second molar bracket) or full exposure was ensured to allow the orthodontist to place a bracket postoperatively.
For most molars, no packing gauze was placed over the uprighted teeth to avoid the reduction of the tooth back into the socket. No postoperative antibiotics were provided, and all patients received oral 10 mg ketorolac and Tylenol no. 3 (20 tablets of 300 mg acetaminophen and 30 mg codeine phosphate; Janssen Pharmaceutica, Beerse, Belgium) for analgesia as needed. A panoramic film was taken of all patients before discharge. All surgical therapy was provided by 2 experienced surgeons (M.F.C and E.I.R).
All patients were followed for a minimum period of 6 months postsurgically. The clinical outcomes were evaluated using a panoramic radiograph and clinical examination, as well as periodontal, endodontic, and occlusal examinations. The following data were collected: (1) periodontal examination, including 6 probing depths for the second molar and noting whether there was bleeding on probing; (2) subjective radiographic assessment of the amount of alveolar bone regeneration around the roots of the uprighted teeth, noted as either adequate or poor, with adequate defined as evidence of bone fill that is subjectively consistent with expected bone fill by this follow-up period; (3) endodontic status, tested with the response to cold testing using ethyl alcohol spray on the second molar, noted as either positive or negative; (4) gross description of the final root development, based on the panoramic radiograph at follow-up and labeled as appearing normal or blunted; and (5) occlusal relationship with the opposing maxillary dentition, labeled as the presence or absence of any occlusal contact.
Treatment or surgical complications were documented independently. These included surgical infections, subperiosteal abscesses, root fractures, or loss of teeth (failure of uprighting).
Results
Of the 177 patients included in this study, the mean age was 14.5 years for females (standard deviation, 1.7 years) and 15.1 years for males (standard deviation, 2.2 years). All patients included in this study were otherwise relatively healthy, with no major systemic disorders. They had a total of 260 impacted mandibular second molars, and 226 of the associated third molars, or 86.9%, were removed. Orthodontic brackets were placed on 160 (61.5%) of the uprighted second molars. Of these, 5 of the molars had to be anchored to the adjacent molars because of significant mobility after the uprighting. A dressing was applied to 131 (50.4%) of the second molars to prevent the surrounding soft tissue from creeping over the crown of the affected tooth ( Table I ).
| Characteristics | n | % |
|---|---|---|
| Baseline (T1) | ||
| Molars (patients) | 260 (177) | |
| Mandibular left second molar | 134 | 51.5 |
| Mandibular right second molar | 126 | 48.5 |
| Males (age, y) | 94 (mean, 15.1; SD, 2.2) | 47.8 |
| Females (age, y) | 83 (mean, 14.5; SD, 1.7) | 52.2 |
| Intraoperative (T2) | ||
| Removal of associated third molar | 226 | 86.9 |
| Placement of a bracket | 160 | 61.5 |
| Mobility | 5 | 0.02 |
Examples of treated molars are shown in Figures 1 and 2 . Of the 260 second molars treated in this study, 5 teeth (1.9%) required removal after attempted surgical uprighting—3 of those because of infection/abscess (removed within the first month after operation), and 2 teeth were deemed failures because of fracture of the roots during uprighting. Four of these molars were from males aged 12-20 years (only 1 patient was aged >18 years). Three of these molars were partially impacted, 1 tooth was lingual, and 1 tooth was horizontally impacted.
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