Residents' journal review

Abstract

Primary failure of eruption (PFE) is a rare disorder that is described as cessation of eruption of the teeth. PFE is not caused by physical barriers, abnormal position of teeth, or a systemic condition. PFE often results in ankylosis of the affected teeth and open bite. This case report describes the treatment of an open bite caused by PFE and treatment with maxillary segmental distraction osteogenesis to improve occlusion and masticatory function. The 24-year old male patient presented with a Class III skeletal relationship and severe unilateral open bite caused by PFE. After 18 months of presurgical orthodontic therapy, mandibular setback surgery was completed to correct the mandibular prognathism. After 6 months, a 2--staged segmental osteotomy technique (palatal then buccal cuts) was applied, and an alveolar distractor was placed to achieve a gradual downward movement of the maxillary left segment. Four weeks of distraction were completed, and the distractor was removed. Subsequently, the authors used a “floating bone concept” to control the position of the alveolar segment after callus distraction, but before bone consolidation. This was accomplished via the use of intermaxillary elastics to move the dental segment into the desired position. Twenty-four months after treatment, panoramic radiographs showed successful vertical distraction osteogenesis of the alveolar bone and 8 mm closure of the open bite. The authors concluded that the “floating bone concept” is effective in improving a unilateral open bite caused by multiple ankylosed teeth. Reviewed by Shireen Irani and Azadeh Amin The goal of this review article was to evaluate the issues regarding the extraction of asymptomatic third molars. To date, health profession conferences have failed to reach a consensus for defined guidelines regarding the treatment of third molars. The American Association of Oral Maxillofacial Surgeons advocates the removal of asymptomatic third molars on the assumption that these sites are prone to future periodontal disease and a potential source of chronic inflammation. However, the evidence-based literature advocates monitoring asymptomatic third molars and does not support their extraction. First, there is no supporting evidence that mandibular third molars contribute to mandibular incisor crowding. In addition, there is little justification for the removal of asymptomatic third molars to prevent future complications such as odontogenic tumors, cysts, and mandibular fractures. Finally, periodontal pockets of 4 mm or greater involving the third molars do not necessarily initiate systemic health concerns involving a link between periodontal and cardiovascular diseases. Cardiovascular disease has been shown to have a stronger correlation with obesity, diet, age, sex, smoking, and family history. Extraction of unerupted, pathology-free, asymptomatic third molars is an elective procedure that should be performed based on the patient's ability to maintain good oral hygiene while considering the risks of nerve injury, infection, bleeding, and trismus associated with the procedure. The patient must be involved in the decision-making process and should be aware of these potential complications before consenting to the procedure. The authors believe that orthodontists should only recommend extractions if they are pertinent to orthodontic treatment. If the general dentist advises that a patient have extractions, then the orthodontist is safe from liability as long as no nonevidence-based referrals are made. Reviewed by Christopher Ruth and Kyle Jamison Although not too common a practice in the United States, autotransplantation of teeth can be a viable treatment to replace missing or nonrestorable teeth. Studies have shown that successful autotransplantation is best accomplished when root development of the donor tooth is two-thirds complete. Recent studies have shown successful transplantation of teeth with fully formed roots with success rates of 96% and 84% at 1 and 5 years, respectively. Many factors affect the outcome of autotransplantation; the most important is the maintenance of a healthy periodontal ligament of the donor tooth. Any steps that can be taken to reduce damage to the periodontal ligament during extraction should, in theory, lead to increased success. The authors suggested that orthodontic force applied to donor teeth before transplantation will widen the periodontal ligament, making atraumatic extraction more likely. The authors described 2 case reports in which successful autotransplantation was performed. In both cases, third molars were transplanted to a second molar site. On both third molars, orthodontic force was applied before extraction. In the first case, an uprighting spring was used; in the second case, a removable appliance with a magnetic force system was applied. Orthodontic forces were applied for 4 to 5 weeks. The applied forces were measured and reported to not exceed 30 cN. The Periotest (Siemens, Bensheim, Germany) was used to evaluate mobility. In both cases, mobility increased by more than 10 units. Subsequently, the teeth were transplanted, and antibiotics and nonsteroidal anti-inflammatory drugs were prescribed after surgery. Root canals were performed within 2 weeks of transplantation. Both cases showed success at 1 year postoperatively with no clinical or radiographic signs of transplant failure. The authors suggested that applying orthodontic force before autotransplantation might improve success rates. Reviewed by Adam Armstrong and Astrid Tourné Anchorage control is often critical when treating nongrowing Class II Division 1 malocclusions. In this retrospective study, the differences in tooth movement between conventional orthodontic anchorage vs mini-implant anchorage were analyzed using 3-dimensional virtual model superimposition. The conventional anchorage group consisted of 12 patients treated with headgear or a transpalatal arch, whereas the implant group consisted of 12 patients using mini-implants placed buccally in the maxilla between the second premolars and the first molars. All patients had full-cusp Class II Division 1 malocclusions that were treated with maxillary first and mandibular second premolar extractions. To reduce the impact of growth on the treatment outcome, the minimum pretreatment ages for girls and boys were 14 and 17 years, respectively. All patients were treated with a 0.022-in MBT prescription with sliding mechanics on 0.019 × 0.025-in stainless steel wire for space closure. En-masse retraction of the anterior segment was used. Spaces in the implant group closed significantly faster than did those in the conventional group (8.7 and 9.8 months, respectively). Compared with the conventional group, the implant group displayed greater distal displacement and intrusion of the anterior teeth. The posterior teeth moved mesially less in the implant group. There was also less contraction and mesial in-rotation of the posterior teeth in the implant group. In terms of angular measurements, there was more lingual inclination of the anterior segment in the implant group but no differences in mesial tipping of molars between the 2 groups. The intercanine width increased in both groups, but less decrease of intermolar width was observed in the implant group. The authors concluded that mini-implants can be used to minimize anchorage loss, molar rotation, and arch dimensional changes during en-masse retraction of the maxillary anterior teeth. Reviewed by Michelle Furlong and Vasilis Charalabakis When maxillary lateral incisors are congenitally absent, 3 treatment approaches are commonly considered: space closure and canine substitution, space opening and placement of an endosseous dental implant, and space opening followed by a tooth supported restoration. Replacement with an endosseous dental implant is considered a desirable approach, especially when the adjacent teeth are healthy and unrestored. However, this approach requires a sufficient amount of alveolar bone to ensure that the dental implant is placed in an optimal position. Previous authors have suggested that orthodontic movement of adjacent teeth through the edentulous alveolar ridge can develop adequate alveolar ridge dimensions, obviating the need for bone grafting. The purpose of this retrospective study was to evaluate the dimensional changes of the alveolar ridge in patients with congenitally missing maxillary lateral incisors who underwent treatment to open the space for an implant. The depth of the buccal concavity, alveolar bone width, and alveolar bone height were measured at 45 sites on 31 stone maxillary casts. Mean pretreatment and posttreatment measurements were calculated and analyzed using the Student paired-sample t test. Two methods were used to calculate the alveolar bone width. The results of method 1 showed a 4% to 8% decrease in ridge width, and method 2 showed a 13% to 15% decrease. The loss of ridge height was found to be 6% to 12%. The buccal concavity doubled in size from 0.5 mm at pretreatment to 1.0 mm at posttreatment. These changes were statistically significant. The authors concluded that since there is a significant decrease in alveolar ridge height and width after space opening, the available bone might not be sufficient for ideal placement of an endosseous implant without grafting. Reviewed by Christopher Baker and Daniel Breha Congenitally missing maxillary lateral incisors is a common problem in orthodontics. The purpose of this systematic review was to evaluate the efficacy of 3 treatments associated with the management of congenitally missing maxillary lateral incisors. These treatments include canine substitution, replacement with a fixed bridge, and replacement with a single-unit endosseous implant. These authors attempted to include randomized controlled trials of women over 15 years and men over 21 years of age who received one of the aforementioned treatments. The research followed the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions. The studies found included 347 from EMBASE, 249 from LILACS, 204 from BBO, 23 from MEDLINE, and 1272 from CENTRAL databases. The reviews were evaluated by 2 observers who found different degrees of bias found among them. No randomized controlled trials were found, and no articles were eligible because of their biases: eg, lack of random allocation, lack of blinding, and other problems. Much of the evidence reported was extracted from case reports and narrative reviews; however, no reliable agreement was found between the conclusions. The clinical implication of this study is that without scientific evidence from randomized controlled trials, clinicians should exercise extra caution when treating patients with agenesis of maxillary lateral incisors, contingent upon their skills and experience. The review affirmed that there is currently no conclusive evidence regarding any of the treatments. These issues require further scientific study to determine whether questions regarding the efficacy and safety of treatment methods for congenitally missing maxillary lateral incisors are to be answered. The authors stressed that future research should be aimed at conducting randomized controlled trials to offer additional clinical decision-making support for orthodontists. Reviewed by Eniko Toth and Colleen Mohan The retrieval of impacted teeth is a common challenge faced by orthodontists. The purpose of this article was to describe several adjustable force systems that can be used to quickly retrieve impacted teeth from various locations in the mouth. The authors pointed out that it is important that any retrieval force system must have a force vector that is adjustable in all 3 planes of space and also delivers a constant level of biological force that would not decay as the impacted tooth moved. The first system, a maxillary lingual arch with an adjustable soldered eyelet, redirects palatal impacted canines via elastic ligature traction from the impacted canine through the eyelet to a banded molar. A second type of device for retrieval involves an 0.018 × 0.018-in stainless steel or beta-titanium buccal cantilever that guides the impacted maxillary canines occlusally into place using a double helix spring system. This system uses traction via a precise vector dictated by the orientation of the mesial and distal helices as well as the length and the angulation of the cantilever arm. The next method is the lingual coiled cantilever, used for controlled extrusion of impacted anterior teeth and premolars. In this system, a 0.016-in wire is soldered to a lingual arch and then wound around the arch many times to form a spring with a terminal helix, which is then ligated to the impacted tooth. This force system is particularly useful when a completely vertical force is necessary. The final force system is useful for distal tipping of mesially impacted second molars. This device uses a distal vector strut ligated to a mesially bonded custom eyelet with an uprighting force delivered by a nickel-titanium activating spring. Each of the force systems presented by the author is an efficient and effective method for recovering impactions. However, care should be taken when selecting specific techniques indicated for each situation, since custom modifications are often needed on a case-by-case basis. Reviewed by Evmorfia Fotakidou and Chelesa Phillips