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Maxillary molar mesialization with the use of palatal mini-implants for direct anchorage in an adolescent patient

2019; Elsevier BV; Volume: 155; Issue: 5 Linguagem: Inglês

10.1016/j.ajodo.2019.01.011

1097-6752

Benedict Wilmes, Sivabalan Vasudavan, Dieter Drescher,

Dental Implant Techniques and Outcomes

•Mini-implants can help minimize anchorage loss when mesial molar movement is needed.•With direct anchorage via the use of palatal implants, orthodontic brackets can be avoided•This reduces the risk of enamel decalcification and the potential for root resorption.•Space closure can begin immediately, bypassing the need for alignment and levelling. A unique clinical challenge presents when dealing with a compromised first permanent molar. A compelling treatment option for consideration is the removal of a nonrestorable first permanent molar, with the subsequent "replacement" through controlled mesial tooth movement of viable second and third molars. To reinforce the anchorage support associated with such a planned movement, indirect or direct implant-supported mechanics may be used. With the use of direct anchorage, orthodontic brackets are not required and space closure can be commenced immediately. In this article, we report the clinical procedure and design of direct-anchorage mechanics used for the successful closure of a maxillary first permanent molar space with the use of an implant-supported appliance (Mesialslider). Treatment was completed in just under 12 months, with successful mesial movement of the maxillary second and third molars without the need for the bonding of orthodontic brackets on the anterior dentition. The result was determined to be stable over a 3-year period. A unique clinical challenge presents when dealing with a compromised first permanent molar. A compelling treatment option for consideration is the removal of a nonrestorable first permanent molar, with the subsequent "replacement" through controlled mesial tooth movement of viable second and third molars. To reinforce the anchorage support associated with such a planned movement, indirect or direct implant-supported mechanics may be used. With the use of direct anchorage, orthodontic brackets are not required and space closure can be commenced immediately. In this article, we report the clinical procedure and design of direct-anchorage mechanics used for the successful closure of a maxillary first permanent molar space with the use of an implant-supported appliance (Mesialslider). Treatment was completed in just under 12 months, with successful mesial movement of the maxillary second and third molars without the need for the bonding of orthodontic brackets on the anterior dentition. The result was determined to be stable over a 3-year period. The first permanent molar is the tooth most frequently lost to dental caries or periodontal disease.1Moyers R.E. Handbook of orthodontics. Year Book Medical Publishers, Chicago1966Google Scholar Although there are a number of prosthetic options readily available for tooth replacement, orthodontic space closure by controlled mesial movement of the second and third permanent molars may be preferable and mitigates the need for ongoing restorative maintenance.2Baik U.-B. Chun Y.-S. Jung M.-H. Sugawara J. Protraction of mandibular second and third molars into missing first molar spaces for a patient with an anterior open bite and anterior spacing.Am J Orthod Dentofacial Orthop. 2012; 141: 783-795Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 3Nagaraj K. Upadhyay M. Yadav S. Titanium screw anchorage for protraction of mandibular second molars into first molar extraction sites.Am J Orthod Dentofacial Orthop. 2008; 134: 583-591Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 4Kyung S.H. Choi J.H. Park Y.C. Miniscrew anchorage used to protract lower second molars into first molar extraction sites.J Clin Orthod. 2003; 37: 575-579PubMed Google Scholar, 5Roberts W.E. Nelson C.L. Goodacre C.J. Rigid implant anchorage to close a mandibular first molar extraction site.J Clin Orthod. 1994; 28: 693-704PubMed Google Scholar A complex biomechanical challenge exists when protraction of the molars is required without retraction of the anterior teeth and premolars. Anchorage control is crucial in the treatment of such patients because lingual tipping of the incisors must be prevented while protracting the second and third molars. Titanium mini-implants are commonly used as a source of absolute anchorage during various types of tooth movement, because they are simpler, more cost-effective, and more convenient to use than endosseous implants.6Costa A. Raffainl M. Melsen B. Miniscrews as orthodontic anchorage: a preliminary report.Int J Adult Orthodon Orthognath Surg. 1998; 13: 201-209PubMed Google Scholar, 7Freudenthaler J.W. Haas R. Bantleon H.P. Bicortical titanium screws for critical orthodontic anchorage in the mandible: a preliminary report on clinical applications.Clin Oral Implants Res. 2001; 12: 358-363Crossref PubMed Scopus (147) Google Scholar, 8Melsen B. Costa A. Immediate loading of implants used for orthodontic anchorage.Clin Orthod Res. 2000; 3: 23-28Crossref PubMed Scopus (204) Google Scholar, 9Wilmes B. Fields of application of mini-implants.in: Ludwig B. Baumgaertel S. Bowman J. Innovative anchorage concepts. Mini-implants in orthodontics. Quintessenz, Berlin and New York2008: 91-122Google Scholar, 10Kanomi R. Mini-implant for orthodontic anchorage.J Clin Orthod. 1997; 31: 763-767PubMed Google Scholar The most frequently reported site for insertion and placement of these mini-implants is the buccal dentoalveolar region which can potentially be in the path of moving teeth. Therefore, particularly in the maxilla, the anterior palatal area seems advantageous, because all of the teeth can be moved without any interference from the mini-implants.11Ludwig B. Glasl B. Bowman S.J. Wilmes B. Kinzinger G.S. Lisson J.A. Anatomical guidelines for miniscrew insertion: palatal sites.J Clin Orthod. 2011; 45: 433-441PubMed Google Scholar Other considerations that make the anterior palate a preferred site for implant placement includes good bone quality, a thin attached mucosa, minimal risk of tooth injury, and a high associated success rate.12Lim H.J. Choi Y.J. Evans C.A. Hwang H.S. Predictors of initial stability of orthodontic miniscrew implants.Eur J Orthod. 2011; 33: 528-532Crossref PubMed Scopus (42) Google Scholar, 13Kim Y.H. Yang S.M. Kim S. Lee J.Y. Kim K.E. Gianelly A.A. et al.Midpalatal miniscrews for orthodontic anchorage: factors affecting clinical success.Am J Orthod Dentofacial Orthop. 2010; 137: 66-72Abstract Full Text Full Text PDF PubMed Scopus (64) Google Scholar To reinforce anchorage with the use of mini-implants, direct or indirect mechanics can be applied. In indirect anchorage treatment strategies, one tooth or many teeth are stabilized with the use of a rigid orthodontic wire, with an adjunctive full multibracket appliance needed. In contrast, the use of mini-implants with direct anchorage concepts involve forces being directly applied to the teeth that are to be moved. Considerations that may favor direct over indirect anchorage approaches include a possible esthetic advantage if concomitant orthodontic bracket placement is not required. A further corollary of such an approach is the reduced friction within the system, leading to treatment objectives being achieved over a shorter period of time. Furthermore, direct anchorage bypasses the initial alignment and leveling period associated with most conventional straight-wire systems, with the immediate commencement of space closure. In the present paper, the clinical procedure and design of direct anchorage mechanics for maxillary space closure with the use of 2 palatal mini-implants (Mesialslider) are described. A 17-year-old adolescent female patient presented with the absence of the maxillary first permanent molars. She was seeking orthodontic treatment to facilitate mesial movement of the maxillary second and third molars (Fig 1). Both maxillary first molars were lost because of periodontitis and nonrestorable decay. The patient reported that she had previously undergone a comprehensive course of orthodontic treatment, and she presented with an Angle Class I occlusion sound buccal intercuspidation. Her malocclusion was characterized by minor incisor irregularity, and mild mandibular arch-length insufficiency was noted. The panoramic radiograph confirmed the presence of the unerupted maxillary third molars, the periapical periodontitis of the upper right first molar, and a mucous retention cyst noted in the maxillary left sinus. The functional assessment of the occlusion did not show a discrepancy between centric occlusion and centric relation. There were no signs or symptoms of temporomandibular dysfunction. After extensive discussion with the patient and her parents, informed consent was obtained to proceed with a program of orthodontic care to protract the maxillary second molars and close the residual extraction spaces in the first permanent molar site. Alternative treatment approaches that were also considered were the use of removable or fixed prosthesis options, osseointegrated implants, and autotransplantation of the third molars. Although such alternative treatment approaches may be readily delivered with relatively shorter treatment times, they involve invasive surgical procedures (dental implants, autotransplantation) or are potentially biologically costly, often involving significant tooth preparation (fixed prosthesis). Variable long-term survival rates and complications of the alternate prosthetic and surgical options have been reported.14Pjetursson B.E. Brägger U. Lang N.P. Zwahlen M. Comparison of survival and complication rates of tooth-supported fixed dental prostheses (FDPs) and implant-supported FDPs and single crowns (SCs).Clin Oral Implants Res. 2007; 18: 97-113Crossref PubMed Scopus (572) Google Scholar, 15Josefsson E. Brattström V. Tegsjö U. Valerius-Olsson H. Treatment of lower second premolar agenesis by autotransplantation: four-year evaluation of eighty patients.Acta Odontol Scand. 1999; 57: 111-115Crossref PubMed Scopus (49) Google Scholar The patient made an informed decision to proceed with a treatment program involving closure of the residual maxillary arch spacing through the advancement of the maxillary second molars. Further consideration was given for the potential favorable eruption of the maxillary third molars into the original second molar position. The treatment objectives consisted of type C anchorage requirements, in which more than 75% of the residual space needed to be closed by the forward movement of the posterior segments through the mesialization of the maxillary second molars. A Mesialslider (1.1 mm stainless steel wire) connected to 2 median palatal mini-implants (anterior 2 × 11 mm, posterior 2 × 9 mm; Benefit System, PSM North America), as reported previously by Wilmes et al,16Wilmes B. Beykirch S. Ludwig B. Becker K. Willmann J. Drescher D. The B-Mesialslider for noncompliance space closure in cases with missing upper laterals.Semin Orthod. 2018; 24: 66-82Abstract Full Text Full Text PDF Scopus (4) Google Scholar, 17Wilmes B. Drescher D. A miniscrew system with interchangeable abutments.J Clin Orthod. 2008; 42: 574-580PubMed Google Scholar, 18Wilmes B. Drescher D. Nienkemper M. A miniplate system for improved stability of skeletal anchorage.J Clin Orthod. 2009; 43: 494-501PubMed Google Scholar, 19Wilmes B. Nienkemper M. Nanda R. Lubberink G. Drescher D. Palatally anchored maxillary molar mesialization using the mesialslider.J Clin Orthod. 2013; 47: 172-179PubMed Google Scholar, 20Wilmes B. Katyal V. Willmann J. Stocker B. Drescher D. Mini-implant-anchored Mesialslider for simultaneous mesialisation and intrusion of upper molars in an anterior open bite case: a three-year follow-up.Aust Orthod J. 2015; 31: 87-97PubMed Google Scholar was planned for the maxillary arch as a source of direct anchorage (Fig 2). Other mini-implant systems with abutments may be used as well (eg, OrthoEasy Pal, Forestadent).21Ludwig B. Zachrisson B.U. Rosa M. Noncompliance space closure in patients with missing lateral incisors.J Clin Orthod. 2013; 47: 180-187PubMed Google Scholar Treatment commenced with the insertion of the 2 palatal mini-implants, under local anesthesia, distal to the third palatal rugae (T-zone).22Wilmes B. Ludwig B. Vasudavan S. Nienkemper M. Drescher D. The T-zone: median vs paramedian insertion of palatal mini-implants.J Clin Orthod. 2016; 50: 543-551PubMed Google Scholar Stainless steel circumferential bands were cemented to the maxillary second molars, and an impression was recorded at the same appointment for laboratory fabrication of the Mesialslider. For this purpose, impression caps and laboratory analogs were used. Several days later, the Mesialslider appliance was fitted and engaged to the maxillary second molars (Fig 3). No brackets were bonded. Mesialization of maxillary molars commenced bilaterally with the application of a nickel-titanium closing coil spring (200 g). Over the next 6 months, approximately one-half of the first permanent molars space was closed, and elastic chains were then added to maintain the necessary mesialization force to facilitate continued space closure (Fig 4). Twelve months after the commencement of treatment, the bilateral spaces were closed and the planned mesial tooth movement of the maxillary left second molars was achieved (Fig 5), and the Mesialslider was removed (Figs 6 and 7). A vacuum-formed stent was prescribed for retention.Fig 3A, Mesialslider adapted on a plaster model. B, Intraoral photograph after placement of palatal mini-implants and the Mesialslider. C, D, radiographs after placement.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig 4Progress occlusal photographs after 6 months; elastic chains were added.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig 5Occlusal photograph after 12 months, at the end of treatment.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig 6Posttreatment extraoral and intraoral photographs, after removal of the Mesialslider.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig 7Posttreatment lateral cephalogram and panoramic radiograph after removal of the Mesialslider.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The planned treatment objective of maxillary space closure without concomitant anchorage loss was achieved. The maxillary third molars moved forward autonomously secondary to the pull of the interdental periosteal fibers. The chosen biomechanical approach enabled the line of force action to be applied closer to the center of resistance of the maxillary second molars, thereby achieving space closure predominantly through translation, or bodily tooth movement. The posttreatment panoramic radiograph (Fig 7) showed bodily mesialization of the maxillary second and third molars into the first molar spaces and sound alveolar bone levels. The superimposition of pre- and posttreatment 3D scans (superimposed on the palatal rugae23Becker K. Wilmes B. Grandjean C. Vasudavan S. Drescher D. Skeletally anchored mesialization of molars using digitized casts and two surface-matching approaches: analysis of treatment effects.J Orofac Orthop. 2018; 79: 11-18Google Scholar) showed the mesialization of both second and third molars (Fig 8). The posttreatment retention review was completed 3 years after the treatment was finished, and records demonstrated good stability of the dental movements. The small space between the maxillary right second and third molar disappeared owing to a final mesial drift of the third molar (Figs 9 and 10).Fig 9Superimposition of the pretreatment and posttreatment lateral cephalograms.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Fig 10Intraoral photographs after 3 years in retention.View Large Image Figure ViewerDownload Hi-res image Download (PPT) There has been a plethora of published cases and clinical studies recently describing the mesialization of second and third molars into the space of missing first molars.2Baik U.-B. Chun Y.-S. Jung M.-H. Sugawara J. Protraction of mandibular second and third molars into missing first molar spaces for a patient with an anterior open bite and anterior spacing.Am J Orthod Dentofacial Orthop. 2012; 141: 783-795Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar, 3Nagaraj K. Upadhyay M. Yadav S. Titanium screw anchorage for protraction of mandibular second molars into first molar extraction sites.Am J Orthod Dentofacial Orthop. 2008; 134: 583-591Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 4Kyung S.H. Choi J.H. Park Y.C. Miniscrew anchorage used to protract lower second molars into first molar extraction sites.J Clin Orthod. 2003; 37: 575-579PubMed Google Scholar, 19Wilmes B. Nienkemper M. Nanda R. Lubberink G. Drescher D. Palatally anchored maxillary molar mesialization using the mesialslider.J Clin Orthod. 2013; 47: 172-179PubMed Google Scholar, 24Holberg C. Winterhalder P. Holberg N. Wichelhaus A. Rudzki-Janson I. Indirect miniscrew anchorage: biomechanical loading of the dental anchorage during mandibular molar protraction—an FEM analysis.J Orofac Orthop. 2014; 75: 16-24Crossref PubMed Scopus (12) Google Scholar, 25Uribe F. Janakiraman N. Fattal A.N. Schincaglia G.P. Nanda R. Corticotomy-assisted molar protraction with the aid of temporary anchorage device.Angle Orthod. 2013; 83: 1083-1092Crossref PubMed Scopus (13) Google Scholar, 26Jacobs C. Jacobs-Müller C. Luley C. Erbe C. Wehrbein H. Orthodontic space closure after first molar extraction without skeletal anchorage.J Orofac Orthop. 2011; 72: 51-60Google Scholar However, our treatment mechanics was unique from previously reported cases, because there is no need for brackets if a direct anchorage–based mechanism is used. In this case, the mini-implants used had dimensions of 2 × 11 mm anteriorly and 2 × 9 mm posteriorly. Recently published cone-beam computed tomographic studies revealed that a length of 9 mm is sufficient to serve as anchorage in the anterior palate.27Hourfar J. Ludwig B. Bister D. Braun A. Kanavakis G. The most distal palatal ruga for placement of orthodontic mini-implants.Eur J Orthod. 2015; 37: 373-378Crossref PubMed Scopus (11) Google Scholar, 28Hourfar J. Kanavakis G. Bister D. Schatzle M. Awad L. Nienkemper M. et al.Three dimensional anatomical exploration of the anterior hard palate at the level of the third ruga for the placement of mini-implants—a cone-beam CT study.Eur J Orthod. 2015; 37: 589-595Crossref PubMed Scopus (26) Google Scholar The framework for the Mesialslider appliance (Fig 2, H) is readily available and allows for the Mesialslider to be adapted and manipulated at chairside. This potentially removes the need for laboratory support and its associated costs. However, depending on the experience of the operator, chairside adjustments may require additional clinical time. Alternatively, an impression or scan and adaptation of the Mesialslider on a plaster model might prove to be more practical. Figure 2 illustrates the mesialization system and its constituent parts for individualization in differing anchorage requirements. Although in our case we soldered part K directly to the maxillary molar bands, as shown in Figure 3, A, part L can be inserted directly into a standard molar band sheath chairside and does not require a laboratory soldering procedure. Our clinical experience has revealed that associated molar tipping can be prevented absolutely if the connection is as rigid as possible through the use of a soldered connector (Fig 2, K). In our case, the maxillary second and third molars were moved anteriorly into alveolar ridges with previous bone loss. Both nonhuman29Lindskog-Stokland B. Wennström J.L. Nyman S. Thilander B. Orthodontic tooth movement into edentulous areas with reduced bone height. An experimental study in the dog.Eur J Orthod. 1993; 15: 89-96Crossref PubMed Scopus (47) Google Scholar and human30Lindskog-Stokland B. Hansen K. Ekestubbe A. Wennström J.L. Orthodontic tooth movement into edentulous ridge areas—a case series.Eur J Orthod. 2013; 35: 277-285Crossref PubMed Scopus (27) Google Scholar experiments have shown that when a tooth is mesialized into a reduced bony ridge, the periodontal apparatus of the newly moved tooth undergoes minimal periodontal alterations. In addition, there can be a positive change in the width of the alveolar ridge,30Lindskog-Stokland B. Hansen K. Ekestubbe A. Wennström J.L. Orthodontic tooth movement into edentulous ridge areas—a case series.Eur J Orthod. 2013; 35: 277-285Crossref PubMed Scopus (27) Google Scholar as was observed in the present case. Moving teeth through the maxillary sinus is considered to be one of the most challenging treatment tasks in orthodontics, because it requires compensatory new bone apposition in the direction of tooth movement. Some papers reported root resorption, loss of pulp vitality, and perforation of the sinus membrane as possible complications after moving molars through a lowered maxillary sinus.31Wainwright W.M. Faciolingual tooth movement: its influence on the root and cortical plate.Am J Orthod. 1973; 64: 278-302Abstract Full Text PDF PubMed Scopus (144) Google Scholar, 32Daimaruya T. Takahashi I. Nagasaka H. Umemori M. Sugawara J. Mitani H. Effects of maxillary molar intrusion on the nasal floor and tooth root using the skeletal anchorage system in dogs.Angle Orthod. 2003; 73: 158-166PubMed Google Scholar However, it is well known that orthodontic tooth movement may also cause bone apposition at border structures, such as the sinus floor, as was demonstrated by Oh et al.33Oh H. Herchold K. Hannon S. Heetland K. Ashraf G. Nguyen V. et al.Orthodontic tooth movement through the maxillary sinus in an adult with multiple missing teeth.Am J Orthod Dentofacial Orthop. 2014; 146: 493-505Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar In a nonhuman animal experiment it was shown that the sinus wall may maintain a consistent thickness.34Kuroda S. Wazen R. Moffatt P. Tanaka E. Nanci A. Mechanical stress induces bone formation in the maxillary sinus in a short-term mouse model.Clin Oral Investig. 2013; 17: 131-137Crossref PubMed Scopus (13) Google Scholar The total treatment time was 12 months, which is relatively short compared with the reported average of 24–48 months for cases requiring molar mesialization.35Hom B.M. Turley P.K. The effects of space closure of the mandibular first molar area in adults.Am J Orthod. 1984; 85: 457-469Abstract Full Text PDF PubMed Scopus (61) Google Scholar Active mesialization of the second molar was commenced shortly after the reported loss of the maxillary first permanent molar. Most conventional straight-wire approaches involve a preliminary phase of alignment and leveling, which serve to delay the commencement of active space closure. The patient was particularly pleased about the lack of visibility of the appliance, maximizing the smile esthetics during treatment and reducing the risks of enamel decalcification and root resorption. There were no significant complications noted or reported during and after orthodontic treatment. The patient was highly motivated and maintained good oral hygiene. Bilateral maxillary orthodontic traction of the second and third upper molars into the missing maxillary first molar space was achieved without retracting or even using the anterior teeth, by means of an implant-supported mechanical procedure. The total treatment time of 12 months was well below reported averages in the literature for molar mesialization. The desired objectives of smile and facial esthetics, functional occlusion, and stability were achieved without complications.