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A mesially impacted mandibular second molar. Treatment considerations and outcome: A case report
A mesially i npacted mandibular second molar. Treatment considerations and outcome: A case report Esther Gazit, DMD, ~ and Myron Lleberman, DDS, MS b Tel Aviv, Israel
The uprighting of an impacted mandibular second molar presents special problems that may require auxiliary appliances and the implementation of "therapeutic diagnosis." In this case, the presence of an ectopically positioned third molar required modification of the original treatment plan. (AM J ORTHOO DENTOFACOFITHOP 1993;103:374-6.)
Mandibular second molar impactions, although less frequently encountered than third molar impactions, present challenging treatment procedures. The mandibular second molar impactions may result t~rom space gaining procedures in the mixed dentition,' or from a space between tim developing mesially inClined tooth bud and the anterior adjacent tooth, whi'ch is not contributory to normal development and eruption.-" This extra space can develop after extraction or mesial movement o f the adjacent tooth. If the mesially impacted tooth is the third molar with first and second molars present, extraction may be the treatment of choice. If, however, one molar is missing, treatment of the impacted molar is mandatory to ensure a two-molar arch integrity for the patient. Surgical repositioning o f mesially impacted molars is a common procedure, but with the disadvantages of risking tooth vitality a n d / o r root ankylosis and resorption. 3'4 Orthodontic eruptive guided mechanics is the treatment of choice. ' s 6 The procedure may become difficult if the tooth position is deep and horizontal, and other factors complicate the problem. The case presented is such an example. Case Report A 15-year-old boy was sccn for orthodontic consultation. Medical and dental histories wcre noncontributory. Previous dental treatment consisted of several amalgam restorations. Tooth alignment and articulation exhibited a Class I arrangement with slight spacing in the anterior canine and premolar regions. Three of the four second molars '.,.'ere fully cntptcd. the two on the left side articulating normally. On the right
From the Maurice and Gabriela Goldschlcgcr Scht~l of Dental Medicine. Tel A',iv University, Israel. 'Deparlment of Occlusion t'Dcpartment of Orthodontics. Cop)right 9 1993 by the American Asso
374
Fig. 1. Pretreatment panoramic radiograph. Note impacted mandibular right second molar, missing mandibular right third molar, and mandibular left second premolar; also ectopic position of maxillary right third molar.
side, the maxillary ovcrerupted second molar was in mesiolingual rotation, occluding with the opposite mucoperiosteal tissue ,.,,'here tile second molar should have been. The only deciduous teeth ',,,'ere the mandibular right and left second deciduous molars. Marked bruxing facets were visible on the mesiopalatal cuspal incline of the maxillary canines, distal cuspal incline of the mandibular canines, and at the incisor area. No frcmitus or tooth mobility was detectable. Thee marginal gingiva exhibited slight gingivitis. Radiographic examination rcvealcd a mesially impacted mandibular right second molar and a congenitally missing mandibular right third molar. Maxillary and mandibular third molar tooth buds on the left side `',,'ere normally positioned, but the maxillary right third molar bud `',,'as located at the apical root area of the ovcrcrupted second molar. The mandibular left second premolar `',.'as also congenitally missing (Fig. I). The initial treatment plan consisted of (1) extraction of the right maxillary third molar and reimplantation at the site of the left second deciduous molar; (2) intrusion of the maxillary right second molar followcd by uprighting the inapatted antagonist- after surgical exposure; and (3) final tooth alignment.
American Journal of Orthodontics and Dentofacial Orthopedics Volume 103. N o . 4
Gazit and Lieberman
375
A
, ~
~
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Fig. 3. Panoramic radiograph 5 weeks after surgical exposure.
Fig. 2. A, Placement and use of intermaxillary mechanics (vertical elastics) for initial eruption. B, Combined interarch and intraarch mechanics (0.016 x 0.022-inch Blue EIgiloy) for conlinued uprighting. The arch wire was designed to transmit a
posterior superior force vector. Fig. 4. Mandibular occlusal removal appliance to reduce tissue impingement and premature occlusalcontact between maxillary and mandibular right second molars. The treatment plan had to be modified since the parents rejected extraction and reimplantation of the maxillary third molar after consultation with the oral surgeon. Active treatment started with maxillary partial banding to intrude the ovcrerupted second molar. After surgical exposure of the impacted molar, an attachment was bonded to the exposed occlusal third of the distal surface and vertical elastics initiated (Fig. 2, A). Although this procedure did not favor maxillary intrusion mechanics, it was thought that rapid initial mandibular uprighting took precedence. Five weeks later, it was possible to bond an additional bracket to the buecal surface of the impacted tooth, and combined intraarch and interarch eruption mechanics was started (Figs. 2, B, and 3). Subsequently, the vertical elastics were discontinued, and eruption was guided solely by mandibular arch wire mechanics. The mandibular arch wire had a positive eruptive effect but created a new problem: the buccal vestibular mucosa was pinched with each closure bctv,'een the maxillary second molar and the mandibular appliance. Hypertrophy soon occurred associated with inflammatory edema and areas of ulceration. The situation deteriorated rapidly and antibiotic treatment was applied to control inflammation. The mandibular wire was then removed. At that stage, an occlusal appliance was fabricated coy-
i~
"'
~
#
o
.
.
.
.
.
.
.
.
.
.
Fig. 5. Condition of buccal mucosa during use of mandibular removable appliance. ering all mandibular teeth except the exposed second molar, to raise the occlusal vertical dimension and to avoid impingementjn closure (Fig. 4). Mandibular eruptive mechanics ,,,,'ere again instituted. Mucosal irritation and inflammation partially subsided (Fig. 5). Dependency on the occlusal appliance was
376
Gazit attd L i e b e r m a n
American Journal of Orthodontics and Denmfacial Orthopedics April 1993
Fig. 6. Panoramic radiograph at time of decision to extract maxillary right second molar.
Fig. 7. Final panoramic radiograph. Note final uprighting of mandibular right second molar and the clear path for eruption of the maxillary right third molar.
complete at this stage since without the appliance the only occlusal contact was betv,'een the two right second molars. Asneither mandibular molar uprighting nor maxillary molar del~ression was complete (Fig. 6), a decision was made to extract the maxillary right second molar and allow the third molar to erupt in its place. Immediately after extraction, the final upri~_hting was accomplished (Fig. 7), and the appliance discarded. The patient was instructed to return for observation every 3 months. At the last visit, a tendency for overeruption of the mandibular second molar was noticed. As the opposing maxillary third molar ',,,'as far from eruption, the patient `',,'as offered the choice of either an occlusal appliance (maxillary or mandibular) to prevent the eruptive process of the second molar, or an A-splint betv,'een the mandibular right first and second molars. The latter, chosen by the patient, will control the occlusal position of the mandibular right second molar until the antagonist third molar is fully erupted and functioning.
gress as expected, possibly because of the presence of the third molar bud in its apical area. 2. Surgical removal and reimplantation of this third molar, because of its high position, would have required, according to the oral surgeon, general anesthesia. This was rejected by the parents. 3. The continuing premature contact between the mandibular uprighting molar and the maxillary overerupted molar, in addition to the buccal tissue irritation, required the use of an occlusal removable appliance. Although initially alleviating these problems, long-term use of the appliance was creating dependency and selective depression o f mandibular teeth. Extraction of the offending overerupted second molar enabled final uprighting of the impacted tooth and the potential for normal eruption of the maxillary right third molar. If that molar would have been absent or in a normal position, uprighting could have continued in conjunction with depression of the maxillary second molar, according to the original plan.
DISCUSSION
There are several special problems associated with uprighting horizontally impacted mandibular molars: (1) The pull on the impacted tooth produces reciprocal eruptive or depressive forces depending on whether the anchor teeth are located in the same or opposing arch. To minimize that effect, the anchor teeth should be fortified by either using additional teeth, cross palatal arches, or removable appliances. (2) The surgical procedure should provide a dry field and sufficient tooth exposure, well located, to bond an attachment that will allow force application in a favorable direction. (3) The design of the eruptive spring should minimize tissue irritation and allow for easy cleaning of the area. (4) The uprighting should b e closely monitored, and the presence of occlusal interference should be constantly examined. The uprighting process elongates the tooth and may easily create a premature contact leading to trauma in closure and resistance to the direction of.the eruptive forces. In the case presented, the treatment plan was altered for the following reasons: 1. Intrusion of the overerupted molar did not pro-
We appreciate the editorial assistance of Ms. Rita Lazar. REFERENCES I. Proffit WR. Contemporary orthodontics. St. Louis: CV Mosby, 1986:410. 2. Orton ItS. Jones SP. Correction of mesially impacted lower second and third molars. J Clin Orthod 1987;21:176-81. 3. Peskin S, Graber TM. Surgical repositioning of teeth. J Am Dent Assoc 1970;80:1320-6. 4. Johnson JV, Quirk GD. Surgical repositioning of impacted second molar teeth. AM J ORTIIOD DENq-OFT,,CORTnOP 1987;91:242-51. 5. Fcrrazzini G. Uprighting of a deeply impacted mandibular second molar. A.',I J ORTIIOD DE~"rOF,,,COR'nlOP 1989;96:168-71. 6. Slodov !. Behrents RG, Dobrowski DP. Clinical experience with third molar orthodontics. AM J ORT|IOD DE.NTOF,XC ORTnOP 1989;96:453-61. Reprint requests to: Dr. Esther Gazit Department of Occlusion The Maurice and Gal~riela Goldschlegcr School of Dental Medicine Tel Aviv University Ramat Aviv 69978, Tel Aviv, Israel
The uprighting of an impacted mandibular second molar presents special problems that may require auxiliary appliances and the implementation of "therapeutic diagnosis." In this case, the presence of an ectopically positioned third molar required modification of the original treatment plan. (AM J ORTHOO DENTOFACOFITHOP 1993;103:374-6.)
Mandibular second molar impactions, although less frequently encountered than third molar impactions, present challenging treatment procedures. The mandibular second molar impactions may result t~rom space gaining procedures in the mixed dentition,' or from a space between tim developing mesially inClined tooth bud and the anterior adjacent tooth, whi'ch is not contributory to normal development and eruption.-" This extra space can develop after extraction or mesial movement o f the adjacent tooth. If the mesially impacted tooth is the third molar with first and second molars present, extraction may be the treatment of choice. If, however, one molar is missing, treatment of the impacted molar is mandatory to ensure a two-molar arch integrity for the patient. Surgical repositioning o f mesially impacted molars is a common procedure, but with the disadvantages of risking tooth vitality a n d / o r root ankylosis and resorption. 3'4 Orthodontic eruptive guided mechanics is the treatment of choice. ' s 6 The procedure may become difficult if the tooth position is deep and horizontal, and other factors complicate the problem. The case presented is such an example. Case Report A 15-year-old boy was sccn for orthodontic consultation. Medical and dental histories wcre noncontributory. Previous dental treatment consisted of several amalgam restorations. Tooth alignment and articulation exhibited a Class I arrangement with slight spacing in the anterior canine and premolar regions. Three of the four second molars '.,.'ere fully cntptcd. the two on the left side articulating normally. On the right
From the Maurice and Gabriela Goldschlcgcr Scht~l of Dental Medicine. Tel A',iv University, Israel. 'Deparlment of Occlusion t'Dcpartment of Orthodontics. Cop)right 9 1993 by the American Asso
374
Fig. 1. Pretreatment panoramic radiograph. Note impacted mandibular right second molar, missing mandibular right third molar, and mandibular left second premolar; also ectopic position of maxillary right third molar.
side, the maxillary ovcrerupted second molar was in mesiolingual rotation, occluding with the opposite mucoperiosteal tissue ,.,,'here tile second molar should have been. The only deciduous teeth ',,,'ere the mandibular right and left second deciduous molars. Marked bruxing facets were visible on the mesiopalatal cuspal incline of the maxillary canines, distal cuspal incline of the mandibular canines, and at the incisor area. No frcmitus or tooth mobility was detectable. Thee marginal gingiva exhibited slight gingivitis. Radiographic examination rcvealcd a mesially impacted mandibular right second molar and a congenitally missing mandibular right third molar. Maxillary and mandibular third molar tooth buds on the left side `',,'ere normally positioned, but the maxillary right third molar bud `',,'as located at the apical root area of the ovcrcrupted second molar. The mandibular left second premolar `',.'as also congenitally missing (Fig. I). The initial treatment plan consisted of (1) extraction of the right maxillary third molar and reimplantation at the site of the left second deciduous molar; (2) intrusion of the maxillary right second molar followcd by uprighting the inapatted antagonist- after surgical exposure; and (3) final tooth alignment.
American Journal of Orthodontics and Dentofacial Orthopedics Volume 103. N o . 4
Gazit and Lieberman
375
A
, ~
~
~
Fig. 3. Panoramic radiograph 5 weeks after surgical exposure.
Fig. 2. A, Placement and use of intermaxillary mechanics (vertical elastics) for initial eruption. B, Combined interarch and intraarch mechanics (0.016 x 0.022-inch Blue EIgiloy) for conlinued uprighting. The arch wire was designed to transmit a
posterior superior force vector. Fig. 4. Mandibular occlusal removal appliance to reduce tissue impingement and premature occlusalcontact between maxillary and mandibular right second molars. The treatment plan had to be modified since the parents rejected extraction and reimplantation of the maxillary third molar after consultation with the oral surgeon. Active treatment started with maxillary partial banding to intrude the ovcrerupted second molar. After surgical exposure of the impacted molar, an attachment was bonded to the exposed occlusal third of the distal surface and vertical elastics initiated (Fig. 2, A). Although this procedure did not favor maxillary intrusion mechanics, it was thought that rapid initial mandibular uprighting took precedence. Five weeks later, it was possible to bond an additional bracket to the buecal surface of the impacted tooth, and combined intraarch and interarch eruption mechanics was started (Figs. 2, B, and 3). Subsequently, the vertical elastics were discontinued, and eruption was guided solely by mandibular arch wire mechanics. The mandibular arch wire had a positive eruptive effect but created a new problem: the buccal vestibular mucosa was pinched with each closure bctv,'een the maxillary second molar and the mandibular appliance. Hypertrophy soon occurred associated with inflammatory edema and areas of ulceration. The situation deteriorated rapidly and antibiotic treatment was applied to control inflammation. The mandibular wire was then removed. At that stage, an occlusal appliance was fabricated coy-
i~
"'
~
#
o
.
.
.
.
.
.
.
.
.
.
Fig. 5. Condition of buccal mucosa during use of mandibular removable appliance. ering all mandibular teeth except the exposed second molar, to raise the occlusal vertical dimension and to avoid impingementjn closure (Fig. 4). Mandibular eruptive mechanics ,,,,'ere again instituted. Mucosal irritation and inflammation partially subsided (Fig. 5). Dependency on the occlusal appliance was
376
Gazit attd L i e b e r m a n
American Journal of Orthodontics and Denmfacial Orthopedics April 1993
Fig. 6. Panoramic radiograph at time of decision to extract maxillary right second molar.
Fig. 7. Final panoramic radiograph. Note final uprighting of mandibular right second molar and the clear path for eruption of the maxillary right third molar.
complete at this stage since without the appliance the only occlusal contact was betv,'een the two right second molars. Asneither mandibular molar uprighting nor maxillary molar del~ression was complete (Fig. 6), a decision was made to extract the maxillary right second molar and allow the third molar to erupt in its place. Immediately after extraction, the final upri~_hting was accomplished (Fig. 7), and the appliance discarded. The patient was instructed to return for observation every 3 months. At the last visit, a tendency for overeruption of the mandibular second molar was noticed. As the opposing maxillary third molar ',,,'as far from eruption, the patient `',,'as offered the choice of either an occlusal appliance (maxillary or mandibular) to prevent the eruptive process of the second molar, or an A-splint betv,'een the mandibular right first and second molars. The latter, chosen by the patient, will control the occlusal position of the mandibular right second molar until the antagonist third molar is fully erupted and functioning.
gress as expected, possibly because of the presence of the third molar bud in its apical area. 2. Surgical removal and reimplantation of this third molar, because of its high position, would have required, according to the oral surgeon, general anesthesia. This was rejected by the parents. 3. The continuing premature contact between the mandibular uprighting molar and the maxillary overerupted molar, in addition to the buccal tissue irritation, required the use of an occlusal removable appliance. Although initially alleviating these problems, long-term use of the appliance was creating dependency and selective depression o f mandibular teeth. Extraction of the offending overerupted second molar enabled final uprighting of the impacted tooth and the potential for normal eruption of the maxillary right third molar. If that molar would have been absent or in a normal position, uprighting could have continued in conjunction with depression of the maxillary second molar, according to the original plan.
DISCUSSION
There are several special problems associated with uprighting horizontally impacted mandibular molars: (1) The pull on the impacted tooth produces reciprocal eruptive or depressive forces depending on whether the anchor teeth are located in the same or opposing arch. To minimize that effect, the anchor teeth should be fortified by either using additional teeth, cross palatal arches, or removable appliances. (2) The surgical procedure should provide a dry field and sufficient tooth exposure, well located, to bond an attachment that will allow force application in a favorable direction. (3) The design of the eruptive spring should minimize tissue irritation and allow for easy cleaning of the area. (4) The uprighting should b e closely monitored, and the presence of occlusal interference should be constantly examined. The uprighting process elongates the tooth and may easily create a premature contact leading to trauma in closure and resistance to the direction of.the eruptive forces. In the case presented, the treatment plan was altered for the following reasons: 1. Intrusion of the overerupted molar did not pro-
We appreciate the editorial assistance of Ms. Rita Lazar. REFERENCES I. Proffit WR. Contemporary orthodontics. St. Louis: CV Mosby, 1986:410. 2. Orton ItS. Jones SP. Correction of mesially impacted lower second and third molars. J Clin Orthod 1987;21:176-81. 3. Peskin S, Graber TM. Surgical repositioning of teeth. J Am Dent Assoc 1970;80:1320-6. 4. Johnson JV, Quirk GD. Surgical repositioning of impacted second molar teeth. AM J ORTIIOD DENq-OFT,,CORTnOP 1987;91:242-51. 5. Fcrrazzini G. Uprighting of a deeply impacted mandibular second molar. A.',I J ORTIIOD DE~"rOF,,,COR'nlOP 1989;96:168-71. 6. Slodov !. Behrents RG, Dobrowski DP. Clinical experience with third molar orthodontics. AM J ORT|IOD DE.NTOF,XC ORTnOP 1989;96:453-61. Reprint requests to: Dr. Esther Gazit Department of Occlusion The Maurice and Gal~riela Goldschlegcr School of Dental Medicine Tel Aviv University Ramat Aviv 69978, Tel Aviv, Israel