- Email: [email protected]
Mounted dental casts
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Readers' forum
trauma negatively affected periodontal tissues. They also stated, “Like most long-standing controversies, no one now believes that excessive occlusal force initiates periodontal disease, nor does any credible person believe that occlusal force is incapable of causing periodontal injury.”4 Oh, how I wish those leading the debate on the role of occlusion in orthodontics also could recognize the areas of agreement. In the quest to root out perceived “heresies,” we end up paralyzing any possibility of finding practical answers to everyday questions. J. Michael Hudson Decatur, Ill Am J Orthod Dentofacial Orthop 2012;141:528-9 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.03.009 REFERENCES 1. Martin D, Cocconi R. Orthodontic dental casts: the case for routine articulator mounting (Point/Counterpoint). Am J Orthod Dentofacial Orthop 2012;141:8-16. 2. Rinchuse DJ, Kandasamy S. Orthodontic dental casts: the case against routine articulator mounting (Point/Counterpoint). Am J Orthod Dentofacial Orthop 2012;141:8-16. 3. Harrel SK, Nunn ME, Hallmon WW. Is there an association between occlusion and periodontal destruction? Yes—occlusal forces can contribute to periodontal destruction. J Am Dent Assoc 2006;137: 1380:82, 84. 4. Deas DE, Mealey BL. Is there an association between occlusion and periodontal destruction? Only in limited circumstances does occlusal force contribute to periodontal disease progression. J Am Dent Assoc 2006;137:1381:83, 85.
Tone of January Point/Counterpoint
I
enjoy reading the Point/Counterpoint feature that you initiated a year ago. It’s an excellent addition to the Journal. As a general dentist and an orthodontistin-training, I find that these features offer helpful perspectives on topics commonly surrounded by fact, myth, and opinion that make them difficult to navigate. I appreciate your introduction to this feature, advising that “there are some controversial topics that could benefit from a timely, well-referenced discussion or debate, looking at both sides of the topic. This is the purpose of Point-Counterpoint.”1 It is indeed critical to get at the heart of what’s best for our patients, and an informed dialog is the way to do it. After reading January’s Point/Counterpoint on whether routine mounting of orthodontic casts is necessary, I sensed that the written spirit of each position (perhaps “argument” is the better term) was unbalanced. I
don’t claim a comprehensive understanding yet of either side of this debate, and so I currently enjoy my view from on the fence. But if the Point/Counterpoint features serve the purpose for which I suspect they’re intended—to examine both sides of a topic—I humbly suggest greater equity in terms of written length and tone of each case, so that the platforms are more balanced. The concept of Point/Counterpoint is excellent, but the structure sometimes leads to less than an ideal discourse. It seemed to me that Drs Martin and Cocconi2 (Point) were invited into the boxing ring without being told that they were in a fight-to-the-death match. I can’t help but suspecting that, if Drs Rinchuse and Kandasamy3 (Counterpoint) had led with the Point instead, the corresponding argument would have been similarly asymmetric. I’m sure this speaks more to the format than to the authors themselves and simply suggests that we need more refereeing in the ring. Since I know that’s what we strive for, our own publications should reflect collegiality. I believe the debate can be more cordial if the goal is to simply go “1 round in the ring” rather than seeking a knockout every time. Marc Yarascavitch Toronto, Ontario, Canada Am J Orthod Dentofacial Orthop 2012;141:529 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.02.006 REFERENCES 1. Kokich VG. Changing of the guard (editorial). Am J Orthod Dentofacial Orthop 2011;139:1. 2. Martin D, Cocconi R. Orthodontic dental casts: the case for routine articulator mounting. Am J Orthod Dentofacial Orthop 2012;141: 8-14. 3. Rinchuse DJ, Kandasamy S. Orthodontic dental casts: the case against routine articulator mounting. Am J Orthod Dentofacial Orthop 2012;141:9-16.
Mounted dental casts
E
vidence-based dentistry will probably never settle the use of articulators in orthodontics. I was not trained to mount models. One case convinced me to change: an innocent-looking, mild Class II malocclusion in an adult with a deep overbite. After the appliances were placed and the proprioception changed, the mandible repositioned into a borderline surgical case (surgery had not been discussed). I was able to finish the treatment without surgery, but it left a lasting impression on me. I began routinely mounting dental casts in the
American Journal of Orthodontics and Dentofacial Orthopedics
May 2012 Vol 141 Issue 5
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Readers' forum
early 1980s. A superb orthodontist who read this letter commented that he had several similar patients who did require orthognathic surgery. In deciding about mounted dental casts, ask yourself: can I develop an occlusion at any mandibular (condylar) position and expect the patient to successfully adapt or is there a particular position that I should use as a goal? I believe there is good evidence from the orthopedic literature to support the statement of Okeson1: “The criteria for optimal orthopedic stability in the masticatory system would be to have even and simultaneous contacts of all possible teeth, when the condyles are in their most superoanterior position, resting against the posterior slopes of the articular eminences, with the discs properly interposed.” If the orthodontist believes that mandibular position doesn't matter, would he or she not expect a prosthodontist to use an articulator if full-mouth reconstruction were performed? Drs Rinchuse and Kandasamy2 argued against the use of articulators in orthodontics based on a lack of evidence that they are effective in diagnosis or treatment of temporomandibular joint disorders. Even if occlusion has nothing to do with temporomandibular disorders, there are valid dental reasons to give our patients a good occlusion. During diagnosis and treatment planning, a mounting allows us to determine where the patient is at that time in relation to the final goal. I believe the real question is not whether an orthodontist should mount dental casts, but how we should take the bite registration to mount them. Overcoming a patient's neuromuscular system and capturing centric relation accurately is challenging. My experience has been that, even though a mounting might not be perfect, it still provides more information about the nature of the malocclusion than models trimmed to maximum intercuspation. Articulators have flaws, but they are the best tool we have for diagnosing and planning treatment for our patients to a specific mandibular position at the present. G. Frank Petrick Sugar Land, Tex Am J Orthod Dentofacial Orthop 2012;141:529-30 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.03.010 REFERENCES 1. Okeson J. Selecting the best joint position: why all the controversy? Proceedings of the Roth Williams International Society of Orthodontists Annual Conference; 2011 May 18-20; Chicago, Ill. 2. Rinchuse DJ, Kandasamy S. Orthodontic dental casts: the case against routine articulator mounting. Am J Orthod Dentofacial Orthop 2012;141:9-16.
May 2012 Vol 141 Issue 5
Bone anchored maxillary protraction he thought-provoking article by Nguyen et al1 in the December issue reported on an assessment of maxillary protraction with bone anchorage. Comprehensive methods to treat maxillary deficiency are available in the orthodontic literature, but we thank the authors for opening new doors and concepts in the field. We have the following questions regarding their study.
T
1.
2.
3.
4.
5.
6.
What about the force vector direction, since the maxillary plates were placed below the center of resistance of the maxilla? This will tend to rotate the maxilla downward in the posterior part and upward in the anterior part; this is not ideal in Class III patients. The mandibular plates were placed between the canines and the lateral incisors, again anterior to the center of resistance of the mandible, which will tend to rotate the mandible in a counterclockwise direction and is contraindicated in Class III patients. The authors selected I-type plates, although it is well proven in the 3-dimensional studies by Lee et al2 and Cha and Ngan3 that the Y-type of plate has a distinct advantage over the I-type. The maximum amount of traction force applied by the authors was 250 g per side, but, for any kind of orthopedic correction, especially protraction of the maxilla, the minimum amount of force should be 400 to 450 g per side.4-6 The authors did not have any panoramic radiographs to show the actual position of the plates in the maxilla and the mandible. Only the Wits appraisal was used for assessment of the correction. How did the authors determine that the maxilla was protracted or the mandible was retracted, because the traction force is coming from the mandible? The authors haven’t considered or discussed the possible effects of opening or loosening of the circummaxillary sutural system, which could facilitate the orthopedic effect.7-9 Ajay Mathur N. G. Toshniwal Om P. Kharbanda Arvind Thakur Loni and New Delhi, India
Am J Orthod Dentofacial Orthop 2012;141:530-1 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.03.003
American Journal of Orthodontics and Dentofacial Orthopedics
Readers' forum
trauma negatively affected periodontal tissues. They also stated, “Like most long-standing controversies, no one now believes that excessive occlusal force initiates periodontal disease, nor does any credible person believe that occlusal force is incapable of causing periodontal injury.”4 Oh, how I wish those leading the debate on the role of occlusion in orthodontics also could recognize the areas of agreement. In the quest to root out perceived “heresies,” we end up paralyzing any possibility of finding practical answers to everyday questions. J. Michael Hudson Decatur, Ill Am J Orthod Dentofacial Orthop 2012;141:528-9 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.03.009 REFERENCES 1. Martin D, Cocconi R. Orthodontic dental casts: the case for routine articulator mounting (Point/Counterpoint). Am J Orthod Dentofacial Orthop 2012;141:8-16. 2. Rinchuse DJ, Kandasamy S. Orthodontic dental casts: the case against routine articulator mounting (Point/Counterpoint). Am J Orthod Dentofacial Orthop 2012;141:8-16. 3. Harrel SK, Nunn ME, Hallmon WW. Is there an association between occlusion and periodontal destruction? Yes—occlusal forces can contribute to periodontal destruction. J Am Dent Assoc 2006;137: 1380:82, 84. 4. Deas DE, Mealey BL. Is there an association between occlusion and periodontal destruction? Only in limited circumstances does occlusal force contribute to periodontal disease progression. J Am Dent Assoc 2006;137:1381:83, 85.
Tone of January Point/Counterpoint
I
enjoy reading the Point/Counterpoint feature that you initiated a year ago. It’s an excellent addition to the Journal. As a general dentist and an orthodontistin-training, I find that these features offer helpful perspectives on topics commonly surrounded by fact, myth, and opinion that make them difficult to navigate. I appreciate your introduction to this feature, advising that “there are some controversial topics that could benefit from a timely, well-referenced discussion or debate, looking at both sides of the topic. This is the purpose of Point-Counterpoint.”1 It is indeed critical to get at the heart of what’s best for our patients, and an informed dialog is the way to do it. After reading January’s Point/Counterpoint on whether routine mounting of orthodontic casts is necessary, I sensed that the written spirit of each position (perhaps “argument” is the better term) was unbalanced. I
don’t claim a comprehensive understanding yet of either side of this debate, and so I currently enjoy my view from on the fence. But if the Point/Counterpoint features serve the purpose for which I suspect they’re intended—to examine both sides of a topic—I humbly suggest greater equity in terms of written length and tone of each case, so that the platforms are more balanced. The concept of Point/Counterpoint is excellent, but the structure sometimes leads to less than an ideal discourse. It seemed to me that Drs Martin and Cocconi2 (Point) were invited into the boxing ring without being told that they were in a fight-to-the-death match. I can’t help but suspecting that, if Drs Rinchuse and Kandasamy3 (Counterpoint) had led with the Point instead, the corresponding argument would have been similarly asymmetric. I’m sure this speaks more to the format than to the authors themselves and simply suggests that we need more refereeing in the ring. Since I know that’s what we strive for, our own publications should reflect collegiality. I believe the debate can be more cordial if the goal is to simply go “1 round in the ring” rather than seeking a knockout every time. Marc Yarascavitch Toronto, Ontario, Canada Am J Orthod Dentofacial Orthop 2012;141:529 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.02.006 REFERENCES 1. Kokich VG. Changing of the guard (editorial). Am J Orthod Dentofacial Orthop 2011;139:1. 2. Martin D, Cocconi R. Orthodontic dental casts: the case for routine articulator mounting. Am J Orthod Dentofacial Orthop 2012;141: 8-14. 3. Rinchuse DJ, Kandasamy S. Orthodontic dental casts: the case against routine articulator mounting. Am J Orthod Dentofacial Orthop 2012;141:9-16.
Mounted dental casts
E
vidence-based dentistry will probably never settle the use of articulators in orthodontics. I was not trained to mount models. One case convinced me to change: an innocent-looking, mild Class II malocclusion in an adult with a deep overbite. After the appliances were placed and the proprioception changed, the mandible repositioned into a borderline surgical case (surgery had not been discussed). I was able to finish the treatment without surgery, but it left a lasting impression on me. I began routinely mounting dental casts in the
American Journal of Orthodontics and Dentofacial Orthopedics
May 2012 Vol 141 Issue 5
530
Readers' forum
early 1980s. A superb orthodontist who read this letter commented that he had several similar patients who did require orthognathic surgery. In deciding about mounted dental casts, ask yourself: can I develop an occlusion at any mandibular (condylar) position and expect the patient to successfully adapt or is there a particular position that I should use as a goal? I believe there is good evidence from the orthopedic literature to support the statement of Okeson1: “The criteria for optimal orthopedic stability in the masticatory system would be to have even and simultaneous contacts of all possible teeth, when the condyles are in their most superoanterior position, resting against the posterior slopes of the articular eminences, with the discs properly interposed.” If the orthodontist believes that mandibular position doesn't matter, would he or she not expect a prosthodontist to use an articulator if full-mouth reconstruction were performed? Drs Rinchuse and Kandasamy2 argued against the use of articulators in orthodontics based on a lack of evidence that they are effective in diagnosis or treatment of temporomandibular joint disorders. Even if occlusion has nothing to do with temporomandibular disorders, there are valid dental reasons to give our patients a good occlusion. During diagnosis and treatment planning, a mounting allows us to determine where the patient is at that time in relation to the final goal. I believe the real question is not whether an orthodontist should mount dental casts, but how we should take the bite registration to mount them. Overcoming a patient's neuromuscular system and capturing centric relation accurately is challenging. My experience has been that, even though a mounting might not be perfect, it still provides more information about the nature of the malocclusion than models trimmed to maximum intercuspation. Articulators have flaws, but they are the best tool we have for diagnosing and planning treatment for our patients to a specific mandibular position at the present. G. Frank Petrick Sugar Land, Tex Am J Orthod Dentofacial Orthop 2012;141:529-30 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.03.010 REFERENCES 1. Okeson J. Selecting the best joint position: why all the controversy? Proceedings of the Roth Williams International Society of Orthodontists Annual Conference; 2011 May 18-20; Chicago, Ill. 2. Rinchuse DJ, Kandasamy S. Orthodontic dental casts: the case against routine articulator mounting. Am J Orthod Dentofacial Orthop 2012;141:9-16.
May 2012 Vol 141 Issue 5
Bone anchored maxillary protraction he thought-provoking article by Nguyen et al1 in the December issue reported on an assessment of maxillary protraction with bone anchorage. Comprehensive methods to treat maxillary deficiency are available in the orthodontic literature, but we thank the authors for opening new doors and concepts in the field. We have the following questions regarding their study.
T
1.
2.
3.
4.
5.
6.
What about the force vector direction, since the maxillary plates were placed below the center of resistance of the maxilla? This will tend to rotate the maxilla downward in the posterior part and upward in the anterior part; this is not ideal in Class III patients. The mandibular plates were placed between the canines and the lateral incisors, again anterior to the center of resistance of the mandible, which will tend to rotate the mandible in a counterclockwise direction and is contraindicated in Class III patients. The authors selected I-type plates, although it is well proven in the 3-dimensional studies by Lee et al2 and Cha and Ngan3 that the Y-type of plate has a distinct advantage over the I-type. The maximum amount of traction force applied by the authors was 250 g per side, but, for any kind of orthopedic correction, especially protraction of the maxilla, the minimum amount of force should be 400 to 450 g per side.4-6 The authors did not have any panoramic radiographs to show the actual position of the plates in the maxilla and the mandible. Only the Wits appraisal was used for assessment of the correction. How did the authors determine that the maxilla was protracted or the mandible was retracted, because the traction force is coming from the mandible? The authors haven’t considered or discussed the possible effects of opening or loosening of the circummaxillary sutural system, which could facilitate the orthopedic effect.7-9 Ajay Mathur N. G. Toshniwal Om P. Kharbanda Arvind Thakur Loni and New Delhi, India
Am J Orthod Dentofacial Orthop 2012;141:530-1 0889-5406/$36.00 Copyright Ó 2012 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2012.03.003
American Journal of Orthodontics and Dentofacial Orthopedics