|Year : 2021 | Volume
| Issue : 4 | Page : 167-185
The open bite checklist manifesto
Heba E Akl1, Amira A Aboalnaga1, Yehya A Mostafa2
1 Department of Orthodontics, Faculty of Dentistry, Cairo University, Cairo, Egypt
2 Department of Orthodontics, Faculty of Dentistry, Cairo University; Department of Orthodontics, Future University, Cairo, Egypt
|Date of Submission
|Date of Acceptance
|Date of Web Publication
Dr. Heba E Akl
54 El-Malek, El-Saleh Street, Manial-Roda, Cairo
Source of Support: None, Conflict of Interest: None
Background and Purpose: The vertical problems and specifically the anterior open bite (AOB) malocclusion represent a challenging situation whenever they are encountered by an orthodontist. The multiple intervening etiologies, the skeletal dysplasia involved, the functional and esthetic problems contribute to the difficulty of the situation. AOB is a descriptive term; underneath which lies a variety of antithesis status that depicts a similar overall appearance. An astute orthodontist should be able to look beyond the overall image to identify the etiological factor(s) that caused such malocclusion and consider the contributing components to apply the appropriate treatment modality. The aim of this paper is to study the interaction between the various components contributing to the AOB malocclusion.
Methods: A subclassification has been proposed based on how these components present together differently (whether skeletal or dental open bites). A checklist of 10 questions has been formulated. The answers to these 10 questions in sequence were used through a specifically constructed diagnostic tree that should guide the orthodontist toward an accurate diagnosis.
Results: The checklist and diagnostic tree were successfully applied on five patients, which is thought to facilitate their treatment planning.
Conclusions: The detailed classification was useful in giving an idea on the clinical and cephalometric features of each patient. The checklist and the diagnostic tree helped to identify the exact offending factors for the presenting malocclusion. Accordingly, the most appropriate treatment option would be provided.
Keywords: Dental open bite, diagnostic criteria, diagnostic tree, open bite checklist, open bite, skeletal open bite
|How to cite this article:
Akl HE, Aboalnaga AA, Mostafa YA. The open bite checklist manifesto. Int J Orthod Rehabil 2021;12:167-85
Anterior open bite (AOB) is one of the most complex malocclusions to treat., This complicated nature is related to its multifactorial etiology,,, and thus, the lack of treatment predictability., There are two main types of AOB, namely the skeletal and dental variants., Many reports aimed at classifying and differentiating AOB, as well as analyzing the various components that contribute to this malocclusion.,, However, there is a lack of consensus on the exact inter-action between such components and their contribution to the presenting malocclusion, which renders accurate diagnosis difficult and specific treatment objectives hard to set.
Therefore, the aim of the current article is to provide a deeper insight on the association of the different components of AOB malocclusion, as well as suggest a detailed checklist for precise diagnosis. In order to reach our aim, a schematic approach was created as follows: first describing the diagnostic criteria of the types and subtypes of the open bite malocclusion, second, providing an open bite checklist and third; providing a diagnostic tree.
The different types and subtypes of open bite will be described, followed by the explanation of the open bite checklist and diagnostic tree.
Diagnostic criteria of open bite (TYPES AND SUBTYPES)
AOB is classified into skeletal and dento-alveolar types. The skeletal open bite (SOB) involves the hyper-divergent facial pattern, characterized by increased mandibular plane (MP) angle, lower anterior facial height, and gonial angle.,, In addition, the extra-oral features include lip incompetence, increased profile convexity, and open mouth appearance due to the clockwise mandibular rotation.,, As for the dento-alveolar variant, the skeletal morphology and extra-oral features of the patient are normal; however, the anterior teeth are under-erupted.,, The differential diagnosis between these two variants is based on both clinical and cephalometric findings.,, Nevertheless, both can be further classified into subtypes based on the component(s) contributing to each malocclusion. [Figure 1] shows a diagrammatic representation of the types and subtypes of AOB. Understanding this can clearly guide the orthodontist to an optimal treatment plan for each particular patient. A summary of the key skeletal and dento-alveolar cephalometric variables contributing to AOB are shown in [Table 1].
|Figure 1: Diagrammatic representation of the types and subtypes of anterior open bite
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|Table 1: Summary of the key skeletal and dento-alveolar cephalometric variables contributing to the anterior open bite malocclusion
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Type I: Skeletal open bite
Skeletal open bite is characterized by skeletal dysplasia, with the classical signs described by Bjork. The general clinical and radiographic features common to SOB are summarized in [Table 2].
|Table 2: The general clinical and cephalometric variables of skeletal open bite and dental open bite
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There are three subtypes of the skeletal AOB:
Uncompensated (Classical) skeletal open bite
This type refers to the pure form of SOB, that neither has any form of dental component (under-eruption of the anterior teeth), nor dental compensation (over-eruption of the anterior dento-alveolar segment) to mask the skeletal discrepancy. It has the classical cephalometric and clinical extra-oral features summarized in [Table 2].,,,,, This type is characterized clinically by the normal incisal show at rest and on smiling, which confirms the lack of dental contribution to the open bite. However, the over-eruption of the posterior segments, whether only maxillary or combined maxillary and mandibular posterior segments is manifested., This type also reveals normal resting tongue posture and adaptive tongue thrust swallowing.
Compensated skeletal open bite
This type includes dental compensation of the anterior dento-alveolus to mask the underlying skeletal discrepancy; hence the term “compensated.” This compensation is in the form of over-eruption of the upper and/or lower anterior segments, which is reflected clinically as increased incisal show at rest and on smiling (gummy smile) and actual decrease of the apparent AOB. Radiographically, there is increased heights of anterior dento-alveolar segments (U1-PP, L1-MP). The gummy smile presents an additional problem in that type and contra-indicates anterior teeth extrusion during orthodontic treatment. As for functional examination, there is normal resting tongue posture and adaptive tongue thrust swallowing, which is similar to the uncompensated type. This type of open bite is frequently seen with “mouth breathing” habit, as the mouth opening for long periods of time allows over-eruption of both anterior and posterior teeth.
Skeletal open bite with greater dental contribution
This is quite a common type in occurrence. In addition to the skeletal features, dental components are manifested, in terms of under-eruption of upper and/or lower anterior teeth.,,, The smile characteristics and cephalometric dento-alveolar measurements depend on which arch is involved. In case there is under-eruption of upper incisors, the smile arc becomes more or less flattened, and there is decreased incisal show at rest and on smiling. The cephalometric measurements will reveal decreased upper anterior dento-alveolar height and proclined upper incisors. Functional examination will show an anterior resting position of the tongue and anterior tongue thrust swallowing behind the upper incisors. In case there is under-eruption of lower incisors, the smile arc may be consonant, with normal incisal show at rest and on smiling. There will be markedly reversed curve of Spee in the lower arch. Cephalometric measurements will reveal decreased lower anterior dento-alveolar height and proclined lower incisors. Functional examination will show an anterior resting position of the tongue and anterior tongue thrust swallowing behind the lower incisors. In case there is under-eruption of upper and lower incisors, there will be a combination of the previously mentioned factors. This means that this third subtype of SOB will include features of the dental subtype to which it is associated.
(A summary of the features of the different subtypes of SOB s are described in [Table 3]).
|Table 3: Subtypes, description, and diagnostic features of skeletal open bites
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Dento-alveolar open bite
In contrast to the skeletal variant, the dental open bite is characterized by normal skeletal morphology. The etiology is mainly habitual causing under-eruption of upper and/or lower anterior teeth. These habitual factors include both the resting and functional positions of the tongue. The clinical and radiographic features of dento-alveolar open bite (DOB) are summarized in [Table 2].
Dento-alveolar open bite due to under-eruption of upper incisors
In this type, the tongue is usually resting forwards, behind the upper incisors, causing their proclination and under-eruption. Therefore, static and functional examination of the tongue will reveal these findings. This is reflected on the smile of the patient, decreasing the incisal show at rest and on smiling and reversing the smile arc. There will be exaggerated curve of Spee in the upper arch. Cephalometric measurements will reveal decreased upper anterior dento-alveolar height and proclination of upper incisors. This type of open bite is also closely related to other habits, like thumb sucking in its earlier stages in growing individuals. The classic “fish mouth appearance” describes the area where the thumb may enter and/or the tongue may rest.
Dento-alveolar open bite due to under-eruption of lower incisors
In this type, the tongue is usually resting forwards, behind the lower incisors, causing their proclination and under-eruption. The functional examination will reveal such findings. A characteristic feature also is the reversed curve of Spee in the lower arch. There might be lower teeth spacing as a result of the tongue thrusting. In severe forms, there may be anterior cross bite from the forceful thrusting and are usually associated with macroglossia. On the other hand, the smile arc and incisal show are expected to be normal or nearly normal, as the upper incisors are not affected. Cephalometric findings will reflect the under-eruption and proclination of lower incisors.
Dento-alveolar open bite due to under-eruption of upper and lower incisors
This type is a combination of the previous two types, so has features of both. Extra-oral smiling features of the first type will be present, with decreased incisal show at rest and on smiling and reversed smile arc due to the component related to upper incisors. Exaggerated curve of Spee in the upper arch and its being reversed in the lower arch will be seen. The tongue will be resting forward in the open bite area or behind upper and lower incisors. Spacing of the arches may be seen, and the presence of a habit like thumb sucking is a frequent finding. Cephalometric findings will be combined features of the first two types as well, including under-eruption and proclination of upper and lower anterior dento-alveolar segments.
(A summary of the features of the different subtypes of dental open bites is described in [Table 4]).
|Table 4: Subtypes, description, and diagnostic features of dental open bites
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Open bite checklist
The checklist comprises 10 questions [Figure 2]a and [Figure 2]b. Walking the orthodontist through the questions will enable using diagnostic tree to reach the type and subtype of AOB. The orthodontist should prepare the aforementioned cephalometric readings and then proceed through the rest of the questions in a live session with the patient. A summary description of the procedures needed for each question is presented in [Table 5].
The diagnostic tree [Figure 3] uses the answers to the first 5 questions of the checklist to determine the type and subtype of the AOB. The answers to Q1 and Q2 will determine whether this case is SOB or DOB.
In case answers to Q1 and Q2 are yes, the case is a SOB. Then, answer to Q3 is the first indication to which subtype this case belongs. In case there is normal incisal show, consonant smile arc and posterior gumminess, then it is either an “uncompensated SOB” or “SOB with a dental component due to under-eruption of lower incisors.” Differentiation is made through answer to Q4. If the incisal show is increased, with variable smile arc and presence of posterior gumminess (i.e., anterior and posterior gumminess present,” then it is probably a “compensated skeletal open bite.” In case there is decreased incisal show, flat or reversed smile arc, then it is “skeletal open bite with a dental component, which is either under-eruption of upper incisor only, or a combination of under-eruption of upper and lower incisors.” In this latter case only, the arrow to the final diagnosis will cross to the right side of the tree to determine which of the two diagnoses is correct.
The confirmation of the previous findings is provided by the answer to Q4, which identifies which cephalometric dento-alveolar components that are affected and hence, which subtype is more possible. (The exception to this is the ”SOB with under-eruption of upper only or upper and lower anterior teeth, for which the differentiation and confirmation crosses to the right side of the tree, will be discussed later). If the upper and lower anterior dento-alveolar heights and inclinations are normal, with increased maxillary and/or mandibular dento-alveolar heights, then it is an “uncompensated SOB”. If there is under-eruption of lower anterior dento-alveolus, with lower incisor proclination together with the increased posterior dento-alveolar heights, then it is a “SOB with dental component due to under-eruption of lower incisors.” On the contrary, if there is over-eruption of upper and/or lower anterior dento-alveolar heights together with the posterior ones, then it is a “compensated SOB.”
If the answers to Q1 andQ2 is No, then it is a case of DOB. Then, the answer to Q3 regarding the incisal show and smile arc will start the differential diagnosis of the subtypes. If there is decreased incisal show and flat or reversed smile arc, then it is either a DOB due to either under-eruption of upper only or upper and lower incisors. If there is normal incisal show and smile arc, then it is probably a “DOB due to under-eruption of lower incisors.”
The confirmation is through the findings of Q4, where if there is only under-eruption and proclination of upper incisors, then it is a “DOB due to under-eruption of upper incisors.” While, if there is under-eruption and proclination of upper and lower incisors, then it is most probably a “DOB due to under-eruption of upper and lower incisors.” In case there is under-eruption and proclination of lower anterior teeth, then this confirms it is a “DOB due to under-eruption of lower incisors.”
Answers to Q5 and Q6 will report the functional and resting positions of the tongue to confirm previous diagnoses. If the tongue rests and thrusts behind upper incisors, then a component of under-eruption and proclination of upper incisors will be present. Similarly, if it rests and thrusts behind lower incisors, then a component of under-eruption and proclination of lower incisors will be present. If it rests and thrusts behind both, then there will be a component of both.
The type that lies in the middle of the tree is the SOB with greater dental contribution, whether this latter thing is under-eruption of only upper or upper and lower anterior teeth. Therefore, this needs more attention, as the arrow crosses from the left side of the tree, where the skeletal component has been identified to the right side, where the associated dental component is to be identified. After the arrow crosses to the right side, the sequence of arrows is followed just as the way with a pure dental open bite (red arrows), and then, the final outcome is combined with the fact that there is a skeletal component.
After reaching the final diagnosis of the tree, it will be combined with the answers of the rest of the questions, denoting not only on the type and subtype of AOB but also the severity, components, the contributing etiology of the presenting malocclusion, and the associated orthodontic problems. Moreover, the growth status of the patient will be identified, as this would greatly affect the appropriate treatment modality for that particular patient. For example; the final diagnostic statement can be “a growing female patient (10-year-old) with severe skeletal uncompensated AOB, extending from right to left premolars, with mild spacing of 2 mm in the lower arch.” Appendix 1 shows how the open bite checklist and diagnostic tree were applied to 5 patients, to reach their detailed diagnosis.
As we believe in the importance of individualized treatment planning, this work aims to specify the different components contributing to the AOB malocclusion. This will facilitate tackling those specific components, aiming to achieve the best outcomes, stability, and esthetics. It has been so long that the AOB represented a great dilemma in the orthodontic practice, even with the introduction of new treatment modalities and successful outcomes.,,, The complexity of the diagnosis, the multi-factorial etiology and the multiplicity of contributing components are possible reasons for this dilemma.,, Therefore, the aim of this paper is to introduce a systematic simplified approach for the accurate diagnosis of the AOB. The identification of the different types and subtypes is challenging, and sometimes overlap may occur. This is because we are dealing with human beings, who have all the different combinations to different extents. Nevertheless, this is an attempt to highlight the main features of the different types to aid in the diagnosis and treatment planning.
As mentioned thoroughly in the literature, the AOB has been generally classified into skeletal and dental types.,, Looking deeper into the components that contribute to the AOB, it was found that some dento-alveolar and skeletal measurements are inter-related and can-by themselves constitute separate subtypes, with a definite treatment objective. For example, the uncompensated SOB, which involves over-eruption of the maxillary and/or the mandibular posterior segments, with normal anterior dentoalveolar heights and normal incisal show and smile arc. This entails the need for posterior dentoalveolar segments intrusion, while avoiding any inadvertent anterior teeth extrusion.
On the other hand, the SOB with greater dental contribution involves both over-eruption of the maxillary and/or the mandibular posterior segments in addition to under-eruption of upper and/or lower anterior dento-alveolar segments. In such cases, the treatment of choice will be combined posterior intrusion and anterior extrusion of the affected segments. This example presents a detailed description of the minor components that will direct the treatment plan toward the exact problem.
As for the compensated SOB, it is worth mentioning that it is one of the most difficult patterns of AOB, because as the dental compensation takes place, it decreases the amount of obvious AOB; however, it contra-indicates any anterior teeth extrusion, or actually indicates their intrusion. These treatment objectives are more sophisticated than any other subtype and require complicated mechanics or sometimes surgical intervention.
The orthodontic profession has accumulated stupendous know-how. Using the checklist and diagnostic tree is a strategy to overcome failure and try to unwind some of the algorithm underlying the AOB malocclusion. It utilizes the available knowledge, experience, and at the same time makes up for our inevitable human inadequacies by providing a schematic approach to ensure the adequate analysis of the involved parameters. In other words, it is an attempt to do the right things right, i.e., target the specific defective component for a particular form of AOB. Accordingly, successful, stable, and esthetically pleasing results would be achieved.
Further to this, validation steps are in progress to generalize such forms on a greater number of patients and in different populations.
Ethics approval and consent to participate
The included patients signed an informed consent for treatment at the orthodontic department, Faculty of Dentistry, Cairo University. Only their pretreatment records are used in this article.
Consent for publication
The included patients signed an informed consent for treatment at the orthodontic department, Faculty of Dentistry, Cairo University. This consent includes using their data in research and publication.
Availability of data and materials
All data are available within the manuscript and in additional files submitted with it.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
Appendix 1: Examples of cases using the open bite checklist and diagnostic tree
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Lin LH, Huang GW, Chen CS. Etiology and treatment modalities of anterior open bite malocclusion. J Exp Clin Med 2013;5:1-4.
Greenlee GM, Huang GJ, Chen SS, Chen J, Koepsell T, Hujoel P. Stability of treatment for anterior open-bite malocclusion: A meta-analysis. Am J Orthod Dentofacial Orthop 2011;139:154-69.
Cangialosi TJ. Skeletal morphologic features of anterior open bite. Am J Orthod 1984;85:28-36.
Kucera J, Marek I, Tycova H, Baccetti T. Molar height and dentoalveolar compensation in adult subjects with skeletal open bite. Angle Orthod 2011;81:564-9.
Pakshir H, Fattahi H, Jahromi SS, Baghdadabadi NA. Predominant dental and skeletal components associated with open-bite malocclusion. J World Fed Orthod 2014;3:169-73.
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Arat ZM, Akcam MO, Esenlik E, Arat FE. Inconsistencies in the differential diagnosis of open bite. Angle Orthod 2008;78:415-20.
Akl HE, Abouelezz AM, El Sharaby FA, El-Beialy AR, El-Ghafour MA. Force magnitude as a variable in maxillary buccal segment intrusion in adult patients with skeletal open bite. Angle Orthod 2020;90:507-15.
Schendel SA, Eisenfeld J, Bell WH, Epker BN, Mishelevich DJ. The long face syndrome: Vertical maxillary excess. Am J Orthod 1976;70:398-408.
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Arriola-Guill n LE, Flores-Mir C. Molar heights and incisor inclinations in adults with Class II and Class III skeletal open-bite malocclusions. Am J Orthod Dentofacial Orthop 2014;145:325-32.
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]