Best Practices for Bite Problems Explained

Comprehensive diagnostic evaluation forms the foundation for successful malocclusion treatment. A systematic approach integrating multiple diagnostic modalities—radiographs, casts, photographs, and clinical assessment—generates treatment plans that address skeletal, alveolar, and dental problems appropriately. Without rigorous diagnosis, treatment recommendations often prove inadequate or inappropriate to patient needs.

Core Diagnostic Records

Panoramic radiographs provide a comprehensive overview of tooth development, number, position, and alveolar bone levels. Identify missing teeth, supernumerary teeth, retained deciduous roots, and any pathology. Measure ramus height and gonial angle to assess vertical growth patterns. Compare bilateral structures for asymmetry.

Lateral cephalometric radiographs reveal anterior-posterior and vertical skeletal relationships. The cephalogram demonstrates maxillary position relative to the cranial base (SNA angle), mandibular position relative to the cranial base (SNB angle), and their relationship (ANB angle). Vertical dimensions including mandibular plane angle, anterior facial height ratios, and incisor inclinations become apparent.

Intraoral photographs with and without retraction show dentition from anterior and lateral perspectives. These images document crowding severity, rotations, diastemas, and bite relationships. They serve as powerful communication tools with patients and facilitate comparison across treatment phases.

Digital or traditional plaster casts allow three-dimensional assessment impossible with radiographs alone. Evaluate arch form, crowding/spacing quantity, contact point relationships, curve of Spee, and cusp positioning in the transverse dimension. Casts reveal problems radiographs cannot show—specifically, the buccolingual tooth position.

Jaw relationship records require centric relation definition. The patient closes slowly without guidance into their most retruded position, demonstrating actual skeletal jaw relationship rather than habitual closure. This position reveals discrepancies between centric relation and centric occlusion.

Temporomandibular joint evaluation screens for dysfunction. Palpate lateral poles for tenderness, assess opening range (normal 40-50 mm), evaluate smoothness and symmetry of opening/closing movement, and listen for joint sounds (clicking, popping, grinding). TMJ problems may influence treatment planning, as some biomechanics exacerbate existing dysfunction.

Cephalometric Analysis Framework

SNA angle (sella-nasion-point A) averages 82 degrees and indicates maxillary anterior-posterior position. Values above 85 degrees suggest maxillary protrusion; values below 78 degrees suggest maxillary retrusion.

SNB angle (sella-nasion-point B) averages 80 degrees and indicates mandibular anterior-posterior position. Values above 83 degrees suggest mandibular protrusion; values below 76 degrees suggest mandibular retrusion.

ANB angle (point A-nasion-point B) averages 2 degrees and indicates skeletal molar Class II/III status. ANB greater than 4 degrees indicates Class II; ANB less than 0 degrees indicates Class III. Values between 0-4 degrees indicate normal Class I skeletal relationship.

Wits appraisal provides an alternative to ANB that avoids errors from variable nasion position. Measure the horizontal distance from points A and B projected onto the occlusal plane. Wits appraisal more accurately reflects true anterior-posterior jaw discrepancy, particularly in vertical or prognathic growth patterns.

Mandibular plane angle measurement from sella-nasion to gonion assesses vertical growth pattern. Values above 35 degrees indicate high-angle or hyperdivergent patterns; values below 20 degrees indicate low-angle or hypodivergent patterns. Vertical growth pattern influences treatment mechanics and long-term stability.

Incisor inclinations measured from mandibular or maxillary planes show anterior tooth position relative to skeletal bases. Vertical growth patterns influence incisor position—high-angle patients show more upright incisors, while low-angle patients show proclined anterior teeth.

Model Analysis Components

Bolton ratio compares maxillary and mandibular anterior tooth widths. Anterior ratio should measure 80.4 ± 2.3 percent (sum of mandibular anterior tooth widths divided by sum of maxillary anterior widths). Ratios above 83 percent suggest a mandibular tooth size excess requiring space closure or incisor stripping in the mandible.

Space analysis quantifies crowding or spacing present. Sum individual mesiodistal tooth widths and compare to available space. Crowding exceeding 4-5 mm typically requires extraction therapy or expansion. Space deficiency less than 2-3 mm may resolve through slight axial inclination changes without extractions.

Arch form assessment evaluates whether dentition matches ideal arch geometry. Significant deviations from normal arch form suggest skeletal compression or expansion problems. Compare the patient's arch form to individualized arch form norms rather than applying standard configurations to all patients.

Curve of Spee measurement from incisal edges and buccal cusps to the lowest point in the anterior region quantifies anterior-posterior occlusal plane inclination. Normal curves measure 1-3 mm; excessive curves suggest vertical skeletal discrepancies or anterior tooth extrusion.

Treatment Timing Decisions

Early interceptive treatment (Phase I) initiated at ages 7-8 addresses specific problems benefiting from modification during active growth. Crossbite correction through rapid palatal expansion should occur before midpalatal suture fusion, typically before age 12. Early expansion prevents adaptation of the maxillary dental structure to skeletal narrowness.

Class III functional anterior crossbite benefits from early intervention using facemask or reverse pull headgear. Starting treatment at ages 8-10 leverages anterior growth potential to correct the discrepancy. Delaying Class III treatment requires greater correction through fixed appliances or orthognathic surgery in adults.

Crowding exceeding 5 mm often benefits from Phase I extraction of deciduous canines and first molars to gain space. This approach reduces the risk that permanent incisors erupt into severe crowding. However, research increasingly questions the value of interceptive extractions; many clinicians defer crowding treatment to Phase II.

Anterior open bite habit intervention should begin immediately when thumb sucking or tongue thrust is identified. Break the habit; the open bite typically corrects spontaneously with normal eruption and tongue positioning. Delayed habit elimination allows skeletal adaptation to the habit, making correction more difficult.

Severe anterior dental crowding may warrant early treatment if the patient is cooperative and the clinician determines Phase I intervention will improve overall outcomes. However, many clinicians observe that Phase I extraction of space-releasing teeth provides minimal long-term advantage over waiting for natural space relief during mixed dentition.

Two-Phase vs. One-Phase Treatment Debate

Two-phase treatment provides early intervention for specific problems (crossbite, anterior open bite, severe Class III) followed by comprehensive fixed appliance treatment in the permanent dentition. The approach addresses skeletal problems early, potentially reducing severity of permanent dentition crowding.

Disadvantages include extended total treatment time (Phase I plus phase II typically requires four to five years of active treatment), increased cost, psychological burden of prolonged treatment, and risk that Phase I corrections relapse before Phase II completion.

One-phase treatment defers comprehensive treatment until permanent dentition establishment, typically starting around age 12. This approach provides single comprehensive treatment period, potentially shorter overall duration, and eliminates Phase I relapse concerns. Many crowding problems resolve naturally during mixed-to-permanent dentition transition.

Current evidence increasingly supports one-phase treatment for most malocclusions. Studies demonstrate equivalent long-term outcomes compared to two-phase treatment for crowding and anterior open bite. Two-phase treatment benefits remain most evident for Class III and crossbite problems requiring growth-dependent correction.

Evidence for Early Treatment Efficacy

Randomized controlled trials examining early treatment outcomes have produced mixed results. The Cochrane Review on Phase I treatment concluded that evidence does not support routine early treatment for crowding. However, selective early treatment for specific problems—particularly crossbite and Class III—demonstrates clear benefits.

Advantages of early treatment for crossbite include simpler correction during growth when palatal expansion produces skeletal widening rather than purely dental expansion. Early Class III treatment with facemask leverages growth potential, reducing the mandibular advancement surgery that might otherwise be necessary in adulthood.

Disadvantages include extended treatment duration, compliance burden during childhood, and reduced evidence for most early interventions. Many clinicians now recommend selective early treatment: address crossbite and Class III early when growth-dependent correction is beneficial, but defer crowding treatment until permanent dentition unless crowding compromises anterior tooth eruption.

Treatment Planning Documentation

Record cephalometric angles, dental and skeletal measurements on standardized forms. Photograph the original malocclusion from multiple angles before treatment initiation. Maintain documented treatment objectives addressing specific identified problems.

Develop a prioritized treatment plan: primary objectives (functional necessity), secondary objectives (aesthetic improvement), and tertiary objectives (minor refinements). Communicate these objectives with the patient and obtain informed consent before treatment begins.

Reassess treatment progress periodically through new cephalometric radiographs (typically annually), clinical photography, and cast models. Document progress toward identified objectives, reassessing whether initial treatment plan remains appropriate or requires modification based on actual treatment response.

Systematic diagnostic evaluation distinguishes comprehensive, evidence-based treatment planning from routine application of standard protocols. When clinicians rigorously diagnose, analyze growth patterns, evaluate skeletal relationships, and match treatment timing to diagnostic findings, outcomes improve and patient satisfaction increases significantly.

References

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