MODIFICATION OF CLASSI FICATION SYSTEMS FOR MAXILLARY IMPACTED TEETH
The classification systems for the maxillary impacted third molar are essentially the same as for the impacted mandibular third molar, However, several distinctionsand additions must be made to assess more accurately the difficulty of removal during the treatment-planningphase of the procedure. oncerning, angulation, the three types of maxillary third molars are (1) the vertical impaction (Fig. 9-39, A), (2) the distoangular impaction (Fig. 9-39, B), and (3) the mesioangular impaction (Fig. 9-39, C). The vertical impaction OCCUrsapproximately 63O,{) of the time, the distoangular approximately 25%, and the mesioangular position appr oximately ]2% of the time. Rarely other positions, such as a transverse, inverted, or horizontal position, are encountered; these. unusual positions account for less than 1’X, of impacted maxillary third molars., The same angulations in mandibular third molar extractions cause opposite degrees of difficulty for maxillary third molar extractions. Vertical and distoangular
impactions are the easiest to remove mesioangularimpactions are the most difficult (exactly the opposite of impacted mandibular third molars). Mesioangular impactions are more difficult to remove because the bone
that overlies t he impaction and that must be removed orexpanded is on the posterior aspect of the tooth and is much heavier than in the vertical or distoangular impaction. In addition, access to the mcsloangularly ositionedtooth is more difficult. The position of the maxillary third molar in a buccopalataldirection is also important for deter.ninu ,g the difficulty
of the removal. Most maxillary third molars areangled toward the buccal aspect of the alveolar process, which makes the “overlying bone in thai area thin and therefore easy to remove or to expand. Occasionally, the -impac ted maxillary third molar is positioned toward the palatal aspect of the alveolar process, This makes the too.th much more difficult to extract, because greater amounts of bone must be removed to gain access to the underlying tooth. A combination of radlographic assessment and clinical
digital palpation of the tuberosity area can determine if the maxillary third molar is in the buccopalatal position. If the tooth is positioned toward the buccal, a definite palpablebulge is found in the area; if the tooth is palatally
.positloned, a bony deficit is found in t hat region. Wheneither is determined by clinical examination, the surgeon must anticipate a longer, more difficult procedure. The Pel! and Gregory A, B, and C classification used to diagnose the depth of impaction in the mandible is also used in the maxilla (Fig. 9-40). Preoperative assessment of the remaining classifications is the same. The.factors that influence the difficulty of mandibular impacted third molar removal are the same for maxillary third molar removal. For example, the individual impacted tooth root
morph ology plays a substantial role in determining thedegree of extraction difficulty. The most common factor that causes difficulty with maxillary third molar removal is a thin, non fused root with erratic curvature (Fig. 9-41).The majority of m axillary third molars have fused roots that are conic. However, the surgeon should examine thepreoperative radiograph carefully to ensure that .this is the situation with each individual impaction. The surgeon should also check the periodontal ligament, because
the wider the ligament space the-less difficult the tooth isto remove,’ In addition, similar to mandibular third .molars, the periodontal ligament space tends to decrease as the patient increases in age, The follicle surrounding the crown of the impacted tooth also has an influence on th-e difficulty of the extraction. “Ifthe follicular space is broad, the tooth will
be easier to remove than if the follicular space is thin or nonexistent.
BORe density is also an important factor in maxillary impaction removal and is related closely to the age of the patient. The younger the patient, the less dense and more elastic-and therefore more expandable-is the h(lr.~·sur
rounding the impact ed third molar. As the pat« nt ages,the bone becomes denser and less elastic, and the tooth becomes more difficult to remove.palatal aspect of the alveolar process, This makes the tooth much more difficult to extract, because greater amounts of bone must be removed to gain access to the underlyingtooth. A combination of radlographic assessment and clinical digital palpation of the tuberosity area can determine if the maxillary third molar is in the buccopalatal position.If the tooth is positioned toward the buccal, a definite palpable
bulge is found in the area; if the tooth is palatally.positloned, a bony deficit is found in that region. When either is determined by clinical examination, the surgeon must anticipate a longer, more difficult procedure.The Pel! and Gregory A, B, and C classification used to diagnose the depth of impaction in the mandible is also used in the maxilla (Fig. 9-40). Preoperative assessment of the remaining classifications is the same. The.factors that
influence the d ifficulty of mandibular impacted third molar removal are the same for maxillary third molar removal. For example, the individual impacted tooth root morphology plays a substantial role in determining the
degree of extraction difficulty. The most common factor that causes difficulty with maxillary third molar removal is a thin, non fused root with curvature (Fig. 9-41). The majority of maxillary third molars have fused roots that are conic. However, the surgeon should examine thepreoperative radiograph carefully to ensure that .this is
the situation with each individual impaction. The surgeonshould also check the periodontal ligament, because the wider the ligament space the-less difficult the tooth isto remove,’ In addition, similar to mandibular third
.molars, the periodont al ligament space tends to decreaseas the patient increases in age, . The follicle surrounding the cron of the impacted
tooth also has an i fluence on th-e difficulty of the extraction. “Ifthe follicular space is broad, the tooth will be easier to remove than if the follicular space is thin or nonexistent. BORe density is also an important factor in maxillary impaction removal and is related closely to the age of the patient. The younger the patient, the less dense and more elastic-and therefore more expandable-is the h(lr.~·surrounding the impacted third molar. As the pat« nt ages, the bone becomes denser and less elastic, and the tooth becomes more difficult to remove.
