Open Bite & Mesial Occlusion

Jaw Deformity Nomenclature: Category Aspect Names

• Size deformities can occur when the jaw is too large or too small.
• Hyperplasia refers to pathological enlargement.
• Hypoplasia signifies a failure to attain normal size.
• Micrognathia is synonymous with mandibular hypoplasia.
• Macrognathia corresponds to mandibular hyperplasia.
• Macrogenia indicates a large chin.
• Microgenia indicates a small chin.
• Abnormal jaw positions may occur in all cardinal directions.
• Prognathism and retrognathism are deformities with abnormal anteroposterior position.
• Anteroposterior position is assessed relative to the cranial base.
• Prognathism occurs when a jaw is positioned too far forward.
• Retrognathism happens when a jaw is positioned too far backward.
• In the transverse direction, the jaw can be displaced away from the median plane.
• Laterognathia is a deformity involving lateral displacement of the jaw.
• Vertical jaw deformities include excessive or insufficient downward displacement.
• Shape deformities involve completeness distortion, agenesis, clefts, or symmetry defects.

Geometric Classification of Jaw Deformities

• The human face exhibits reflection symmetry around the median plane.
• Facial symmetry requires two conditions: object symmetry and symmetric alignment.
• Object symmetry means each facial unit is symmetrical.
• Symmetric alignment means each unit is symmetrically aligned to the median plane.
• Jaws can have symmetry deformities due to object asymmetry or misalignment.
• Mandibular asymmetry and maxillary asymmetry refer to object symmetry abnormalities.
• Asymmetric alignment denotes abnormal alignment causing asymmetry.

Concepts of Completeness and Orientation

• Completeness refers to the wholeness of the jaw.
• A jaw can be incomplete due to the underdevelopment of its processes, such as agenesis of the condylar process of the mandible seen in hemifacial microsomia.
• Completeness can also be compromised by the failure of embryologic processes (e.g., clefts) or acquired defects.
• Malrotations occur when a jaw is abnormally oriented.
• Malrotations are classified according to the axis of abnormal rotation.
• Abnormal pitch occurs when the jaw is malrotated around the transverse facial axis.
• Abnormal roll, also known as cant, occurs when malrotation is around the anteroposterior axis.
• Abnormal yaw occurs when malrotation is around the vertical axis.
• Shape refers to the geometric characteristic of an object, excluding size, position, or orientation.
• A jaw with an abnormal shape is considered distorted.

Dental Arch and Occlusion Anomalies

• The teeth paradontium and alveolar ridge form the dental arch.
• The dental arch consists of extra-alveolar parts (crowns of teeth) and intra-alveolar parts (teeth roots).
• The dental arch is semi-circular in the deciduous bite, while in the permanent bite, the upper arch is elliptic, and the lower arch is parabolic.
• Anomalies can affect the entire dental arch and its frontal part.
• Dental arch anomalies are considered in three perpendicular planes: sagittal, transversal, and vertical.
• Sagittal anomalies include arch length discrepancies.
• Transversal anomalies involve narrowing or widening of the arch.
• Vertical anomalies include infra/supra anomalies.
• Dental arch elongation can result from upper respiratory pathologies characterized by open-mouth breathing, macrodentia, supernumerary teeth, swallowing problems, incorrect tongue articulation, and bad habits.
• Elongation frequently occurs with sagittal, transversal occlusion, and open disocclusion.
• Treatment during the deciduous bite includes risk factor elimination, massage, and myotherapy.
• Treatment using extra-oral appliances and prevention of arch growth are applied during the temporary bite.
• Fixed and removable intra-oral removable appliances and teeth extraction (if indicated) are used for the permanent bite.
• Shortening of the dental arch is caused by adentia, retention, incorrect location/eruption of tooth buds, early extraction of deciduous teeth, microdentia, abnormal jaw size, and bad habits.
• Shortening frequently occurs along with distal (mandibular dental arch) and mesial (maxillary dental arch) occlusion.
• Treatment in the deciduous bite period includes eliminating risk factors, normalizing functions, massage, and myotherapeutic exercises.

Dental Alignment and Molar Relationships

• Within a dental arch, deformity may affect the alignment, leveling, or spacing of teeth.
• Alignment refers to the arrangement of teeth in an arch.
• Ideal alignment involves the incisal edges of incisiors and buccal-cuspal ridges forming an arch involving canines, premolars, and molars.
• Misalignment can occur due to dental displacement, tipping, or rotations.
• Displacement is when a tooth is bodily moved outside the arch.
• Tipping is when a tooth is abnormally inclined.
• Rotations is when a tooth is misaligned due to abnormal rotation around its long axis.
• Leveling refers to the vertical arrangement of teeth.
• Abnormal leveling can affect single teeth or the entire arch.
• Assessment involves measuring the vertical position of teeth relative to their occlusal plane.
• The vertical positions of lower teeth are measured against the mandibular occlusal plane.
• The vertical positions of the upper teeth are measured against the maxillary occlusal plane.
• A tooth is in infraocclusion or supraocclusion when located below or above its ascribed occlusal plane.
• Dental leveling across the entire dental arch is gauged by the curve of Spee.
• The cusps, from the central incisor backward to the last molar, should inscribe a flat plane or a curved plane of slight upward concavity.
• The curve of Spee is deep when the cusps of the teeth trace a plane with a sharp upward curvature.
• The curve is reversed when the curvature of the plane has a downward concavity.
• Teeth should normally be spaced to touch without crowding in a dental arch.
• Spacing is abnormal when diastemas are present or when the arch cannot accommodate the teeth.
• Dental deformities can occur when upper and lower arches are not harmonized.
• Coordination of upper and lower dental arches is essential for normal occlusion which involves position, shape, and tooth size.
• Discordant dental arch positions cause malocclusion which can occur among anteroposterior, vertical, and transverse planes of the mouth.

Angle's Molar Relationship and Overjet

• Angle's molar relationship assesses the position of the buccal groove of the lower first molar relative to the mesiobuccal cusp of the upper molar.
• In an ideal Class I molar relationship, these landmarks coincide.
• In a Class II relationship, the lower molar groove is behind the upper cusp.
• In a Class III relationship, the lower molar groove is in front of the upper cusp.
• A similar assessment is done in the canine region.
• In a Class I canine relationship, the lower-canine-first-premolar embrasure coincides with the cusp of the upper canine.
• In a Class II canine relationship, the embrasure is behind the upper canine cusp.
• In a Class III canine relationship, the embrasure is in front of the upper canine cusp.
• Overjet is the horizontal distance between the incisal edges of the upper and lower central incisors.
• An ideal overjet is +2 mm which is when the lower incisal edge coincides with the upper, the overjet is zero.
• The overjet has a positive value if is behind, and a negative value if in front.
• Occlusion can be classified as neutrocclusion, distocclusion, or mesiocclusion.
• In neutrocclusion, molar and canine relationships are Class I, and overjet is normal.
• In distocclusion, molar and canine relationships are Class II, and overjet is greater than normal (Division 1) or normal (Division 2).
• In mesiocclusion, molar and canine relationships are Class III, and overjet is smaller than normal, usually negative.
• An open bite occurs due to the absence of vertical overlap between the upper and lower teeth and can be anterior or posterior.
• A deep bite is the result of excessive vertical-overlap of the anterior teeth.
• Posterior bite collapse is due to excessive vertical-overlap of the posterior teeth, occurring when many posterior teeth are missing, without opposing occlusion, or with complete crossbite.
• Posterior crossbite occurs when the buccal cusps of the maxillary posterior teeth are lateral to the buccal cusps of the mandibular teeth.
• Brodie bite occurs when all lower teeth are inside the upper teeth.
• Scissor bite occurs when the upper teeth are inside the lower teeth.
• Arch shape-discordance can occur causing abnormal occlusion of upper and lower arches due to different shapes, such as a "U" shaped lower arch not fitting a "V" shaped upper.

Dental Arch Anomalies: Vertical and Transversal Planes

• Vertical plane dental arch anomalies include extrusion and intrusion, measured in relation to the occlusion curve.
• Extrusion of the dental arch is frequently combined with open disocclusion, distal and mesial occlusion.
• In deciduous and temporary bites, remove risk factors, restore oral cavity functions, and provide timely caries treatment.
• For adentia, provide reasonable prostheses.
• In the transversal plane, abnormalities include imbalance between masticatory, mimic, and tongue muscles and impairment of swallowing, speech, and respiration.
• Other factors are bad habits (permanently open mouth, thumb sucking) and incorrect tongue location.
• Carious damages to teeth and their early extraction can create issues.
• Narrowing of the dental arch can be symmetric or asymmetric and occur on one or both jaws with or without occlusion problems.
• Treatments in the period of deciduous teeth include identifying and eliminating risk factors, myotherapy, and dental arch growth stimulation.
• If abnormality is present in the temporary bite removable appliancse can be used.
• Treatment is with fixed and removable appliances during the permanent stage.
• Widening is the rarest anomaly of the dental arch abnormalities often caused by incorrect location of the buds, delayed change of deciduous teeth, macrognathia, and tumors.
• Widening can be symmetric or asymmetric and can be combined with neutral, mesial, distal occlusions, or open disocclusion. treatments involves elimination of risk factors, suspension of jaw growth, massage, and myotherapy. variable bite, removable appliances are used. period of permanent bite permanent treatment.

Front Teeth Abnormalities and Treatment

• Front teeth abnormalities feature protrusion, retrusion, and crowding.
• Protrusion: characterized by vestibular inclination of the front teeth with the alveolar ridge, in most cases space is present between them.
• Causes: pathologies of respiratory airways, muscle dysfunction, and bad habits, frequently combined with distal occlusion.
• Deciduous and variable bite: treatment includes restriction of growth of the front part of alveolar ridge with an extra-oral appliance. of permanent bite-, correction with fixed and removable appliances
• Retrusion is characterized by oral inclination of the front teeth with the alveolar ridge.
• it: this abnormality is often combined with deep occlusion and distal occlusion.
• Crowding of the front teeth shows palatal or labial location of the teeth or their rotation.
• Crowding occurs in all types of abnormalities caused when there is disproportion between the sizes of the jaw and teeth, macrodentia, the inability to breath through the nose, early loss of deciduous molars
• Principles baseds on the degreee of denatl arch deformation an the patient's age. extraction,

Crossbite Malocclusion

• Crossbite is a transversal plane occlusion anomaly founds whith the teeth that are closest to the check, tongue or lip. lateral
• Occulsion that isn't at an central point, maxiliary teeth are on the bucall sides of the mandibular.
• Can be unilateral or bilateral. and skeletal, dental, or combined.
• Buccal cusps are located into the longitudinal fissures. (uni/bilateral) unilateral or bilateral palatino-occlusion.
• Palatal cusps touch the mandibular promolars or molars (uni/bilateral) and can be referred to as unilater/bilateral, maxilary westibule-occlusion.
• Shifts the mandible to one side while chewing, the result: cusp of cusp contac, unlateral fnctinal cross bite- the other being westibule-occlusion

Diagnostics and treatments of crossbite malocclusion

• At a time of the cross bite, the temporomandibular joint will have changes. side that is on Westiblue (palatine is closer to the palate. the mandiblar will turn inwards from the check
• Is related/ combindetion to desiral, medial etc.
• The goal: good contact!

Open Bite and Malocclusion

• This is an vertical plane, also its appearance is on the vertical gap on the teeth. It can show up in areas of anterior(Arteriors) or the buccal teeth
• If on contact, the teeth will make first point on the cuspidates, premolars, or molars
• A person with an open bite will experience disorder in speech, chewing and can affect breathin
• Types is dental-alveolar, skeletal and combined ( 3 times)
• excessive tooth devoplment.
• unde developed

Open bite continued

• A type of distoccusion, join and the articular cavity will widden

Etiology & Treatment of Open Bite

• Causes are genetics or diseases during birth
• Treatment: give up habit, tongue, finger, ect
• Dental-alveolar form -bad habits
• Skeletal caused by disorders
• This can develop as craniofacial

Diagnostics And Goals For open Bite

• Orthodontic treatment, give back faces esthetics

Deep Bite disocclusion

• A vertiacal plain, where teeth overlap one another
• Upper anteriror can can overlay 1/3 to 2/3
• Clinicaly is when the anomalies depend one one another
• Curves of sprree if to low it cn reach 2mm and a normal crwve is.9mm
• Forms there is, dentoalbeolar is deep bite, sketal for, and. combined

Deep Bite Etiology and Forms

• Albelar ridge, wear t and damage due to a bad habit.

Treatment

• To chew or not, to much raw product is not great due to the overgrowth of the normal
• Maintiaince and appliances

Mesial Bite

• According to angle is a sagital palne is class ll
• Lower front teeth mat ouch the upper teeth/ underbite
• Originaes from the greek
• types there are skeleton, dentao and combed
• Estic functions are to do with longiation

Mesial Occlusion and Treatment**

• functional orders: disorder of articulation, disorders of biting and chewing.

• Elioogy : genetics, birth teyoma e

• treatment of extraction ect

II bite anomaly class of distal occlusion

• In greek prgognatshm
• Bucle medial cup of macilacryl is molor is located anertiour o inter-sup
• Early sign: the location is of istal suffuces od second molars one verical line
• Most widespread among white (caucasin) the world
• Distal ocllsuion by itself
• treatment for this is extrahion e

Questions about open bite malocclusion, craniofacial structures, and mesial occlusion including skeletal and dentoalveolar factors. Assessment includes diagnosis using imaging techniques for comprehensive treatment planning. Also covers Angle's classification of malocclusion.