Introduction
Malocclusion is associated with adverse psychological problems, negative social consequences, and compromised functions of the stomatognathic system, including longevity of dentition and oral health. Findings of a study on condition-specific impact about oral impacts on daily performances in different malocclusions have shown that malocclusion has physical, psychological, and social effects on quality of life (QoL).
A systematic review suggests that malocclusion and orthodontic treatment needs are associated with poor health-related quality of life (HRQoL) in the same population, although the association is modest. A direct association exists between malocclusion severity measured as orthodontic treatment needs and oral health-related quality of life (OHRQoL) scores. Females show a greater negative impact on their OHRQoL. School children with malocclusion are more likely to experience an adverse impact on OHRQoL than those without malocclusion. A systematic review has reported that adolescents with severe levels of malocclusion might have the worst ranks of OHRQoL. The detrimental effects of malocclusion on OHRQoL are swayed by the age of the adolescents as well as by their culture and environment.
Severe dental crowding and protrusion of maxillary dentition can lead to lower self-esteem compared to those with milder afflictions. According to research, dental aesthetics play a crucial role in one’s social life and could even affect one’s chances of finding a job. People with ideal smiles are perceived as more intelligent and are more likely to get hired than those with non-ideal smiles.
Adverse health-related consequences of malocclusion
Substantial direct effects of malocclusion are predisposition to dental diseases and loss of tooth substance. Malocclusion leading to an unaesthetic facial appearance may result in a low social image and psychological disturbances ( Figs 7.1–7.3 ). Compromised oral functions such as mastication, respiration, and speech can negatively impact a person’s QoL. Abnormal loss of tooth substance caused by traumatic deep bite will lead to reduced masticatory ability, compromised aesthetics, and pulpal diseases. Severe forms of posterior cross-bite and deep traumatic bite lead to reduced jaw function and masticatory ability, which can adversely affect the health and functions of the temporomandibular joint ( Figs 7.4 and 7.5 ).
Benefits of orthodontic treatment in a young girl with class II division 1 malocclusion.
This girl’s improved aesthetics and enhanced self-esteem following orthodontic treatment are evident in post treatment photographs. (A) Poor facial aesthetics in a 12-year-old girl, unable to close her lips due to malocclusion. She had significant proclination of maxillary incisors and a lower lip trap. Both of her maxillary central incisors and left lateral incisor were chipped. (B) She underwent comprehensive orthodontic treatment with functional appliance followed by full fixed appliance therapy. Aesthetic restoration of fractured tips of the incisor teeth resulted in enhanced aesthetics.
Mal-alignment of teeth lead to an increase in plaque accumulation.
Severe crowding in the maxillary and mandibular arches impacts plaque removal and could lead to gingival disease.
Erupted mesiodens resulting in poor aesthetics.
Facial asymmetry and malocclusion.
Impacted maxillary left canine in a patient with facial asymmetry. Her upper and lower incisors are crowded, along with buccal cross-bite on the left side. This case was diagnosed with maxillary hypoplasia, unilateral hyperplasia of the mandible right side and significant facial asymmetry, which are better appreciated on a 3-D cone beam computed tomography volumetric image.
Gross facial asymmetry in an adult caused by growing unilateral condylar hyperplasia of the left side.
Note a significant cant of the occlusal plane and adaptation of the maxillary dentition to maintain occlusal contacts with the opposite arch.
Indirect consequences of malocclusion are connected with increased susceptibility to periodontal disease and dental caries. A traumatic bite can lead to occlusal trauma, while crowded dentition is associated with a predisposition to dental caries.
In a spaced dentition, lack of tight proximal contacts between the teeth leads to the compromised function of spillways, reducing the natural cleansing action of food in removing the plaque and thereby leading to increased proneness to dental caries and periodontal disease ( Table 7.1 ).
TABLE 7.1
Consequences of malocclusion
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Adverse social consequences due to poor aesthetics
The face is the most exposed part of the human body, an organ of expression and communication. When the aesthetics are compromised, a patient may develop a negative body image and psychological disturbances, which could manifest as poor performance at school, poor interpersonal and workplace relationships, lost job opportunities, and poor matrimonial alliances. It is well known that severe deformity of the face and severe malocclusion can lead to a personality with introverted behaviour and psychological stress ( Fig. 7.6 ).
Malocclusion in a patient with hemifacial microsomia, associated with bilateral absence of ears and cleft of the palate.
Multiple specialists are required to treat and rehabilitate such a deformity. He has been provided with an implant-supported ear prosthesis.
Physical appearance plays a role in a child’s social esteem, which includes facial and dental appearance, although these tend not to be primary factors. Children with buck teeth may get bullied at school, which may have devastating and long-lasting psychological implications. Teasing related to dental appearance appears to be particularly hurtful.
Concern about existing deformities may vary among individuals, races and people with different socioeconomic backgrounds and diverse ages. The individual’s adjustment to his/her imperfections in dental alignment could be variable and independent of the visible malocclusion. There is no evidence that children with visible irregularities will generally be emotionally handicapped.
Mild to moderate malocclusion can negatively impact daily performance and cause psychological stress, especially interpersonal sensitivity and depression in young adults.
Alteration in functions of the stomatognathic system
The essential functions of the stomatognathic system that malocclusion can adversely affect are masticatory performance, deglutition, speech and respiration.
Masticatory performance
Masticatory performance is evaluated by the ability of a person to grind food and the chewing force he/she can exert. It is likely to be compromised when occlusion is less than optimum, more so in association with certain specific malocclusion traits.
The diminished number of occlusal contacts and quality of contacts lead to a reduced ability to pulverise food into smaller particle sizes in the same number of strokes/unit of time compared with someone with normal abilities. Subjects with malocclusion have been found to chew food of larger particle sizes than the normal occlusion group. English et al. found median particle sizes for the subjects with classes I, II and III malocclusions to be approximately 9%, 15% and 34% larger, respectively, compared with those with normal occlusion.
Malocclusion associated with frequent interference in normal masticatory movements shows altered activities of the muscles involved in mastication and poor coordination of muscle functions. Individuals with scissors bite or cross-bite of the buccal segment show a lack of coordination of muscular activities, especially on the affected side. Research studies have shown that dental malocclusions were associated with significantly lower skilfulness of masticatory jaw motion, measured by kinematic parameters.
Patients with anterior open bite have limitations in biting using their incisors and holding objects between their front teeth.
Articulation and quality of speech
Speech articulation can be adversely affected in severe open bite, skeletal class III malocclusion with negative overjet, and severely malpositioned teeth. ,
Articulation errors occur primarily in the sibilants (s, z and sh, ch, j, dz), characterised mainly by combined visual and auditory distortions. Errors on the stop consonants (p, b, m, t, d, n) occur less frequently and consist of isolated visual distortions. While most subjects with class II malocclusion, with or without open bite, could assume a variety of tongue and mandibular postures that allowed them to approximate a (s) or (z), these compensations in subjects with class III malocclusion do not occur. In these class III cases, the tongue remains distal to the mandibular incisors, causing scattering of the air stream. In a study conducted in Poland on class III patients with mandibular prognathism, almost all patients exhibited speech disorders and severe articulation defects.
Abnormal respiration, snoring and obstructive sleep apnoea (OSA) proneness to sleep-disordered breathing
Malocclusion associated with abnormal craniofacial morphology could partially contribute to obstructive sleep apnoea. A narrowing of the pharyngeal airway is thought to arise from a combination of abnormal anatomical features of the craniofacial structures and functional impairment of the upper airway muscles. Retroposition of the facial skeleton leads to reduced oropharyngeal dimensions, making a person prone to snoring and sleep-related disorders. Increased anterior facial heights, inferiorly placed hyoid bone and reduced pharyngeal airway space are significant features of OSA in adults.
Children with growth disturbances leading to a narrow maxilla, mid-face deficiency and a retrognathic/small mandible are at greater risk of developing snoring and OSA. In these patients, the tongue assumes a more posterior and inferior position to accommodate itself in a smaller oral cavity, which may further compromise the existing narrow airway. Children born with a retrognathic mandible, such as seen in the Pierre Robin sequence, require immediate attention in holding the tongue forward along with the mandible to facilitate breathing and prevent asphyxia. Cleft palate surgery and/or pharyngeal flap surgery have been implicated in contributing to OSA and snoring in children.
Orthodontists have traditionally constructed appliances to hold the mandible forward in facilitating nasal breathing. Patients with retrognathia due to temporomandibular joint (TMJ) ankylosis suffer from OSA and benefit significantly after mandibular lengthening procedures.
Loss of tooth substance and function
Traumatic deep bite is one of the causes of pain in the lower anterior teeth and in the anterior palate. Supraerupted mandibular incisors cause trauma on the anterior palate, while retroclined upper incisors impinge on the labial gingiva of the lower incisors.
The tooth-attrition can also result from single-tooth malposition, which hinders normal masticatory functions. Deep bite affects the anterior teeth, causing wear on the labial/incisal edges of mandibular incisors and the palatal surfaces of maxillary incisors. The extent of attrition may vary depending on the severity of the deep bite and the interference it causes during functional jaw movements ( Fig. 7.7 ).
Loss of tooth substance of the maxillary and mandibular incisors associated with a deep bite.
Loss of enamel further leads to the wearing away of dentine and can cause pain and sensitivity of the affected teeth, leading to pulp exposure and consequent complications of pulpitis, including periapical abscess formation.
Many adults report complaints of their front teeth getting worn out, unaware of their existing traumatic deep bite. The rate of tooth substance wear may vary significantly from individual to individual. In other situations, the attrition of tooth substance leads to periodontal and endodontic complications. Prosthetic rehabilitation in these patients is challenging due to insufficient interocclusal space required to house the prosthesis. A traumatic deep overbite may result in unprotected incisors, adversely affecting the life of the dentition. Teeth in cross-bite also end up in attrition due to functional hindrances.
Increased susceptibility to traumatic dental injuries (TDI)
TDI are common in children and young adolescents and are of public health concern. The severity and extent of TDI can range from minor chipping of incisors to avulsion and dentoalveolar fractures. The extent of the damage caused by TDI depends on the type of injury. According to studies, TDI is more common among boys than girls.
Children in primary dentition
Evidence suggests that children in the primary dentition stage are at risk of trauma when overjet is greater than or equal to 3 mm. In addition, children in primary dentition with overjet, anterior open bite and inadequate lip coverage are more prone to TDI. A recent systematic review suggests that males with increasing age (1–2 years/2–3 years/3–4 years) and those with inadequate lip coverage, increased overbite, or overjet are at higher risk of having TDI in the primary dentition.
Early mixed/secondary dentition
An overjet greater than or equal to 5 mm in the early secondary dentition puts that at risk of TDI. Several studies have linked proneness to TDI with increased overjet in children and adolescents. The proclined maxillary anterior teeth become more prone to traumatic injuries if the lip coverage is inadequate. A significant relationship was found between the severity of trauma to the protrusion of maxillary incisors and the amount of lip coverage.
According to reports, the highest proportion of children aged 6 to 13 who experienced fractured or traumatic injuries to their anterior teeth had class II division 1 malocclusion and inadequate upper-lip coverage.
In general, children with overjet of more than 3 mm with inadequate lip coverage are at a higher risk of sustaining a crown fracture of the incisors. There is a 13% increase in the risk of trauma for every millimetre of increase in overjet. An increase in overjet of more than 3 mm doubled the incidence of coronal fracture, while an overjet of more than 6 mm increased the incidence fourfold. Soriano et al. have suggested the critical trauma susceptibility value of overjet of 5 mm or greater. , Generally, boys with large overjet are more prone to TDI than girls.
Recent studies have reiterated these observations. Among adolescents, the teeth most affected by dental trauma are the maxillary central incisors. Boys are known to have a 2.03 times higher risk of crown fracture than girls. Children with an overjet greater than 3 mm are 1.78 times more likely to suffer dental injuries. Children with insufficient lip coverage are 2.18 times more likely to experience TDI than those with adequate lip coverage. ,
In short, overjet, lip incompetence, and short lip line are important predisposing factors to coronal fracture of the anterior teeth. An increase in the overjet mainly determined the severity of the fracture.
Can early orthodontics using a functional appliance help to reduce traumatic dental injuries?
The findings of a higher incidence of dental trauma in patients with increased overjet suggest that these patients are likely to benefit from early orthodontic interventions before 11 years. Early orthodontic treatment in growing children should be considered appropriate in the assessment of the increased risk of dental trauma or a child being teased because of their overjet.
Proneness to dental diseases
Periodontal disease
Periodontal health in subjects with malocclusion can be compromised due to occlusal trauma and restricted access to the removal of plaque and, therefore, inadequate maintenance of oral hygiene.
Occlusal trauma associated with developing cross-bite during early mixed dentition leads to mobility of affected mandibular incisor(s) and loss of gingival attachment.
Severe crowding is found to be associated with increased plaque accumulation and gingivitis. In a systematic review, Bollen et al. (2008) reported a correlation between malocclusion and periodontal disease. Subjects with severe malocclusion are likely to have more severe periodontal disease than those with normal occlusion. Periodontal health is also dependent on the oral health status of an individual. Malocclusion per se cannot be implicated as the sole aetiology of periodontal disease. However, malocclusion is associated with increased periodontal diseases and poor oral hygiene maintenance. Large overjet has been associated with greater susceptibility to poor oral hygiene and gingivitis resulting from a dry mouth ( Figs 7.8–7.10 ).
A severe deep bite causes trauma to the periodontium of the mandibular incisor teeth.
Occlusal trauma leads to poor peridontal health.
Occlusal trauma from a single tooth in cross-bite has caused the gingival recession of the right mandibular central incisor.
Occlusal trauma leads to poor peridontal health.
Beginning of gingival recession in the mandibular incisors caused by occlusal trauma resulting from malposed central incisors and twin mesiodens.
Dental caries
Malocclusion has been implicated and associated with dental caries due to disturbed alignment, more significant plaque formation and difficulties related to its complete removal ( Fig. 7.11 ). A systematic review reported that subjects with lower dental aesthetic index (DAI) scores of malocclusion had lower caries measured as DMFT index.
Crowding of teeth causes difficulties in effective plaque removal, making them susceptible to dental caries and periodontal diseases.
Note interproximal caries on the maxillary right central and lateral incisors associated with crowding in this 14-year-old girl.
Benefits of orthodontic treatment
The purpose of orthodontic treatment varies depending on the case, as do the expected benefits. The short- and long-term achievable objectives must be identified and discussed. Although the primary motivation for seeking orthodontic treatment remains improvement in facial appearance, the perceived benefits and measurable benefits are influenced by patients’ and parents’ perception of malocclusion, the motivational reasons of the patient for undergoing treatment, the severity of malocclusion, and the complexity of disfigurement and its impact on oral health ( Figs 7.1 B, 7.12 ).
