Topic: Facial profile outcomes compared with established ‘norms’ in patients undergoing bimaxillary orthognathic treatment for Class III malocclusions – an extensive audit.

Introduction

Soft tissue analysis norm is the act of facial reconstruction to bring about pleasure and balance in human beings. It is carried out on people with facial disability. It involves restructuring a thick integument part on the chin area by aligning the chin area with the lower incisor part of the jaw. Soft tissue analysis in man has proven vital in the self-esteem of a person. The subject of one`s attractive face is a matter of perception with little to almost no study on the matter.

Various studies in the science of physical appearance have given rise to an exciting discovery about esteem connection with facial appearance. Studies have come up with various ways of determining the facial characteristics. The methods include; anthropometry, photogrammetry, and computer imaging, among others. Different angles have been used as a basis for the facial determination. Efforts in human science have been made to help restructure the faces of persons born with facial abnormalities. The procedure involves various methods of identification of the deformities and scientifically correcting them using surgery. The perception of facial perfection in humans is mostly dependent on ethnic background, gender culture, and personality. These seem to point out that the soft tissue analysis is only possible for people with low esteem. People who think highly of themselves do not have issues of facial reconstruction. Soft tissue analysis has helped many people get their faces reconstructed. Facial reconstruction to a person means improved self-esteem.  Various angles are used in the soft tissue analysis procedure, all to ascertain the facial defects.  Studies suggest that the face has an H-angle of 7-15 degrees determined by a person`s skeleton. The angle is determined by the Frankfort plane, and line lined formed when two parts are fused; the extreme point of the soft tissues and the dominant lip.

 Ideal facial profile

Golden proportion

Humankind’s interest in and study of the ideal facial profile can be traced back long in the past of human history (Naini and Gill, 2008a). One of the early studies is documented in the book ‘De Divina Proportione’ which was written by Luca Pacioli and illustrated by Leonardo da Vinci in the 15th century. Facial balance and harmony were illustrated in woodcuts, and the face of golden proportion was mathematically and geometrically described to be the most aesthetically pleasing to the eye (Vinci and Pedretti, 2001).

Facial Averageness

Facial averageness is defined as the degree to which a given face resembles the majority of faces within a given population (Komori et al., 2009). Average faces are more attractive and aesthetically more pleasing than less typical and distinctive ones. (Langlois and Roggman, 1990, Rhodes et al., 1999) This was supported by the study conducted by Rhodes and Tremewan in 1996, where 30 photographs of each male and females were caricatured by computer to different averageness of facial characters. The results showed that attractiveness increased when the facial traits were in closer proximity to the norm or average same-sex configuration(Rhodes and Tremewan, 1996). In Rhodes’s later study in 2001, both Chinese and Japanese participants perceived average faces as attractive when evaluating different composite photos of faces of the same race and sex (Rhodes et al., 2001). This proved that the perception of beauty is biologically based and has little variation across cultures. Therefore, by comparing facial features to the norm values, we can objectively assess facial attractiveness and define the ideal facial profile of the people from the same race.

The golden proportion in modern dentistry

With the availability of photographs and cephalometry in modern dentistry, patients’ profiles can be recorded, and the dentoskeletal and soft tissue facial profile can be subjectively analysed, in which the measurements were made and able to be compared with established norm values. It is interesting that in 1982, Ricketts reported the mere existence of “the Divine Proportion” in the cephalometric and exact ideal values(Ricketts, 1982). Such a relationship advocates the scientific assessment of beauty and facial profile, which has been a subjective perception in the past. Similar findings were later supported by Amoric, in which “the Divine Proportion” was found in many cephalometric measurements at different growth stages(Amoric, 1995). Due to the interracial dimorphism, specific norm values were established with different researches to provide a basis for a quantitative assessment for ideal facial form.

Methods to evaluate facial profile
Cephalometric analysis of the soft tissues

Since the introduction of cephalography by Broadbent (Broadbent, 1931), various cephalometric analyses were developed to evaluate dentoskeletal patterns through the identification of mainly hard tissue landmarks. (Downs, 1948, Steiner, 1953, Tweed, 1954, Ricketts, 1979a, Ricketts, 1979b, Ricketts, 1979c) However, the underlying dentoskeletal pattern may not directly reflect a patient’s profile (Subtelny, 1959) due to the effects of variation of soft tissue thickness, which might mask or exaggerate the underlying dentoskeletal pattern(Park and Burstone, 1986). Normalized skeletal or dental values do not necessarily yield the desired aesthetic outcome (Bergman, 1999). Therefore, soft tissue parameters are needed in cephalometric analysis to appraise the aesthetic profile.

Photogrammetric analysis of the soft tissue

On the other hand, Stoner began to develop soft tissue analyses based on photogrammetry (Stoner, 1955). Different studies analysed profiles through photographs (Stoner, 1955; Peck and Peck, 1970; Epker, 1992; Neger, 1959), which were taken with standardization of the photographic technique. Patients were positioned in the natural head position (NHP), which is a reproducible position of the head, and extracranial planes were used to exclude the anatomical variation of intracranial reference lines. Photogrammetry was found to have excellent repeatability, and it is a reliable tool when the clinical photos are taken appropriately (Gavan et al., 1952, Neger, 1959, Howells and Shaw, 1985, Ghoddousi et al., 2007). It is simple, more cost-effective and requires less equipment compared to cephalometry, while at the same time reflecting the real patients’ profile as perceived by people as laymen.

Soft tissue analysis

Different reference lines and angles have been developed to evaluate the soft tissue profile from cephalometric analysis based on Caucasian samples: The “Aesthetic plane, E plane” ( nasal tip- soft tissue pogonion), was proposed by Ricketts to describe the profile (Ricketts, 1957), while Steiner later described the balanced profile when the upper and lower lips were in contact of a line, the “S line,” which is a  tangent from soft tissue chin to a point which bisects the nose (Steiner, 1959). Merrifield then defined the “Z angle” between the profile line, which is a line tangent to the soft tissue pogonion (Pog’) and the most prominent lip, and the Frankfort plane to critically appraise the lower face relationship. An angle of 80 °± 5° is defined to be aesthetically pleasing in adults (Merrifield, 1966).

Burstone, who was aware of the soft tissue variations in thickness, length, and postural tone, carried out an integumental profile analysis in 1958. Three artists chose forty young Caucasian adults (16-36 years old) with aesthetically pleasing faces at the Herron Institute of Art in Indianapolis out of a hundred persons. Lateral photographs were taken and analysed with multiple angular and linear measurements (Burstone, 1958). Some of the angular measurements, for example, nasolabial angle, mentolabial angle, and total facial contour, are still used extensively for research and clinical purposes nowadays. Later, a soft tissue analysis was suggested by Legan and Burstone to complement their dentoskeletal analysis. This analysis aimed to include only the most relevant and significant soft tissue measurements for the patient who required surgical-orthodontic care. An angular measurement, Lower face–throat angle (Sn-Gn’-C), was added to relate the position of the chin to facial appearance (Legan and Burstone, 1980).

The importance of facial convexity was also mentioned by Holdaway (Holdaway, 1984). He emphasised the appraisal of facial harmony and soft tissue thickness. He defined the “Harmony line, H line”: a line tangent to both Pog’ and upper lip (Ls) as a reference plane to evaluate the subnasal position, as well as the upper and lower lips. The “H angle” was formed between the H line and the facial plane (N’- Pog’) were used to measures upper lip prominence or retrognathism of the soft tissue chin with a standard range of 7-15 degrees in Caucasian patients. The soft tissue facial angle was incorporated in the analysis to study the profile convexity concerning the Frankfort plane. These angular measurements give the advantage of eliminating the variation in magnification of radiographs. Studies have been done to compare these values among different populations. Asian (Chinese and Japanese) tended to have obtuse H angle due to the more protrusive upper lip (Lew et al., 1992; Alcalde et al., 2000). In contrast, Anatolian Turkish were found to have generally similar profiles and values that conformed to established Holdaway norms except with an increased soft tissue chin thickness and upper lip thickness(Basciftci et al., 2003).

Powell and Humphreys introduced the concept of the “aesthetic triangle,” which is formed by the nasofrontal angle, nasofacial angle, nasomental angle, and cervicomental angle. This analysis focused on the nasal morphology, which is related to aesthetic triangles to other portions of the face, e.g., forehead, lips, and chin, to evaluate the overall facial proportion (Powell and Humphreys, 1984).

A comprehensive cephalometric analysis was developed by Arnett and his colleagues in 1999, based on the 19 critical facial traits, which were previously proposed in 1993 (Arnett and Bergman, 1993). Forty-six Caucasians adults (20 males, 26 females) with a Class I occlusion and reasonable facial balance were recruited. Standardised cephalograms were taken with the patient’s head in a. natural head position (NHP), b. the mandible in centric relation position (CR), and c. a relaxed lip posture to demonstrate the soft tissues relative to the hard tissues without muscular compensation for dentoskeletal abnormalities. Subjects were chosen for inclusion only based on the balance of facial parts, while the quality of individual facial components, i.e., beautiful eyes were disregarded. The study emphasised the marking of the critical midface structures with metallic markers so they could be identified on cephalometric head films for midface diagnosis. “True Vertical Line (TVL)” was established with a line passing through subnasal and perpendicular to the patient’s NHP as a reference point during the sagittal profile analysis. Norm values were developed for Caucasian males and females, respectively. Patients would deem to have a harmonious face when the facial trait values lay within the cephalometric norms (Arnett et al., 1999).

Class III Malocclusion
Definition

Edward Angle first defined malocclusion Class III based on the molar relationship as the lower molar mesially positioned relative to the upper molar with no specifications in regards to the line of occlusion(Angle, 1899). British Standard Institute (BSI) later defined the malocclusion according to the incisal relationship. In essence, the lower incisor edge lies anterior to the cingulum plateau of the upper incisors, with reduced or reversed overjet (British Standards Institute, 1983).

Prevalence

The prevalence of class III malocclusion presents with a high degree of variability among and within populations ranged from 0%-26.7% according to the systemic review conducted by Hardy and his colleagues. There were consistent reports of higher prevalence rates among Asian populations, in which Chinese and Malaysian groups showed a relatively higher mean rate of over 15% as compared to other races(Hardy et al., 2012). For European populations, a range of prevalence rates of 2% to 6% was suggested in some studies (Burgersdijk et al., 1991; Willems et al., 2002).

Aetiology

The aetiology of Class III malocclusion is multifactorial as a result of the interaction between genetic and environmental factors (Proffit, 2013).

Genetic factors

Familial genetic inheritance plays a substantial role in skeletal craniofacial dimensions(Harris et al., 1973). A strong relation between inheritance and mandibular growth has been reported with typical familial aggregation of mandibular prognathism(Litton et al., 1970; Mossey, 1999). The most famous example to demonstrate such a familial aggregation is the Hapsburg dynasty. The familial recurrence of distinctive characteristics of prominent lower jaw over multiple generations in this European royalty was recorded in many portraits(Hodge, 1977). An extensive heredity study of 2,050 individuals from 55 families with prognathic mandibles suggested a significant gene that influences the expression of mandibular prognathism with signs of Mendelian inheritance and a multifactorial component (Cruz et al., 2008). The genetic aetiology can further explain the variability of prevalence rate of Class III malocclusion among different ethnic groups.

Environmental factors:

Environmental factors have been suggested as a contributory to the development of Class III malocclusion. The nasal airway obstruction due to enlarged tonsils, which are always associated with habitual protruding of the mandible and Cl III malocclusion (Gold, 1949). A study later related the enlarged tonsils with forwarding projection of the tongue, with consequent pushing of the lower labial segment. (Nunes and Di Francesco, 2010) Dentally, the premature loss of primary teeth would aggravate crowding resulting in an irregular eruption of permanent teeth, and such irregularity might create premature contact and jaw deflection upon closure. It has a significant effect in the incisor region that the interference would usually produce forward jaw displacement and subsequently influence on mandibular growth (Proffit, 2013).

Systemic problems, for example, the hormonal imbalances and disturbances: such as gigantism or pituitary adenomas, can result in the excessive continuous growth of mandible, hence, the mandibular prognathism(Pascoe et al., 1960). Patients presented with congenital craniofacial anomalies, e.g., cleft lip and cleft palate, are more likely to develop Class III malocclusion due to the formation of scar tissue after surgical repair. Pressure from scar tissue can significantly inhibit healthy maxillary growth(Bardach et al., 1979). Such a phenomenon can also associate with a history of severe facial trauma resulting in a hypoplasia maxilla.

Features of Class III malocclusion

Various combinations of dental and skeletal elements can be accounted for a Class III malocclusion(Ellis and McNamara, 1984). Pure dental class III malocclusion may not have any notable skeletal discrepancy. In contrast, skeletal class III malocclusion is presented with a wide variety of underlying skeletal pattern associated with a sagittal imbalance of maxilla and mandible(Sanborn, 1955).

Skeletal Class III malocclusion

Facial skeletal characteristics:

Several studies tried to identify the significant skeletal component; however, the results are inconsistent. Sanborn studied the differences between the facial skeletal patterns of skeletal Class III malocclusion and grouped various types according to the underlying skeletal manifestation and the amount of maxillary and mandibular prognathism. From the Sanborn class III sample, 45.2% of patients presented with prognathic mandible with the average size of the maxilla, while 33% of the sample had retrusive maxilla without mandibular prognathism. Only 9.5% of the participant had a combination of maxillary retrusion and mandibular protrusion. Jacobson and his colleagues suggested similar findings that mandibular protrusion with a normal maxilla (49%) accounted for the majority of his Class III sample(Jacobson et al., 1974). In contrast, Ellis and McNamara reported a dominant skeletal pattern of combined maxillary retrusion and mandibular protrusion, which accounted for 30% of their sample(Ellis and McNamara, 1984). The difference might be due to the variation in sample selection of studies, where the patients in Ellis and McNamara’s sample group were all severe Cl III skeletal and went for surgical treatment.

Several common traits were identified among Class III patients: including the prominence of the mandible, concave profile, obtuse gonial angle, and acute cranial base angle (Sanborn, 1955, Jacobson et al., 1974). In terms of vertical dimension, Guyer, Ellis, Behrents, and McNamara reported that 59% of class III malocclusions had reduced or neutral lower facial heights compared to 41% of patients had increased lower facial heights (Guyer et al., 1986). Paranasal hollowing/ flatness and increased sclera show above the lower eyelid are the common signs for patients with maxillary hypoplasia, (Naini and Gill, 2008b). In contrast, skeletal asymmetries, particularly in conjunction with mandibular prognathism, are common in class III malocclusions (Severt and Proffit, 1997).

Dental characteristics:

In skeletal class III patients, the most common dental combination was protrusive maxillary incisors, retrusive mandibular incisors (Ellis and McNamara, 1984). This is a presentation of dentoalveolar compensation for the sagittal skeletal discrepancy under the influence of altered soft tissue balance(Proffit, 2013). Patients usually present with an edge-to-edge or an anterior crossbite occlusion. Depending on the underlying skeletal pattern, crowding is more likely to be seen in the hypoplastic maxilla. At the same time, mandibular arches are more likely to have well-aligned dentition in a prognathic jaw. The transverse discrepancy is closely related to Class III malocclusion due to the jaw size disharmony and the relative forward position of the mandible. Clinically the manifestation can be presented as buccal crossbite and transverse dental compensation with higher buccal inclinations of the posterior maxillary teeth and lingual inclinations of the mandibular second molars (Ahn et al., 2017).

Treatment of skeletal Cl III malocclusion

Because of the individual variation and diversity of facial growth and the continued significant growth of mandible until late teens, accurate growth prediction is not feasible. Treatment of patients with skeletal Class III malocclusion remains a challenging task in orthodontics(Proffit, 2013). At young individuals with growing capacity, growth modification aims to improve the skeletal discrepancy to reduce future therapeutic needs, e.g., orthognathic surgery(Pangrazio-Kulbersh et al., 2007). In an adult, treatment options would be orthodontic camouflage or a combination of orthodontics and surgery, depending on the severity of jaw discrepancy(Rodríguez de Guzmán-Barrera et al., 2017).

The envelope of discrepancy (Proffit, 2013)

The envelope of discrepancy provides semiquantitative guidance and graphical illustration on the limits of orthodontic treatment in the context of producing normal occlusion.

With the origin of the x- and y-axes indicating the ideal position of the incisors, the envelops shows the ranges of tooth movement that are achievable with different approaches, namely orthodontic camouflage (the inner envelope), growth modification (the middle envelope) and surgical treatment (the outer envelope). The shapes of the envelops are not symmetric, which indicates different tooth movement potential for each direction among each treatment approach.

Orthodontic camouflage – the inner envelope

For non-growing patients with a mild to moderate skeletal Class III malocclusion, orthodontic camouflage can be beneficial with the help of class III elastics or extraction of mandibular teeth, e.g., first premolars or incisors. The choice of extraction would be depended on the severity of anterior crowding in the mandibular arch, the Bolton discrepancy, and the degrees of negative overjet and overbite(Ngan and Moon, 2015).

With the availability of temporary anchorage devices which can provide a nearly absolute anchor during retraction and protraction of the mandibular and maxillary dentition, the possibility of tooth movement ranges expanded. It might be able to correct previously borderline cases with fixed appliances. However, the biologic limitations should be respected to keep the dentition within the alveolar housing (Ngan and Moon, 2015).

Growth modification – the middle envelope

Timing for growth modification is particularly important. Intervention at an early stage, such as mixed dentition or prepubertal growth phase, has been recommended to obtain maximum skeletal effect (Proffit, 2013). Many orthopedic appliances have been explored. Their uses would depend on the underlying skeletal pattern and the age of the patient, with certain limitations.

Functional appliances have been suggested to improve Class III malocclusion. However, studies have been suggesting their effects are principally due to dentoalveolar changes: proclining upper incisors, retroclining the lowers incisors (Seehra et al., 2012; Kidner et al., 2003).

Chincup was first used in 1836 on patients with a prognathic mandible aiming to restrain mandibular growth(Ngan and Moon, 2015). However, pieces of evidence consistently show a minimal effect on restraining mandibular growth. Instead, the Class III skeletal profile is improved through redirection of mandibular growth vertically, hence a downward and backward rotation (Chatzoudi et al., 2014; Mousoulea et al., 2016). Long-term stability is also questionable with considerable catch-up growth once the chin cup appliance therapy is discontinued (Sugawara et al., 1990; Ngan and Moon, 2015; Zere et al., 2018).

Many orthodontists favor protraction facemask for children with minor-to-moderate skeletal problems with a retrognathic maxilla (Proffit, 2013). Moderate evidence had confirmed the short term positive improvements in both skeletal and dental changes from early treatment (Woon and Thiruvenkatachari, 2017). Encouragingly, the long term stability is supported by other studies with positive soft tissue effects maintained after 5-6 year post-treatment (Pavoni et al., 2019; Mandall et al., 2016). The orthognathic surgery rate was reduced from 66% in a control group to 36% in the treated group, and 68% of patients presented with a sustained positive overjet after six years (Mandall et al., 2016). However, studies also reported backward rotation of the mandible (Baccetti et al., 2000; Arman et al., 2006; Mandall et al., 2016), which limits its use in patients with increased vertical proportions.

An innovative approach of miniplate anchorage combined with continuous Class III elastics was proposed in 2010 as the orthopedic management of patients with a maxillary deficiency (De Clerck et al., 2010). The advantage of the force transmitting to jaws directly to reduce the dentoalveolar effects produces significant improvements of maxilla position, overjet, and molar relationship without remarkable changes in maxillary incisor inclination (De Clerck et al., 2010, Baccetti et al., 2011). However, there is insufficient data from present studies to conclude its short- and long-term effects (Rodríguez de Guzmán-Barrera et al., 2017; Meyns et al., 2018).

Surgical treatment – the outer envelope

Advances in orthodontic techniques, such as the use of orthodontic mini-implants and mini-plates, may have reduced the necessity of orthognathic surgical procedures (Keim et al., 2014). However, for patients with severe skeletal discrepancy where tooth movement range excess the limits of non-surgical treatment approaches, orthodontic treatment combined with orthognathic surgery remains the only option to achieve a stable occlusion and a pleasing aesthetic outcome (Ngan and Moon, 2015, Ghassemi et al., 2014).

Mandibular surgery (Proffit, 2013)

Surgery for mandibular prognathism first started early in the 20th century that consisted of a mandibular body ostectomy: removing a molar or premolar tooth and an accompanying block of bone. Sagittal split osteotomy, which is an intraoral approach of vertical osteotomy along the anterior border of the mandibular ramus, was introduced in 1957 and marked the beginning of the modern era of orthognathic surgery. After years of modifications, the surgical technique is now commonly used for mandibular surgery because of several advantages: a. Freedom of mandibular movement: mandible can be set back or advanced as desired with the tooth-bearing segment being rotated down anteriorly when additional anterior face height is needed. b. Compatibility with rigid intraoral fixation (RIF): patients’ post-operation comfort can be improved as immobilization of the jaws during healing is not required. c. Excellent bone-to-bone contact after the osteotomy: this can minimise complications during healing and enhance postsurgical stability.

Maxillary surgery (Proffit, 2013)

The development of maxillary surgery has begun since the 1960s. After decades of modifications, Le Fort I down fracture technique, which allows repositioning of the maxilla in all three planes of space, was developed. This surgical technique has been dominating contemporary maxillary surgery due to its excellent stability with maxillary upward and forward movements. Segmental osteotomies can also be incorporated to allow the widening of the posterior maxilla to correct the transverse discrepancy. However, the range of movement is limited by soft tissue tension from palatal mucosa, and the stability is inferior as opposed to other movements.

Bimaxillary surgery

The surgical technique of simultaneously repositioning both jaws was available by the 1980s (Proffit, 2013). Since then, treatment with mandibular setback alone decreased remarkably among patients with mandibular prognathism, instead, two- jaw surgeries are currently the most popular surgical technique for Class III malocclusion (Proffit et al., 2012, Lee et al., 2017). Such a dramatic swing in surgical preference is mainly due to three aspects: a. Aesthetic outcome -Simultaneous maxillary advancement can allow a smaller mandibular setback to produce a more natural facial appearance (Proffit et al., 2012), b. Airway- correction of discrepancy with mandibular setback surgery alone causes narrowing of the pharyngeal airway, which might be a predisposing factor in the development of obstructive sleep apnoea syndrome (Abdelrahman et al., 2011, Hasebe et al., 2011, Chen et al., 2007) c. Stability – the outcomes of isolated mandibular setback surgery were consistently shown to be less predictable and less stable when compared to two jaw surgery (Proffit et al., 2012; Lee et al., 2017; Cho, 2007).

Soft tissue changes with bimaxillary surgery

Several cephalometric ratios of soft to hard tissue movements were used to predict changes in the facial profile in hard and soft tissues instead of absolute measures to eliminates the effect of height differences between men and women(Mobarak et al., 2001). These ratios are based on the mean values of soft tissue responses and usually related to maxillary or mandibular surgery alone (Hershey and Smith, 1974; Dann et al., 1976). However, significant inaccuracy of prediction among bimaxillary osteotomy was seen when applying these ratios on bimaxillary surgery planning compared to the single jaw surgery (Pospisil, 1987). Therefore, applying these ratios when planning bimaxillary surgery should be with caution.

Researches were done to study the correlations of soft and hard tissues with considerations of different factors on bimaxillary surgery. Generally, facial convexity, nasolabial angle, and upper- and lower-lip protrusion were improved with bimaxillary surgery. (Chew, 2005) Soft tissue changes in patients who had undergone bimaxillary surgery show stronger correlations of movement between hard and soft tissue in the mandible than in the maxilla (Altug-Atac et al., 2008, Chew, 2005, Koh and Chew, 2004, Jensen et al., 1992, Lin and Kerr, 1998, Becker et al., 2014) In the mandible, a stronger correlation was seen in the horizontal direction as opposed to the vertical direction. (Chew, 2005)

Altug-Atac specifically looked at the volume of the lips. Significant reductions in the upper lip areas were reported. However, significant forward movement in both the maxillary base and the upper lip (Altug-Atac et al., 2008), the same upper lip thickness reduction was reported in different studies. (Jokić et al., 2013)  This is explained by the lip compression and thinning due to the anterior advancement of the maxilla. (RA Bays, 1997) A significant reduction in the distance from the upper lip to the aesthetic line was also suggested by Ghassemi et al. and Marsan et al. (Ghassemi et al., 2014, Marşan et al., 2009) For the lower lip, the significant reduction in the lower lip volume and the backward movement of the mandible during surgery was primarily accounted for the dramatic improvement in facial profiles of bimaxillary surgery patients.

Different patterns of soft tissue changes were also studied according to the change in anterior face height during surgery. Jakobson et al. found that the increase in the nasolabial angle is more significant when face height was increased during the surgery. In contrast, the mentolabial angle decreased more when the patient’s face height is reduced. The upper lip thickness decreased and the lower lip thickness increased, irrelevant to the change in face height. (Jakobsone et al., 2013)

The thickness of soft tissues before surgery also plays a vital role in affecting soft tissue response to hard tissue change in surgery. Correlation analysis indicates a strong negative correlation between the thickness of soft tissues before surgery and changes in soft tissue. Patients with thicker soft tissue before surgery will have a significant reduction in the thickness of the soft tissue, vice versa. (Jokić et al., 2013)

Reason for Treatment – From Patient Perspective

Aesthetic improvement has been reported to be one of the influential motivating factors for many patients who decide to undergo orthognathic surgery. (Garvill et al., 1992, Bell et al., 1985, Singh, 1999, Fabre et al., 2009, Stirling et al., 2007) Works of literature reported a strong effect of the facial convexity angle as an indication of surgical treatment. (de Almeida and Bittencourt, 2009, Fabre et al., 2009) These studies consistently show people have lower intolerance on concave profiles on female, which is a common facial trait of Class III malocclusion. Bell et al. also found that patients who decided to undergo surgery had a more significant skeletal anteroposterior discrepancy and facial disharmony. (Bell et al., 1985) Aesthetic considerations seem to play a weighty role when patients decide to receive treatment surgically, and this decision was highly associated with how patients, as a layperson, precepting facial forms, and profile attractiveness as compared to professional rating. (Bell et al., 1985, Vargo et al., 2003) They value peer reactions to their appearance, which directly or indirectly affect their self-consciousness. (Vargo et al., 2003) The demand for orthodontic treatment not merely due to aesthetic reasons but also a valid intuition of social response and valuation. (Kerosuo et al., 1995)

Psyco-social impacts due to malocclusion

The adolescents in Britain is self-conscious about the disadvantageous impacts on their quality of life by malocclusions. In contrast, they complained about the negative influences on daily performance by their smiling. (Bernabé et al., 2009) Participants of a 15- year study in Denmark also experienced the same problem. They recalled significant impacts on self-perceptions and societal reactions regarding their dental appearance at the time of adolescence. They all viewed the anterior region of the dentition is the most conspicuous trait that affects their dental appearance, disregarding their gender. Unfortunately, such adverse psyco-social influences by malocclusion exist in not only adolescence but also adulthood. (Helm et al., 1986, Zhang et al., 2006)

Adult patients who sought orthognathic treatment expressed concerns about their abnormal facial appearance, which affect their self-esteem, behaviour, and social interactions. They felt embarrassed when they were laughing and wanted to look ‘more normal.’ (Stirling et al., 2007) Shaw et al. had done extensive work in this area. He found considerable implications for one’s self-esteem based on the level of satisfaction with his facial appearance. (Shaw et al., 1980a) Socially, individuals’ first impression is affected negatively due to physically unattractive traits. (Shaw et al., 1980a) People are frequently stereotyped based on dental features: i.e., prominent lower front teeth can give a person an aggressive appearance. (Shaw et al., 1980b) Shaw and his colleague studied the effect of dentofacial appearance on social attractiveness among young adults. The results indicated that faces with regular incisal arrangement evoked most favourable ratings for most of the social characteristics (e.g., intelligence, popularity, sexual attractiveness, and friendliness). However, he also emphases that background facial attractiveness, which is often more influential, should not be overridden by the dental condition. (Shaw et al., 1985)

Facial profile outcome of orthognathic surgery

Studies have been done to assess the outcome of orthognathic surgery from patient and clinical perspectives. Views from the patients and their peers can give a subjective impression from the layman aspect. At the same time, professional judgment can be done quantitatively with soft tissue analysis comparing patient post-operative facial traits with established ‘norms.’

Patients’ and peers’ perception

Chewing function and facial aesthetics concerning the lower face are viewed as the most distinctive factors for patient satisfaction after orthognathic surgery. (Rustemeyer et al., 2010) In terms of aesthetic improvement, studies have been consistently suggested a positive treatment outcome with orthognathic surgery. All of the patients from Garvill’s sample were benefited and satisfied with the orthognathic surgical treatment due to the favorable effects on them as individuals and in social situations. (Garvill et al., 1992) Similar advantageous treatment outcomes regarding dental and facial appearance, self-perception, and social life have been reported. (Phillips et al., 1992, Cunningham et al., 1996) Jesani et al. researched evaluating the surgical outcome in particular to patients with class III malocclusion. The peer group graded pre and post-surgical records. Records of patients who had surgical treatment perform better in social competence, intellectual ability, psychological adjustment, and attractiveness. (Jesani et al., 2014) Another study also drew a similar conclusion on marked improvement on perceived personality traits after surgery in patients with Class II and Class III malocclusion. (Sinko et al., 2012) The reports on outstanding improvements in self-perception and social situations on patients’ daily life can indirectly reflect the positive changes in facial profile and aesthetic after the surgery.

Cephalometric measurement with established norms

Chew in 2007 evaluated the aesthetic outcome of his 30 patients with Chinese ethical background by comparing the facial profile with cephalometric norms established by Lew et al. Six soft-tissue variables were measured, namely facial convexity angle (G-Sn-Pg’), vertical height ratio (G-Sn/Sn-Me’), nasolabial angle (Cm-Sn-Ls), upper lip to B-line (Ls to Sn-Pg’), lower lip to H-line (Li to Ls-Pg’) and mentolabial sulcus (Si to Li-Pg’). Complete normalization of cephalometric soft-tissue variables was not achieved within most patients; significant differences compared to the aesthetic norms were measured in four out of the six measurements. In which profile was more concave than the norm, whereas the values for vertical height ratio, lower lip to H-line, and mentolabial sulcus were significantly higher than the norms. However, the author mentioned the limitation of the study; it was unable to analyse the male and female outcomes independently due to the unavailability of gender-specific normative data(Chew et al., 2007).

Statement of the Problem

According to Powel, soft tissue analysis is made up of nasofacial, nasomental, and mentocervical angles. With this making the basis of studies, ideas of facial appearance have been built. Research groups all agree that soft tissue parameters are essential in the study and subsequent analysis of the facial defects in human beings. Studies consequently lead to reconstructive surgeries of the face. Facial reconstructive surgery is vital for people with facial deformations done after careful evaluation of the possibilities. The nasal tip modifies the metorcervical angle. The cervicomental angle seeks to analyse tissues based on subcutaneous neck tissue. All the procedural research have failed to put into consideration the flaws they carry. The research seeks to address the weaknesses of the mentioned procedures and try to fuse the ways. Fewer mistakes will mean more accuracy in soft tissue analysis.

Review of the literature.

The nasolabial angle which measures anteroposterior part of the upper teeth. The treatment of surgery can alter this. The lower face proportion seeks to correct the norm value. Various studies have been carried out on soft tissue analysis determination. Scientists in the past have managed to come up with various concepts of measurement of the facial formations in humans. The concept of facial reconstruction has made it possible to measure and determine facial soft tissues.

This literature review includes articles that mentioned the methods used to analyze the lower third of the adult face based on photographic documentation of patients. It excluded those that exclusively discussed cephalometric analysis through radiography; discussions on Angle class III; analyses of patients with sleep apnea or malformations; articles related to dental extractions and orthodontic devices; evaluations through computed tomography; ethnic studies or studies in children; and descriptions of surgical technique.

Literature Review

ABDELRAHMAN, T. E., TAKAHASHI, K., TAMURA, K., NAKAO, K., HASSANEIN, K. M., ALSUITY, A., MAHER, H. & BESSHO, K. 2011. Impact of different surgery modalities to correct class III jaw deformities on the pharyngeal airway space. J Craniofac Surg, 22, 1598-601.

AHN, J., KIM, S.-J., LEE, J.-Y., CHUNG, C. J. & KIM, K.-H. 2017. Transverse dental compensation in relation to sagittal and transverse skeletal discrepancies in skeletal Class III patients. American Journal of Orthodontics and Dentofacial Orthopedics, 151, 148-156.

ALCALDE, R. E., JINNO, T., ORSINI, M. G., SASAKI, A., SUGIYAMA, R. M. & MATSUMURA, T. 2000. Soft tissue cephalometric norms in Japanese adults. Am J Orthod Dentofacial Orthop, 118, 84-9.

ALTUG-ATAC, A. T., BOLATOGLU, H. & MEMIKOGLU, U. T., 2008. Facial soft tissue profile following bimaxillary orthognathic surgery. Angle Orthod, 78, 50-7.

AMORIC, M., 1995. The golden number: applications to cranio-facial evaluation. The Functional orthodontist, 12, 18-21, 24-5.

ANGLE, E. H. 1899. Classification of malocclusion. Dental Cosmos, 41, 248-264. .

ARMAN, A., UFUK TOYGAR, T. & ABUHIJLEH, E. 2006. Evaluation of maxillary protraction and fixed appliance therapy in Class III patients. Eur J Orthod, 28, 383-92.

ARNETT, G. W. & BERGMAN, R. T. 1993. Facial keys to orthodontic diagnosis and treatment planning. Part I. American Journal of Orthodontics and Dentofacial Orthopedics, 103, 299-312.

ARNETT, G. W., JELIC, J. S., KIM, J., CUMMINGS, D. R., BERESS, A., WORLEY, C. M., JR., CHUNG, B. & BERGMAN, R. 1999. ORIGINAL ARTICLE: Soft tissue cephalometric analysis: Diagnosis and treatment planning of dentofacial deformity. American Journal of Orthodontics and Dentofacial Orthopedics, 116, 239-253.

BACCETTI, T., DE CLERCK, H. J., CEVIDANES, L. H. & FRANCHI, L. 2011. Morphometric analysis of treatment effects of bone-anchored maxillary protraction in growing Class III patients. Eur J Orthod, 33, 121-5.

BACCETTI, T., FRANCHI, L. & MCNAMARA, J. A., JR. 2000. Treatment and posttreatment craniofacial changes after rapid maxillary expansion and facemask therapy. Am J Orthod Dentofacial Orthop, 118, 404-13.

BARDACH, J., KLAUSNER, E. C. & EISBACH, K. J. 1979. The relationship between lip pressure and facial growth after cleft lip repair: an experimental study. Cleft Palate J, 16, 137-46.

BASCIFTCI, F. A., UYSAL, T. & BUYUKERKMEN, A. 2003. Determination of Holdaway soft tissue norms in Anatolian Turkish adults. American Journal of Orthodontics and Dentofacial Orthopedics, 123, 395-400.

BECKER, O. E., AVELAR, R. L., DOLZAN, A. D. N., HAAS, O. L., JR., SCOLARI, N. & OLIVEIRA, R. B. D. 2014. Soft and hard tissue changes in skeletal Class III patients treated with double-jaw orthognathic surgery-maxillary advancement and mandibular setback. International Journal of oral and maxillofacial surgery, 43, 204-12.

BELL, R., KIYAK, H. A., JOONDEPH, D. R., MCNEILL, R. W. & WALLEN, T. R. 1985. Perceptions of facial profile and their influence on the decision to undergo orthognathic surgery. American journal of orthodontics, 88, 323-32.

BERGMAN, R. T. 1999. Cephalometric soft tissue facial analysis. American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics, 116, 373-89.

BERNABÉ, E., SHEIHAM, A. & DE OLIVEIRA, C. M. 2009. Impacts on daily performances attributed to malocclusions by British adolescents. J Oral Rehabil, 36, 26-31.

BRITISH STANDARDS INSTITUTE, B. 1983. Glossary of Dental Terms (BS 4492). London. British Standards Institute.

BROADBENT, B. H. 1931. A NEW X-RAY TECHNIQUE and ITS APPLICATION TO ORTHODONTIA. The Angle Orthodontist, 1, 45-66.

BURGERSDIJK, R., TRUIN, G. J., FRANKENMOLEN, F., KALSBEEK, H., VAN’T HOF, M. & MULDER, J. 1991. Malocclusion and orthodontic treatment need of 15-74-year-old Dutch adults. Community Dent Oral Epidemiol, 19, 64-7.

BURSTONE, C. J. 1958. The integumental profile. American Journal of Orthodontics, 44, 1-25.

CHATZOUDI, M. I., IOANNIDOU-MARATHIOTOU, I. & PAPADOPOULOS, M. A. 2014. Clinical effectiveness of chin cup treatment for the management of Class III malocclusion in pre-pubertal patients: a systematic review and meta-analysis. Progress in orthodontics, 15, 62-62.

CHEN, F., TERADA, K., HUA, Y. & SAITO, I. 2007. Effects of bimaxillary surgery and mandibular setback surgery on pharyngeal airway measurements in patients with Class III skeletal deformities. Am J Orthod Dentofacial Orthop, 131, 372-7.

CHEW, M. T. 2005. Soft and hard tissue changes after bimaxillary surgery in Chinese Class III patients. Angle Orthod, 75, 959-63.

CHEW, M. T., SANDHAM, A., SOH, J. & WONG, H. B. 2007. Outcome of orthognathic surgery in Chinese patients. A subjective and objective evaluation. The Angle orthodontist, 77, 845-50.

CHO, H. J. 2007. Long-term stability of surgical mandibular setback. Angle Orthod, 77, 851-6.

CRUZ, R. M., KRIEGER, H., FERREIRA, R., MAH, J., HARTSFIELD JR, J. & OLIVEIRA, S. 2008. Major gene and multifactorial inheritance of mandibular prognathism. American Journal of Medical Genetics Part A, 146A, 71-77.

CUNNINGHAM, S. J., HUNT, N. P. & FEINMANN, C. 1996. Perceptions of outcome following orthognathic surgery. Br J Oral Maxillofac Surg, 34, 210-3.

DANN, J. J., 3RD, FONSECA, R. J. & BELL, W. H. 1976. Soft tissue changes associated with total maxillary advancement: a preliminary study. J Oral Surg, 34, 19-23.

DE ALMEIDA, M. D. & BITTENCOURT, M. A. V. 2009. Anteroposterior position of mandible and perceived need for orthognathic surgery. Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons, 67, 73-82.

DE CLERCK, H., CEVIDANES, L. & BACCETTI, T. 2010. Dentofacial effects of bone-anchored maxillary protraction: a controlled study of consecutively treated Class III patients. Am J Orthod Dentofacial Orthop, 138, 577-81.

DOWNS, W. B. 1948. Variations in facial relationships: Their significance in treatment and prognosis. American Journal of Orthodontics, 34, 812-840.

ELLIS, E., 3RD & MCNAMARA, J. A., JR. 1984. Components of adult Class III malocclusion. J Oral Maxillofac Surg, 42, 295-305.

EPKER 1992. Adjunctive aesthetic surgery in the orthognathic surgery patient. In: McNamara J A, Carlson D S, Ferrara A (eds) Aesthetics and the treatment of facial form. Monograph No 28, Craniofacial Growth Series, Center for Human Growth and Development, University of Michigan, Ann Arbor, pp. 187–216.

FABRE, M., MOSSAZ, C., CHRISTOU, P. & KILIARIDIS, S. 2009. Orthodontists’ and laypersons’ aesthetic assessment of Class III subjects referred for orthognathic surgery. European journal of orthodontics, 31, 443-8.

GARVILL, J., GARVILL, H., KAHNBERG, K. E. & LUNDGREN, S. 1992. Psychological factors in orthognathic surgery. J Craniomaxillofac Surg, 20, 28-33.

GAVAN, J. A., WASHBURN, S. L. & LEWIS, P. H. 1952. Photography: An anthropometric tool. American Journal of Physical Anthropology, 10, 331-354.

GHASSEMI, M., JAMILIAN, A., BECKER, J. R., MODABBER, A., FRITZ, U. & GHASSEMI, A. 2014. Soft-tissue changes associated with different surgical procedures for treating class III patients. J Orofac Orthop, 75, 299-307.

GHODDOUSI, H., EDLER, R., HAERS, P., WERTHEIM, D. & GREENHILL, D. 2007. Comparison of three methods of facial measurement. Int J Oral Maxillofac Surg, 36, 250-8.

GOLD, J. K. 1949. A new approach to the treatment of mandibular prognathism. Am J Orthod, 35, 893-912, illust.

GUYER, E. C., ELLIS, E. E., 3RD, MCNAMARA, J. A., JR. & BEHRENTS, R. G. 1986. Components of class III malocclusion in juveniles and adolescents. The Angle orthodontist, 56, 7-30.

HARDY, D. K., CUBAS, Y. P. & ORELLANA, M. F. 2012. Prevalence of angle class III malocclusion: A systematic review and meta-analysis. Open Journal of Epidemiology, 2, 75-82.

HARRIS, J. E., KOWALSKI, C. J. & WATNICK, S. S. 1973. Genetic factors in the shape of the craniofacial complex. Angle Orthod, 43, 107-11.

HASEBE, D., KOBAYASHI, T., HASEGAWA, M., IWAMOTO, T., KATO, K., IZUMI, N., TAKATA, Y. & SAITO, C. 2011. Changes in oropharyngeal airway and respiratory function during sleep after orthognathic surgery in patients with mandibular prognathism. Int J Oral Maxillofac Surg, 40, 584-92.

HELM, S., PETERSEN, P. E., KREIBORG, S. & SOLOW, B. 1986. Effect of separate malocclusion traits on concern for dental appearance. Community Dent Oral Epidemiol, 14, 217-20.

HERSHEY, H. G. & SMITH, L. H. 1974. Soft-tissue profile change associated with surgical correction of the prognathic mandible. Am J Orthod, 65, 483-502.

HODGE, G. P. 1977. A medical history of the Spanish Habsburgs. As traced in portraits. Jama, 238, 1169-74.

HOLDAWAY, R. A. 1984. A soft-tissue cephalometric analysis and its use in orthodontic treatment planning. Part II. Am J Orthod, 85, 279-93.

HOWELLS, D. J. & SHAW, W. C. 1985. The validity and reliability of ratings of dental and facial attractiveness for epidemiologic use. American Journal of Orthodontics, 88, 402-408.

JACOBSON, A., EVANS, W. G., PRESTON, C. B. & SADOWSKY, P. L. 1974. Mandibular prognathism. American journal of orthodontics, 66, 140-171.

JAKOBSONE, G., STENVIK, A. & ESPELAND, L. 2013. Soft tissue response after Class III bimaxillary surgery. Angle Orthod, 83, 533-9.

JENSEN, A. C., SINCLAIR, P. M. & WOLFORD, L. M. 1992. Soft tissue changes associated with double jaw surgery. Am J Orthod Dentofacial Orthop, 101, 266-75.

JESANI, A., DIBIASE, A. T., COBOURNE, M. T. & NEWTON, T. 2014. Perceived changes by peer group of social impact associated with combined orthodontic-surgical correction of class III malocclusion. Journal of dentistry, 42, 1135-42.

JOKIĆ, D., JOKIĆ, D., UGLEŠIĆ, V., MACAN, D. & KNEŽEVIĆ, P. 2013. Soft tissue changes after mandibular setback and bimaxillary surgery in Class III patients. Angle Orthod, 83, 817-23.

KEIM, R. G., GOTTLIEB, E. L., VOGELS, D. S., 3RD & VOGELS, P. B. 2014. 2014 JCO study of orthodontic diagnosis and treatment procedures, Part 1: results and trends. J Clin Orthod, 48, 607-30.

KEROSUO, H., HAUSEN, H., LAINE, T. & SHAW, W. C. 1995. The influence of incisal malocclusion on the social attractiveness of young adults in Finland. Eur J Orthod, 17, 505-12.

KIDNER, G., DIBIASE, A. & DIBIASE, D. 2003. Class III Twin Blocks: a case series. J Orthod, 30, 197-201.

KOH, C. H. & CHEW, M. T. 2004. Predictability of soft tissue profile changes following bimaxillary surgery in skeletal class III Chinese patients. J Oral Maxillofac Surg, 62, 1505-9.

KOMORI, M., KAWAMURA, S. & ISHIHARA, S. 2009. Averageness or symmetry: Which is more important for facial attractiveness? Acta Psychologica, 131, 136-142.

LANGLOIS, J. H. & ROGGMAN, L. A. 1990. Attractive faces are only average. Psychological Science, 1, 115-121.

LEE, C. H., PARK, H. H., SEO, B. M. & LEE, S. J. 2017. Modern trends in Class III orthognathic treatment: A time series analysis. Angle Orthod, 87, 269-278.

LEGAN, H. L. & BURSTONE, C. J. 1980. Soft tissue cephalometric analysis for orthognathic surgery. J Oral Surg, 38, 744-51.

LEW, K. K., HO, K. K., KENG, S. B. & HO, K. H. 1992. Soft-tissue cephalometric norms in Chinese adults with esthetic facial profiles. J Oral Maxillofac Surg, 50, 1184-9; discussion 1189-90.

LIN, S. S. & KERR, W. J. 1998. Soft and hard tissue changes in Class III patients treated by bimaxillary surgery. Eur J Orthod, 20, 25-33.

LITTON, S. F., ACKERMANN, L. V., ISAACSON, R. J. & SHAPIRO, B. L. 1970. A genetic study of Class 3 malocclusion. Am J Orthod, 58, 565-77.

MANDALL, N., COUSLEY, R., DIBIASE, A., DYER, F., LITTLEWOOD, S., MATTICK, R., NUTE, S. J., DOHERTY, B., STIVAROS, N., MCDOWALL, R., SHARGILL, I. & WORTHINGTON, H. V. 2016. Early class III protraction facemask treatment reduces the need for orthognathic surgery: a multi-center, two-arm parallel randomized, controlled trial. J Orthod, 43, 164-75.

MARŞAN, G., CURA, N. & EMEKLI, U. 2009. Soft and hard tissue changes after bimaxillary surgery in Turkish female Class III patients. J Craniomaxillofac Surg, 37, 8-17.

MERRIFIELD, L. L. 1966. The profile line as an aid in critically evaluating facial esthetics. American Journal of Orthodontics and Dentofacial Orthopedics, 52, 804-822.

MEYNS, J., BRASIL, D. M., MAZZI-CHAVES, J. F., POLITIS, C. & JACOBS, R. 2018. The clinical outcome of skeletal anchorage in interceptive treatment (in growing patients) for class III malocclusion. International Journal of Oral and Maxillofacial Surgery, 47, 1003-1010.

MOBARAK, K. A., ESPELAND, L., KROGSTAD, O. & LYBERG, T. 2001. Soft tissue profile changes following mandibular advancement surgery: predictability and long-term outcome. Am J Orthod Dentofacial Orthop, 119, 353-67.

MOSSEY, P. A. 1999. The heritability of malocclusion: part 2. The influence of genetics in malocclusion. Br J Orthod, 26, 195-203.

MOUSOULEA, S., TSOLAKIS, I., FERDIANAKIS, E. & TSOLAKIS, A. I. 2016. The Effect of Chin-cup Therapy in Class III Malocclusion: A Systematic Review. The open dentistry journal, 10, 664-679.

NAINI, F. & GILL, D. 2008a. Facial Aesthetics: 1. Concepts and Canons. Dental update, 35, 102-4, 106.

NAINI, F. B. & GILL, D. S. 2008b. Facial aesthetics: 2. Clinical assessment. Dental update, 35, 159-70.

NEGER, M. 1959. A quantitative method for the evaluation of the soft-tissue facial profile. American Journal of Orthodontics and Dentofacial Orthopedics, 45, 738-751.

NGAN, P. & MOON, W. 2015. Evolution of Class III treatment in orthodontics. American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics, 148, 22-36.

NUNES, W. R., JR. & DI FRANCESCO, R. C. 2010. Variation of patterns of malocclusion by site of pharyngeal obstruction in children. Arch Otolaryngol Head Neck Surg, 136, 1116-20.

PANGRAZIO-KULBERSH, V., BERGER, J. L., JANISSE, F. N. & BAYIRLI, B. 2007. Long-term stability of Class III treatment: rapid palatal expansion and protraction facemask vs LeFort I maxillary advancement osteotomy. Am J Orthod Dentofacial Orthop, 131, 7.e9-19.

PARK, Y.-C. & BURSTONE, C. J. 1986. Soft-tissue profile-fallacies of hard-tissue standards in treatment planning. American Journal of Orthodontics and Dentofacial Orthopedics, 90, 52-62.

PASCOE, J. J., HAYWARD, J. R. & COSTICH, E. R. 1960. Mandibular prognathism: its etiology and classification. J Oral Surg Anesth Hosp Dent Serv, 18, 21-4.

PAVONI, C., GAZZANI, F., FRANCHI, L., LOBERTO, S., LIONE, R. & COZZA, P. 2019. Soft tissue facial profile in Class III malocclusion: long-term post-pubertal effects produced by the Face Mask Protocol. Eur J Orthod, 41, 531-536.

PECK, H. & PECK, S. 1970. A concept of facial esthetics. Angle Orthod, 40, 284-318.

PHILLIPS, C., TRENTINI, C. J. & DOUVARTZIDIS, N. 1992. The effect of treatment on facial attractiveness. Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons, 50, 590-4.

POSPISIL, O. A. 1987. Reliability and feasibility of prediction tracing in orthognathic surgery. J Craniomaxillofac Surg, 15, 79-83.

POWELL & HUMPHREYS 1984. Proportions of the aesthetic face. New York: Thieme Stratton.

PROFFIT, W. R., HENRY W. FIELDS, DAVID M. SARVER. 2013. Contemporary orthodontics. 6th ed. St. Louis, Mo: Elsevier/Mosby.

PROFFIT, W. R., PHILLIPS, C. & TURVEY, T. A. 2012. Stability after mandibular setback: mandible-only versus 2-jaw surgery. J Oral Maxillofac Surg, 70, e408-14.

RA BAYS, A. H., DP TIMMIS . 1997. Maxillary Orthognathic surgery. In: Peterson LJ, ed. Principles of Oral and Maxil- lofacial Surgery. Philadelphia, Pa: Lippincott-Raven Publishers. 1373–1376.

RHODES, G., SUMICH, A. & BYATT, G. 1999. Are average facial configurations attractive only because of their symmetry? Psychological Science, 10, 52-58.

RHODES, G. & TREMEWAN, T. 1996. Averageness, exaggeration, and facial attractiveness. Psychological Science, 7, 105-110.

RHODES, G., YOSHIKAWA, S., CLARK, A., LEE, K., MCKAY, R. & AKAMATSU, S. 2001. Attractiveness of facial averageness and symmetry in non-Western cultures: In search of biologically based standards of beauty. Perception, 30, 611-25.

RICKETTS, R. M. 1957. Planning Treatment on the Basis of the Facial Pattern and an Estimate of Its Growth. The Angle Orthodontist, 27, 14-37.

RICKETTS, R. M. 1979a. Dr. Robert M. Ricketts on early treatment (part 1). Journal of clinical orthodontics: JCO, 13, 23-38.

RICKETTS, R. M. 1979b. Dr. Robert M. Ricketts on early treatment (part 2). Journal of clinical orthodontics: JCO, 13, 115-127.

RICKETTS, R. M. 1979c. Dr. Robert M. Ricketts on early treatment. (Part 3). Journal of clinical orthodontics: JCO, 13, 181-199.

RICKETTS, R. M. 1982. The biologic significance of the divine proportion and Fibonacci series. American Journal of Orthodontics, 81, 351-370.

RODRÍGUEZ DE GUZMÁN-BARRERA, J., SÁEZ MARTÍNEZ, C., BORONAT-CATALÁ, M., MONTIEL-COMPANY, J. M., PAREDES-GALLARDO, V., GANDÍA-FRANCO, J. L., ALMERICH-SILLA, J. M. & BELLOT-ARCÍS, C. 2017. Effectiveness of interceptive treatment of class III malocclusions with skeletal anchorage: A systematic review and meta-analysis. PloS one, 12, e0173875-e0173875.

RUSTEMEYER, J., EKE, Z. & BREMERICH, A. 2010. Perception of improvement after orthognathic surgery: the important variables affecting patient satisfaction. Oral and maxillofacial surgery, 14, 155-62.

SANBORN, R. T. 1955. Differences Between the Facial Skeletal Patterns Of Class III Malocclusion and Normal Occlusion. The Angle Orthodontist, 25, 208-222.

SEEHRA, J., FLEMING, P. S., MANDALL, N. & DIBIASE, A. T. 2012. A comparison of two different techniques for early correction of Class III malocclusion. Angle Orthod, 82, 96-101.

SHAW, W. C., ADDY, M. & RAY, C. 1980a. Dental and social effects of malocclusion and effectiveness of orthodontic treatment: a review. Community Dentistry and Oral Epidemiology, 8, 36-45.

SHAW, W. C., MEEK, S. C. & JONES, D. S. 1980b. Nicknames, teasing, harassment, and the salience of dental features among school children. Br J Orthod, 7, 75-80.

SHAW, W. C., REES, G., DAWE, M. & CHARLES, C. R. 1985. The influence of dentofacial appearance on the social attractiveness of young adults. Am J Orthod, 87, 21-6.

SINGH, G. D. 1999. Morphologic determinants in the etiology of class III malocclusions: a review. Clin Anat, 12, 382-405.

SINKO, K., JAGSCH, R., BENES, B., MILLESI, G., FISCHMEISTER, F. & EWERS, R. 2012. Facial aesthetics and the assignment of personality traits before and after orthognathic surgery. International Journal of oral and maxillofacial surgery, 41, 469-76.

STEINER, C. C. 1953. Cephalometrics for you and me. American Journal of Orthodontics and Dentofacial Orthopedics, 39, 729-755.

STEINER, C. C. 1959. Cephalometrics In Clinical Practice. The Angle Orthodontist, 29, 8-29.

STIRLING, J., LATCHFORD, G., MORRIS, D. O., KINDELAN, J., SPENCER, R. J. & BEKKER, H. L. 2007. Elective orthognathic treatment decision making: a survey of patient reasons and experiences. J Orthod, 34, 113-27; discussion 111.

STONER, M. M. 1955. A photometric analysis of the facial profile: A method of assessing facial change induced by orthodontic treatment. American Journal of Orthodontics and Dentofacial Orthopedics, 41, 453-469.

SUBTELNY, J. D. 1959. A longitudinal study of soft tissue facial structures and their profile characteristics, defined concerning underlying skeletal structures. American Journal of Orthodontics and Dentofacial Orthopedics, 45, 481-507.

SUGAWARA, J., ASANO, T., ENDO, N. & MITANI, H. 1990. Long-term effects of chin cup therapy on skeletal profile in mandibular prognathism. American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics, 98, 127-133.

TWEED, C. H. 1954. The Frankfort-Mandibular Incisor Angle (FMIA) In Orthodontic Diagnosis, Treatment Planning, and Prognosis. The Angle Orthodontist, 24, 121-169.

VARGO, J. K., GLADWIN, M. & NGAN, P. 2003. Association between ratings of facial attractiveness and patients’ motivation for orthognathic surgery. Orthodontics & craniofacial research, 6, 63-71.

VINCI, L. D. & PEDRETTI, C. 2001. Pedretti C. Leonardo da Vinci: Notebook of a Genius. Milan: Powerhouse Publishing.

WILLEMS, G., BRUYNE, I., VERDONCK, A., FIEUWS, S. & CARELS, C. 2002. Prevalence of dentofacial characteristics in a Belgian orthodontic population. Clinical oral investigations, 5, 220-6.

WOON, S. C. & THIRUVENKATACHARI, B. 2017. Early orthodontic treatment for Class III malocclusion: A systematic review and meta-analysis. American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics, 151, 28-52.

ZERE, E., CHAUDHARI, P. K., SHARAN, J., DHINGRA, K. & TIWARI, N. 2018. Developing Class III malocclusions: challenges and solutions. Clinical, cosmetic, and investigational dentistry, 10, 99-116.

ZHANG, M., MCGRATH, C. & HÄGG, U. 2006. The impact of malocclusion and its treatment on quality of life: a literature review. Int J Paediatr Dent, 16, 381-7.