Redefining Smile Design: Principles, Paradigms, and Clinical Application
Written by Dr. Agatha Bis
An Evidence-Based Synthesis of Contemporary Smile Design: Principles, Paradigms, and Clinical Application
Foreword: The Evolution from Dogma to Dynamic Design
The pursuit of an aesthetically pleasing smile is a desire that transcends cultures and millennia, with evidence of cosmetic dental modifications dating back to ancient civilizations.¹ The Etruscans fashioned dentures from ivory and bone held by gold bands around 700 BC, while ancient Egyptians used gold for crowns and bridges, and even attempted to whiten teeth with pumice and vinegar pastes.³ This long history underscores a fundamental human impulse to enhance appearance through the one aspect of the face we all focus on the most - the smile. However, the systematic, scientific approach to smile creation is a much more recent phenomenon. The journey of aesthetic dentistry has been one of profound evolution, moving from rudimentary practices and anecdotal observations to a sophisticated, evidence-based discipline.⁵
The 18th century marked a pivotal turning point with the work of Pierre Fauchard, the "Father of Modern Dentistry," who introduced foundational concepts that shifted dentistry toward a more scientific footing.⁷ The 20th century saw the emergence of pioneers who attempted to codify the principles of beauty. Figures like Williams, Pound, and Frush and Fisher developed guidelines for tooth shape, arrangement, and harmony with the face, often in the context of complete denture fabrication.⁶ These early efforts were frequently rooted in attempts to find universal, mathematically defined rules, most notably the application of the Golden Proportion (ϕ≈1.618) to dental aesthetics.⁵ This ratio, observed in art and nature, was proposed as a universal standard for creating harmonious tooth widths.¹¹
However, the contemporary paradigm of smile design represents a significant departure from this rigid, formulaic past. A wealth of modern research and clinical experience has demonstrated that while mathematical guidelines can serve as useful starting points, they lack universal applicability across diverse populations and fail to account for the beautiful variability inherent in nature.⁵ The modern philosophy, as detailed in this report, is one of individualization over standardization.⁵ It is a patient-centered, facially-driven, and fundamentally interdisciplinary approach. Success is no longer measured by adherence to a rigid set of numbers but by the artful integration of scientific principles, biomechanical function, material science, and the unique anatomical, physiological, and psychological characteristics of the individual patient.⁵
This report aims to provide a comprehensive, evidence-based synthesis of contemporary smile design. It will deconstruct the foundational principles, explore the scientific rationale behind their existence, and critically analyze their application in the complex realities of clinical practice. By navigating the transition from historical dogma to dynamic, digital design, this analysis will illuminate a discipline that stands at the intersection of art and science, capable of delivering predictable, beautiful, and long-lasting results that enhance both function and quality of life.⁵
Part I: The Foundational Principles of Aesthetic Smile Design
The creation of a harmonious smile is governed by a hierarchy of aesthetic principles that extend from the broad framework of the face to the intricate details of the teeth and their surrounding tissues. These principles are not immutable laws but rather a sophisticated set of diagnostic guidelines that allow the clinician to systematically evaluate, plan, and execute treatment. The modern approach to smile design is structured from the outside-in, beginning with the macro-aesthetic relationship of the smile to the face, proceeding to the mini-aesthetic dynamics of the lips and teeth, and concluding with the micro-aesthetic details of the dentogingival complex.¹⁶
Section 1.1: Macro-Esthetics: Integrating the Smile with the Facial Framework
The face provides the essential canvas upon which a smile is composed. A successful smile design must be in complete harmony with the patient's overall facial features; otherwise, even a technically perfect dental restoration will appear discordant and unnatural. A comprehensive facial analysis is therefore the mandatory first step in any aesthetic treatment plan.⁵
Facial Midline and Symmetry
The primary vertical reference for all smile design is the facial midline. This imaginary line, typically running through the glabella, tip of the nose, and centre of the chin, serves as the anchor for dental symmetry. The dental midline, defined by the contact point between the maxillary central incisors, should ideally coincide with this facial and skeletal midline.¹⁶ However, a critical finding from numerous perceptual studies is that perfect alignment is not a prerequisite for an acceptable aesthetic outcome. Research indicates that the general public typically does not perceive a dental midline deviation until it reaches 2 to 3 mm, although dental professionals tend to be more critical.⁵
Of far greater aesthetic importance than the precise location of the dental midline is its angulation. A midline that is parallel to the long axis of the face, even if slightly deviated laterally, is often acceptable. In contrast, a canted or inclined midline, where the incisors are visibly tilted, is a significant aesthetic discrepancy that is readily noticed and perceived as unattractive by laypeople, even with a deviation as small as 2 mm.¹⁸ The philtrum of the upper lip is a key anatomical landmark for this assessment; a dental midline that bisects the philtrum is generally perceived as harmonious, and a discrepancy between the philtrum and the interdental papilla often points to a true midline deviation rather than a simple incisal inclination problem.¹⁶
Inter-pupillary Line
The primary horizontal reference is the inter-pupillary line, the line connecting the centres of the pupils. In a well-balanced face, this line should be parallel to the horizon and, crucially, to the occlusal and incisal planes of the teeth.¹⁶ Any deviation from this parallelism results in an occlusal cant, which is one of the most distracting and aesthetically disruptive problems in smile design. It creates an immediate sense of imbalance and asymmetry that is difficult for the observer's eye to ignore. The accurate assessment of this relationship is fundamental, and modern digital tools, such as a virtual facebow integrated into Digital Smile Design (DSD) software, have become instrumental in diagnosing and planning the correction of occlusal cants.²⁰
Facial Proportions
Classical aesthetic principles, some dating back to antiquity, provide a framework for evaluating overall facial harmony. These include dividing the face into vertical thirds (from the hairline to the browline, from the browline to the base of the nose, and from the base of the nose to the chin) and horizontal fifths (with the width of the face being approximately five times the width of one eye).¹⁶ While these are not rigid rules to be dogmatically applied to every patient, they serve as valuable diagnostic aids. Significant deviations from these proportions can influence the perception of the smile and may guide decisions regarding the vertical dimension of occlusion or the overall width of the dental arch required to achieve a balanced result.
Section 1.2: Mini-Esthetics: The Dynamics of Lip-Tooth Relationships
Mini-esthetics focuses on the "display zone" of the smile, the components framed by the upper and lower lips. The dynamic interplay between the lips and the teeth is arguably the most influential factor in determining a smile's perceived attractiveness and vitality.¹⁶
Smile Arc Consonance
The smile arc is defined as the relationship between the curvature of the incisal edges of the maxillary anterior teeth and the curvature of the inner border of the lower lip during a social smile.⁵ This is one of the most critical principles of modern smile design, and it’s often simply referred to as the smile line. A consonant smile arc, where the curve of the teeth parallels the curve of the lower lip, is consistently rated by both professionals and laypeople as the most attractive, youthful, and harmonious.⁵ Recent studies continue to validate this preference, with a 2023 study finding that patients undergoing orthodontic treatment overwhelmingly preferred a convex (consonant) smile arc.²⁶
Conversely, a flat smile arc, where the incisal curve is straighter than the lower lip, can create a less dynamic and more aged or aggressive appearance.²³ A reverse smile arc, where the incisal curve is convex superiorly (opposite to the lower lip), is almost universally perceived as unattractive and is a common consequence of excessive incisal wear. Orthodontic treatment is frequently aimed at establishing or improving the smile arc, with studies showing a significant increase in the prevalence of consonant arcs post-treatment.¹² It is important to note, however, that the two-dimensional nature of standard photographs can introduce diagnostic errors; research has shown that changes in head inclination can alter the perceived consonance of the smile arc, underscoring the value of standardized photography or three-dimensional analysis.²⁴
Incisal Display
The amount of maxillary tooth structure visible is a key indicator of age. At rest, a youthful smile is characterized by the display of 3 to 4 mm of the incisal edges of the central incisors.¹⁸ This display naturally decreases with age due to soft tissue sagging and/or incisal wear, potentially reaching 1 mm or less in a 60-year-old.²⁸ Clinically, the amount of resting tooth display can be assessed by having the patient repeat the "M" sound and observing the teeth as the lips return to a relaxed position.¹⁶ The "E" sound is another useful phonetic test, as the ideal incisal edge position should be approximately halfway between the upper and lower lips during its pronunciation.¹⁶ The amount of tooth reveal is a foundational decision in smile design, as it dictates the necessary tooth length and influences the perceived youthfulness of the final result.¹⁷
Smile Line (Gingival Display)
The smile line refers to the vertical relationship of the upper lip to the maxillary teeth and gingiva during a full smile. It is typically categorized into three types¹²:
High Smile Line: The upper lip moves significantly superiorly, exposing the full length of the maxillary teeth as well as a continuous band of gingiva. When this gingival display is excessive, it is often termed a "gummy smile."
Average Smile Line: The upper lip elevates to expose the full clinical crowns of the anterior teeth, along with the inter-proximal gingiva (papillae). This is generally considered the most conventional and desirable smile line.
Low Smile Line: The upper lip shows limited mobility, revealing less than 75% of the anterior teeth.
While the average smile line is often held as the ideal, aesthetic preferences can vary significantly. A 2024 study of university students found that nearly 51% chose a low smile line as the most attractive, compared to 34.6% for an average smile line.²⁵ This highlights the importance of patient-centered diagnosis over rigid adherence to a single standard. The management of an unaesthetic smile line, particularly a gummy smile, is a complex clinical challenge that often requires an interdisciplinary approach. Depending on the etiology, which can range from altered passive eruption to vertical maxillary excess or a hypermobile lip, treatment may involve periodontal surgery (crown lengthening/gingivectomy), orthodontics, or even orthognathic surgery.¹¹
Buccal Corridors
The buccal corridors are the negative spaces that appear between the buccal surfaces of the posterior teeth and the corners of the mouth during a full smile.¹⁷ The ideal size of these corridors is a subject of some debate and can be influenced by cultural preferences.¹⁹ However, excessively wide or "empty" buccal corridors can create the illusion of a narrow dental arch or missing posterior teeth, resulting in a less full and vibrant smile.¹⁷ Conversely, completely eliminating the buccal corridors can lead to a "toothy" or denture-like appearance. The goal is to achieve a balance that provides a full, broad smile without appearing artificial. This is typically managed through orthodontic arch expansion or by carefully designing the width and contour of posterior restorations.
Section 1.3: Micro-Esthetics: The Architecture of Teeth and Gingiva
Micro-esthetics involves the analysis and design of the finest details of the individual teeth and their gingival framework. It is at this level that the clinician's artistic sensitivity and technical precision are most critical, as minor imperfections can have a major impact on the final outcome.⁵
Tooth Proportions and Dimensions
The proportional relationship between teeth is a cornerstone of micro-aesthetic design. While several mathematical formulas have been proposed, their clinical application requires careful judgment and individualization.
Width-to-Length Ratio and Central Dominance: The most important proportional relationship is the width-to-length (W/L) ratio of the maxillary central incisors. These teeth must be the dominant element in the smile.¹⁶ An aesthetically pleasing central incisor typically has a W/L ratio of approximately 75% to 80% (or 0.75–0.80).¹⁶ Ratios outside this range can make the teeth appear too square or too narrow. Once the ideal dimensions of the central incisors are established, they serve as the reference for designing the rest of the anterior sextant.
The Golden Proportion (φ): Historically, the Golden Proportion (ϕ≈1.618) was a popular guideline, suggesting that the perceived width of the lateral incisor should be 62% of the central, and the canine 62% of the lateral.⁵ However, a significant body of modern scientific evidence has refuted the universal applicability of this rule. Systematic reviews and numerous studies across different ethnic populations have consistently failed to find the Golden Proportion in natural, aesthetically pleasing dentitions.⁵ For example, one study in a Saudi population found that Golden Proportion values were statistically different from the standard, with only 16.5% matching for the right lateral incisor and a mere 1% for the right canine.³⁰ These findings strongly suggest that while the Golden Proportion can be used as a conceptual starting point, rigid adherence is clinically inappropriate and can lead to unnatural-looking results, particularly the creation of overly small lateral incisors.⁵
Recurring Aesthetic Dental (RED) Proportion and Golden Percentage: As alternatives, the RED proportion, which proposes a constant percentage (e.g., 70–80%) for successive tooth widths, and the Golden Percentage, which assigns specific percentages of the inter-canine width to each tooth (e.g., centrals 25%, laterals 15%, canines 10%), have been suggested.¹⁰ However, like the Golden Proportion, their universal validity is highly questionable and population-dependent. Studies have found that these theories are often not applicable across different ethnic groups.⁵ The clinical takeaway is to use these proportions as flexible guidelines rather than absolute mandates, prioritizing overall harmony and individual patient anatomy over a mathematical formula.⁵
Gingival Architecture
The health and architecture of the gingival tissues are as important as the teeth themselves. An otherwise perfect restoration can be an aesthetic failure if framed by inflamed, asymmetrical, or poorly contoured gums.¹⁶ Key parameters include:
Gingival Levels and Harmony: In an ideal smile, the gingival margins of the two central incisors are symmetrical and at the same vertical level as the canines. The gingival margins of the lateral incisors are positioned slightly more incisally (coronally), typically by 0.5 to 1.0 mm.⁵ This subtle scalloped effect creates a harmonious and natural flow.
Gingival Zenith: The zenith is the most apical point of the free gingival margin. Its position along the tooth's long axis is critical for creating the illusion of correct tooth shape and angulation. For the maxillary central incisors and canines, the zenith should be located slightly distal to the tooth's vertical long axis. For the lateral incisors, the zenith is typically more centered or coincident with the long axis.⁵ Manipulating the zenith position through minor surgical contouring (gingivoplasty) is a powerful tool, for instance, in diastema closure cases, to make teeth appear less triangular and more ideally aligned.¹⁶
Axial Inclinations
The perceived vertical alignment of the anterior teeth should not be perfectly parallel. For a dynamic and harmonious appearance, the teeth should exhibit a slight mesial inclination that becomes progressively more pronounced from the central incisors to the canines. This creates a pleasing convergence toward the dental midline and contributes to a natural, non-static aesthetic.¹⁶
Interdental Contacts and Embrasures
The character of the spaces between the teeth is defined by the contact areas and the embrasure forms. The interdental contact point between the central incisors is the longest and most incisally located. Moving distally, the contact points become shorter and migrate more apically. This progression creates the incisal embrasures, the small, V-shaped spaces between the incisal edges of adjacent teeth. The size of these embrasures should gradually increase from the central-lateral contact to the lateral-canine contact.⁵ Properly formed incisal embrasures are a hallmark of a youthful, natural dentition; their absence or blunting leads to a ‘boxy’, monotonous, and artificial appearance.⁵
The principles of smile design form a complex yet logical framework. They are not merely a collection of isolated rules but an interconnected hierarchy. A clinical decision made at the macro-aesthetic level, such as the orthodontic correction of a canted occlusal plane, will inevitably cascade downward, fundamentally altering the requirements at the mini-aesthetic level (e.g., the smile arc) and the micro-aesthetic level (e.g., the final position of the gingival zeniths). For instance, a clinician might identify a flat smile arc as a primary aesthetic concern. The root cause, however, may not lie within the teeth themselves but in an underlying skeletal issue, such as an incorrectly angulated maxillary occlusal plane. By addressing this macro-aesthetic problem first through orthodontics or orthognathic surgery,²² the smile arc is often automatically improved. This corrective movement, in turn, repositions the gingival margins relative to the lips. Consequently, the final micro-aesthetic plan for gingival contouring or veneers cannot be definitively established until the macro- and mini-aesthetic foundations have been correctly set. This demonstrates that the "rules" are not a static checklist but a dynamic, sequential diagnostic and treatment planning protocol. The modern "esthetics-first" treatment planning philosophy, which begins by defining the ideal final tooth position and smile design before determining the necessary biological and functional interventions, is a direct embodiment of this hierarchical logic.¹⁸
| Parameter | Ideal Guideline | Clinically Acceptable Range / Common Deviations | Key Clinical Considerations & Supporting Evidence |
|---|---|---|---|
| MACRO-ESTHETICS | |||
| Facial & Dental Midline | Coincident; parallel to facial long axis. | 0–3 mm lateral deviation tolerated by laypeople. | Angulation (cant) is more critical than position. A 2 mm cant is perceptible and unesthetic. The philtrum is a key guide. 5 |
| Interpupillary & Occlusal Plane | Parallel. | No deviation is aesthetically acceptable. | A canted occlusal plane is a major aesthetic discrepancy. Requires accurate diagnosis with tools like a virtual facebow. 16 |
| MINI-ESTHETICS | |||
| Smile Arc | Consonant (maxillary incisal curve parallels lower lip curve). | Flat smile arc (common with age/wear); Reverse smile arc (highly unesthetic). | Consistently rated as more youthful and attractive. Perception can be altered by head tilt in 2D photos. 5 |
| Incisal Display at Rest | 3–4 mm in young adults. | Decreases with age to 0–1 mm. | Key indicator of youth. Assessed with “M” sound. Dictates required tooth length in the final design. 17 |
| Smile Line (Gingival Display) | Average: Full tooth display with visible papillae. | High: “Gummy smile.” Low: <75% tooth display. | Preference varies; some prefer a low smile line. Gummy smile correction is often interdisciplinary. 11 |
| Buccal Corridors | Small, visible negative space. | Excessively wide (“hollow”) or absent (“toothy”). | Provides smile with depth and breadth. Ideal size is debated; may be influenced by arch form and cultural preference. 17 |
| MICRO-ESTHETICS | |||
| Central Incisor W/L Ratio | ~78% (Width is 75–80% of length). | 75–85% is generally acceptable. | Establishes “central dominance,” the key to the smile. The foundation for sizing other anterior teeth. 16 |
| Anterior Tooth Proportions | Varies by ethnicity and individual anatomy. | Rigid adherence to Golden Proportion, RED, or Golden Percentage. | Mathematical formulas are NOT universal standards; evidence refutes their consistent presence in nature. 5 |
| Gingival Levels | Centrals & Canines at same level; Laterals 0.5–1.0 mm coronal. | Asymmetrical or flat gingival line. | Creates a harmonious gingival scallop; essential for a natural appearance. 5 |
| Gingival Zenith Position | Distal to long axis for Centrals/Canines; centered for Laterals. | All zeniths centered or incorrectly positioned. | Creates illusion of proper tooth shape and inclination; crucial for refined esthetics. 5 |
| Axial Inclinations | Progressive mesial tilt from centrals to canines. | Parallel or divergent axes. | Creates harmony and convergence toward the midline. 16 |
| Incisal Embrasures | Size increases progressively from central to canine. | Blunted or absent embrasures. | Creates separation and individuality of teeth; hallmark of a youthful, non-artificial smile. 5 |
Part II: The Scientific Rationale: Why the Rules Exist
The principles of smile design are not arbitrary aesthetic preferences. They are, in fact, clinical manifestations of underlying laws in biomechanics, perceptual psychology, and optical physics. Understanding the scientific rationale, the "why" behind each rule, is what elevates the practice of aesthetic dentistry from a technical craft to a sophisticated clinical science. This knowledge empowers clinicians to make more informed decisions, predict outcomes with greater accuracy, and create restorations that are not only beautiful but also durable and biologically integrated.
Section 2.1: Biomechanical Principles: Function as the Bedrock of Esthetics
An aesthetically pleasing smile that is not built upon a foundation of functional stability is destined to fail. Many of the "rules" of smile design are visual proxies for a healthy, well-functioning occlusal system. Lasting esthetics are inextricably linked to proper biomechanics.⁵
Anterior Guidance and Occlusal Stability
One of the most critical functions of the anterior teeth is to provide anterior guidance. Assuming that the mandible is in the correct Optimal Physiologic Position (OPP), during protrusive and lateral movements of the mandible, the contacts between the lower incisors and the palatal surfaces of the upper anterior teeth should cause the posterior teeth to separate, or "disclude".⁵ This mechanism protects the posterior teeth and their restorations from destructive, off-axis lateral forces during chewing. The "pleasing" curve of a consonant smile arc is often the direct visual representation of the functional envelope of motion required for this smooth, non-interfering guidance. A smile designed without regard for anterior guidance may look beautiful on a static model but can lead to chipping, fracture, or wear of both the restorations and the opposing dentition in a dynamic, functional environment.
Overbite and Overjet
The ideal parameters for overbite (vertical overlap) and overjet (horizontal overlap), typically cited as 2–3 mm, are not merely aesthetic guidelines.⁵ These dimensions are functionally critical. An appropriate overbite/overjet relationship is essential for establishing immediate and effective anterior guidance.
Excessive overbite often results in significant wear of the mandibular incisors. This occurs because a deep overbite typically places the mandible in a retruded position, and the muscles instinctively attempt to bring it forward. In doing so, the anterior teeth are forced into contact and subjected to grinding forces. Conversely, insufficient overbite is commonly associated with excessive anterior vertical dimension, often due to lingually inclined posterior teeth and/or constricted arches. This creates an anterior open bite with inadequate canine guidance, eliminating posterior disclusion and leaving posterior teeth in prolonged contact during function.
Similarly, proper overjet is necessary to allow clearance for the mandible to move forward without interference. Therefore, restoring these parameters correctly is fundamental to the long-term health and stability of the entire masticatory system.
Section 2.2: The Science of Perception: Evolutionary Psychology and Visual Harmony
The reason certain smiles are perceived as beautiful is not arbitrary; it is deeply rooted in the wiring of the human brain, shaped by evolutionary pressures and the fundamental principles of visual perception.
Evolutionary Cues of Health and Fitness
Evolutionary psychology proposes that our standards of beauty are not merely cultural constructs but are, in part, adaptations for identifying healthy and fertile mates.³⁸ Features that are universally considered attractive, such as facial symmetry, clear skin, and vibrant hair, are "honest signals" of underlying genetic quality, developmental stability, and a robust immune system. A healthy, attractive smile fits squarely into this framework. Teeth that are well-aligned, free of decay, and have a healthy colour are powerful, subconscious indicators of youth, health, and good developmental history. Therefore, when a clinician designs a smile that embodies these characteristics, they are not just creating an aesthetic preference; they are tapping into a deep-seated, evolved psychological mechanism that equates this appearance with vitality and desirability.³⁸
The Psychology of Symmetry and Balance
The human brain is a pattern-seeking organ, hardwired to find harmony, balance, and order in visual information. This is why symmetry is such a powerful aesthetic principle.¹⁴
Static Symmetry: This refers to a mirror-image relationship. In smile design, it is applied almost exclusively to the maxillary central incisors. When these two teeth are perfect mirror images of each other, they create a strong, stable anchor at the centre of the smile, which is the area of greatest visual attraction.¹⁴
Dynamic Symmetry: This concept describes elements that are similar in form and size but not identical. It is the guiding principle for the teeth distal to the centrals. The right lateral incisor should be harmonious with the left, but not a perfect mirror image. The same applies to the canines. This subtle variation, often called "perfect imperfection," is what gives a smile life, vitality, and a natural appearance. Over-application of static symmetry to all the anterior teeth results in a monotonous, artificial, "denture-like" look that is aesthetically displeasing.¹⁴
Visual Perception and Weight
Principles from the world of art explain how different elements within a composition draw the viewer's attention. A key concept is "visual weight." Lighter, brighter, and larger objects have more visual weight and command more attention.¹⁴ In the context of the smile, the teeth are white objects set against the relatively dark background of the oral cavity. This high contrast gives them significant visual weight, drawing the viewer's eye immediately when a person smiles. Within the dental arch, the central incisors are the largest and typically brightest teeth, giving them the most visual weight. This is the perceptual science behind the principle of central dominance. If the central incisors are not appropriately dominant in size and position, the entire composition of the smile feels unbalanced and aesthetically compromised.¹⁶
Section 2.3: The Science of Color and Light: Achieving Natural Vitality
Achieving a truly lifelike restoration requires more than just matching a shade on a commercial guide. It demands a deep understanding of colour science and the complex ways in which light interacts with natural tooth structure. A failure to replicate these subtle optical properties is often what separates an acceptable restoration from an imperceptible one.³⁹
The Three Dimensions of Color
Color is a three-dimensional phenomenon, most commonly described in dentistry using the Munsell colour system's parameters: hue, chroma, and value.⁴⁰
Hue: This is the basic colour family (e.g., A-range is reddish-brown, B-range is reddish-yellow in the VITA Classical shade guide).⁴¹
Chroma: This is the saturation or intensity of the hue. A high-chroma tooth appears richer in colour, while a low-chroma tooth is more muted.
Value: This is the lightness or darkness of the tooth, on a scale from pure white to pure black. Value is independent of hue and chroma and is widely considered the most critical dimension in shade matching. The human eye is far more sensitive to small differences in value than to subtle shifts in hue or chroma. An incorrect value match will be immediately obvious, making the restoration appear either too bright or too grey, while a minor hue mismatch may go unnoticed.⁴²
Critical Optical Phenomena for Lifelike Restorations
Natural teeth possess unique optical properties that must be replicated in restorative materials to achieve a vital, natural appearance.
Translucency and Opacity: Natural tooth structure is not monolithic. The outer enamel layer is highly mineralized and relatively translucent, allowing light to pass through it. The underlying dentin is more opaque and contains the majority of the tooth's pigment, providing its basic hue and chroma.⁴³ This layered structure creates an optical effect of depth and vitality. Light enters the enamel, scatters within the dentin, and is reflected back out, creating a complex and dynamic appearance. Restorative dentistry must mimic this. High-end ceramic systems are layered, with an opaque core or dentin layer covered by a more translucent enamel layer.⁴³ A common clinical error is under-preparation of the tooth, which leaves insufficient space for these layers. This forces the dental technician to use an overly thick layer of opaque porcelain to block out the underlying tooth colour or cement, resulting in a restoration that looks flat, lifeless, and "chalky."⁴²
Fluorescence: Natural dentin contains organic components that absorb invisible ultraviolet (UV) light and re-emit it as visible light, typically in the blue end of the spectrum.³⁹ This phenomenon, called fluorescence, makes teeth appear brighter and more "alive," especially in environments with high UV content, like natural daylight. Restorations that lack fluorescent agents can appear grey, dark, or "dead" under these lighting conditions compared to the adjacent natural teeth. Therefore, modern restorative materials must incorporate fluorescing agents to properly mimic this vital property.
Opalescence: This is a complex optical effect exhibited by enamel. The fine hydroxyapatite crystals in enamel scatter shorter wavelengths of light (blue) more readily, while allowing longer wavelengths (orange, amber) to pass through. This results in the tooth appearing slightly bluish in reflected light (especially at the incisal edge, creating a "halo" effect) and appearing more amber or orange in transmitted light.⁴¹ This subtle play of colour is a key characteristic of a youthful, natural incisor and is a feature that master ceramists strive to replicate in their restorations.
Metamerism: This is a critical clinical challenge where two objects (e.g., a ceramic crown and a natural tooth) appear to be a perfect colour match under one light source but look different under another.³⁹ This occurs because the objects have different spectral reflectance curves. A match achieved under the warm, yellow-rich light of a dental operatory's incandescent lamp may be a significant mismatch under the cool, blue-green spectrum of an office's fluorescent lighting or in natural daylight. The clinical protocol to overcome metamerism is to perform the shade selection under multiple, varied light sources, including natural daylight if possible. A shade that is an acceptable, if not perfect, match under all lighting conditions is preferable to one that is a perfect match under only one.³⁹
The convergence of these scientific fields provides a profound understanding of why the principles of smile design exist. The "rule" to create a consonant smile arc, for example, is not just about aesthetics. The initial reason is that it is perceived as more attractive.²³ A deeper reason is that this curve often represents the functional envelope of motion required for proper anterior guidance, which protects the entire occlusal system from biomechanical failure.⁵ Furthermore, the ceramic materials used to create this arc have specific biomechanical strength requirements, validated by FEA, that dictate the necessary tooth preparation.³³ At the highest level, a healthy, functional smile is an evolutionary signal of youth and vitality, which is why our brains are perceptually wired to find it attractive in the first place.³⁸ Thus, a single aesthetic guideline represents a convergence point for biomechanics, materials science, and evolutionary psychology. This multi-layered understanding transforms the clinician from a technician following rules into a scientist and artist applying integrated principles.
Part III: Clinical Application and the Art of Compromise
While the principles of smile design provide an essential theoretical framework, their application in the clinical environment is rarely straightforward. The reality of daily practice is one of navigating anatomical variations, biological limitations, patient expectations, and functional demands. True mastery in aesthetic dentistry lies not in the rigid application of rules, but in the artful ability to adapt these principles to the unique circumstances of each patient, understanding when to compromise and when to hold firm, and collaborating effectively with both the patient and an interdisciplinary team.¹⁴
Section 3.1: The Limits of Ideals: Navigating Anatomical and Biological Constraints
The "ideal" smile described in textbooks often presumes an ideal starting point, a patient with a healthy periodontium, a Class I skeletal relationship, and minimal tooth wear. In reality, many patients seeking aesthetic improvement present with significant underlying challenges that make a textbook outcome impossible without extensive, and sometimes undesired, preliminary treatment.⁴⁶
Common clinical scenarios that require a departure from ideal principles include:
Skeletal Discrepancies: A patient with a significant Class II (retrognathic mandible) or Class III (prognathic mandible) jaw relationship presents a compromised canvas. Achieving ideal overjet, overbite, and axial inclinations with restorations alone may be impossible or functionally disastrous. The ideal treatment would involve BiteAlign™ , orthodontics, and potentially orthognathic surgery to correct the underlying problem first.¹⁸ If the patient declines this, the restorative plan becomes one of compromise, balancing aesthetic goals with the functional limitations of the malocclusion.
Severe Tooth Wear and Loss of Vertical Dimension: Patients with advanced attrition or erosion often present with shortened clinical crowns, a flat or reverse smile arc, and a collapsed vertical dimension of occlusion (VDO).⁴⁷ A full-mouth rehabilitation is required, but simply lengthening the teeth is not an option. The VDO must be carefully re-established, often requiring treatment of every tooth in the mouth. The "Smile Design and Space (SDS)" concept is a modern approach to managing these complex cases, integrating aesthetic planning with the functional requirements of altering the VDO.⁴⁸
Congenitally Missing or Malformed Teeth: The classic example is the "peg lateral," a conical or undersized maxillary lateral incisor.⁴⁹ Restoring a peg lateral to ideal proportions is often complicated by spacing issues. If there is a diastema, simply enlarging the lateral can create a disproportionately wide tooth. The ideal solution is often orthodontic treatment to reapportion the space across the anterior sextant, allowing for a more harmoniously sized restoration.⁴⁹
Compromised Periodontal Foundations: A patient with bone loss, gingival recession, or large "black triangles" (open gingival embrasures) presents a significant aesthetic challenge.⁴⁶ Restorations must be designed around the existing soft tissue framework. While periodontal procedures like soft tissue grafting can improve the foundation, there are limits to what can be achieved, especially in cases of advanced periodontal disease.²⁹ The final smile design must accept and work within these biological constraints.
Section 3.2: The Acceptable Deviation vs. The Aesthetic Failure: A Risk-Based Analysis
Clinical judgment is paramount in deciding when a deviation from a guideline is an acceptable, imperceptible compromise versus when it constitutes an aesthetic or functional failure. This decision-making process is risk-based and should be guided by an understanding of patient perception and functional consequences.
Perception Thresholds and Visual Impact
The key to intelligent compromise is to understand what patients actually see. As previously discussed, the difference in perception between laypeople and dental professionals is significant.⁵ A clinician might be troubled by a 1 mm midline deviation, but research confirms this is well below the perception threshold for most patients.⁵ Therefore, embarking on complex treatment solely to correct such a minor deviation may represent over-treatment. In contrast, a 2 mm cant in the axial inclination of the central incisors is readily perceived by laypeople and is considered unaesthetic.¹⁸ The clinical implication is to focus resources and effort on correcting deviations that have the highest visual impact (e.g., cants, reverse smile arcs, value mismatches) while accepting minor deviations in less critical areas (e.g., precise midline location, perfect adherence to the Golden Proportion).
Functional vs. Aesthetic Compromise
The ultimate dividing line between an acceptable deviation and a failure is function. A deviation is unacceptable if it compromises the biomechanical integrity or long-term health of the dentition. For example:
Unacceptable Compromise: Violating the minimum required thickness for an all-ceramic restoration to achieve a more "conservative" preparation. While it may look acceptable at delivery, it creates high stress concentrations and significantly increases the risk of catastrophic fracture.⁴⁵ This is a functional failure.
Acceptable Compromise: Deviating from a strict 78% width-to-length ratio for a central incisor to achieve an 82% ratio in order to close a small diastema without orthodontics. If the result is harmonious with the patient's face and functionally sound, this is an acceptable aesthetic compromise.
When complications or failures do occur, a systematic approach to management is required. This begins with a thorough diagnosis to identify the root cause, which could be a technical error (e.g., improper bonding), a material failure, or a patient-related factor (e.g., bruxism).⁵¹ Management strategies range from conservative approaches, such as polishing or minor restorative adjustments, to more invasive interventions like surgical revision of an implant or complete replacement of the failed restoration.⁵¹
Section 3.3: The Patient-Centered Paradigm: Co-Designing the Smile and Managing Expectations
In modern aesthetic dentistry, effective communication is arguably the most critical determinant of success. The ultimate goal is to create a result that not only meets clinical standards of excellence but also fulfills the patient's subjective desires and expectations. This requires a paradigm shift from the dentist as a unilateral decision-maker to the dentist as a collaborative partner in a co-design process.⁵²
Active Listening and Collaborative Goal Setting
It starts with a real conversation. Not a checklist, not a rushed Q&A, but an open dialogue that gets to the point of what the patient actually wants. I’ll usually say something like, “What’s bugging you the most about your teeth or your bite?” or “Is there anything you thought about changing or improving when it comes to your smile?” Those kinds of questions cut through the fluff and let the patient explain their concerns in plain language.⁵⁵ Listening here isn’t passive, it means watching how they answer, noticing tone and body language, and repeating back what you’ve heard so they know you get it. That’s where trust begins.⁵³ Beyond the clinical details, it’s just as important to dig into the “why.” Is this about feeling more confident at work? Finally taking care of self after spending a lifetime taking care of others? Once you understand what’s driving them, you can design a treatment plan that actually makes sense, for their mouth and for their life.⁵⁶
The Power of Visualization: DSD and the "Trial Smile"
The single most powerful tool for bridging the gap between the patient's abstract desires and the clinician's concrete plan is visualization. This is the core benefit of the Digital Smile Design (DSD) workflow.⁵⁷ The process involves:
Digital Planning: Using photos and digital scans, the dentist creates a 2D or 3D virtual simulation of the proposed new smile, allowing the patient to see the potential outcome before any treatment begins.⁴⁸
The Mock-Up or "Trial Smile": Based on the digital plan, a physical mock-up is created (typically from a 3D-printed model and a silicone index) and placed directly over the patient's unprepared teeth using a temporary material.⁵⁹ This allows the patient to "test-drive" their new smile in their own face, assessing its appearance, feel, and even its effect on their speech.
This process is transformative for patient communication. It makes the abstract tangible, empowers the patient to provide specific feedback ("Can the laterals be a little more rounded?"), and ensures true informed consent.⁶³ By aligning expectations before irreversible procedures are performed, it dramatically increases case acceptance and final patient satisfaction.⁵⁷
Managing Expectations in the Age of Social Media
The rise of social media platforms like Instagram and TikTok has created a new and significant challenge: the "social media smile."⁶⁵ Patients are inundated with images of perfectly white, symmetrical smiles on influencers and celebrities, often achieved with filters or aggressive, non-ideal dentistry. This creates a "knowledge gap," where patients arrive with unrealistic expectations, desiring a specific look without understanding the necessary underlying biological and functional requirements.⁶⁵ A systematic review found that social media exposure is significantly correlated with increased interest in cosmetic procedures and body dissatisfaction.⁶⁷
The clinician's role is to gently but firmly manage these expectations through education. The consultation must clearly explain why pre-existing health issues like cavities or periodontal disease must be addressed before any cosmetic work can begin.⁶⁵ It is an opportunity to discuss why the "Hollywood" veneer look may not be appropriate for their specific facial structure, lip dynamics, or long-term oral health. The DSD and mock-up process is invaluable here, as it can visually demonstrate how a more natural, individualized design is often more harmonious and beautiful than a generic, overly bright ideal.⁵⁶
Section 3.4: The Interdisciplinary Mandate: The Dentist as "Architect"
The most complex and rewarding aesthetic transformations are rarely the work of a single practitioner. Achieving optimal outcomes in challenging cases necessitates a well-coordinated, interdisciplinary team approach.²⁹
The Team Approach and the Role of the Dentist
The dentist serves as the “architect” of the comprehensive treatment plan, establishing the optimal design and restorative vision. It is the dentist’s role to coordinate and direct the sequence of care, ensuring that any specialists involved carry out their part in alignment with the overall plan. Ultimately, the dentist is responsible for the outcome. If the final result falls short, the patient does not turn to the surgeon or periodontist for answers, they hold the dentist accountable. For this reason, the dentist must remain in control of the process, providing clear instructions and guidance to all specialists involved so that the treatment is cohesive and the final result meets the patient’s expectations. Executing a comprehensive treatment plan frequently requires the expertise of other specialists.¹⁸
The Orthodontist: To move teeth into the correct position, create ideal space for restorations, correct bite problems, and perfect the smile arc.
The Periodontist: To manage the soft tissue framework, perform crown lengthening to correct gingival levels, place soft tissue grafts to cover recession, and develop ideal implant sites.
The Oral and Maxillofacial Surgeon: To place dental implants and perform orthognathic surgery to correct underlying skeletal discrepancies.
The "Esthetics-First" Interdisciplinary Workflow
The modern paradigm for interdisciplinary planning is the "esthetics-first" or "facially-driven" approach.¹⁸ This reverses the traditional treatment planning sequence. Instead of starting with biological problems and working toward an aesthetic result, the process begins by designing the ideal final aesthetic outcome, typically using DSD. This final design then dictates the specific objectives for each specialty. For example, the DSD plan might reveal that to achieve the ideal central incisor proportions, 2 mm of clinical crown lengthening (a periodontal procedure) is needed, and the lateral incisors must be orthodontically intruded by 1.5 mm. This "backward planning" ensures that all intermediate treatments are precisely targeted toward achieving a pre-visualized, mutually agreed-upon final goal.⁵⁰
The Crucial Dentist-Technician Collaboration
The relationship between the clinician and the dental laboratory technician is the cornerstone of all indirect restorative dentistry.⁷⁴ Inadequate communication is a primary source of remakes and aesthetic failures.⁷⁶ The digital revolution has profoundly enhanced this collaboration. Instead of relying on written prescriptions and physical models, clinicians can now instantly send digital scans and high-quality photographs to the lab. The dentist and technician can then review the digital design together in real-time via screen sharing, making adjustments to tooth morphology, contacts, and contours before any material is ever milled or pressed. This seamless, visual communication minimizes errors, improves predictability, and fosters a true team approach to creating beautiful restorations.⁷⁶
The rise of sophisticated patient communication strategies and interdisciplinary planning is not a random trend. It is a direct and necessary clinical adaptation to the collision of two powerful, opposing forces. On one side, the pervasive influence of social media has dramatically elevated patient awareness and aesthetic demands, often creating unrealistic expectations for "perfect" smiles.⁶⁵ On the other side, a deeper and more mature clinical understanding, grounded in decades of scientific research and experience, has taught the profession that perfect symmetry is unnatural and that absolute ideals are frequently constrained by the patient's unique biology and anatomy.¹⁸ This collision creates a significant "expectation gap" between what the patient desires and what is clinically achievable or advisable. If this gap is left unmanaged, it will inevitably lead to patient dissatisfaction, even in the face of a technically excellent clinical result.
Therefore, the profession has evolved specific tools and protocols to bridge this gap. Digital Smile Design and the physical mock-up are not just for technical planning; they are powerful communication instruments designed to manage expectations and facilitate co-diagnosis.⁵⁹ The growing emphasis on interdisciplinary care is a direct recognition that the complex demands of the modern aesthetic patient often exceed the capabilities of any single dental discipline.²⁹ Consequently, the modern focus on "soft skills," patient-centered communication, and team-based planning is not a separate or secondary aspect of aesthetic dentistry; it is a fundamental and necessary adaptation to the pressures of the contemporary clinical environment.
Table 2: Interdisciplinary Management of Common Aesthetic Challenges
| Esthetic Dilemma | Primary Diagnosis | Contributing Factors | Restorative-Only Solution (and its Limitations) | Ideal Interdisciplinary Approach |
|---|---|---|---|---|
| Gummy Smile | Excessive gingival display during full smile. |
|
Crowns/Veneers: Can lengthen teeth, but only if tooth proportion allows. Does not address the underlying cause and can result in overly long, unesthetic teeth. Limitation: Fails to correct the lip–gingiva relationship. | Perio: Crown lengthening/gingivectomy for APE. Ortho: Intrusion of over-erupted incisors. Surgery: Lip repositioning for hypermobile lip; orthognathic surgery (Le Fort I impaction) for VME. Dentist: Final restorations after tissue/bone is stable. 11 |
| “Black Triangles” (Open Gingival Embrasures) | Loss of interdental papilla height. |
|
Restorations (Veneers/Bonding): Close the space by making contacts longer and more apical. Limitation: Can lead to very long, unesthetic contact areas and poor tooth proportions; difficult to clean. | Ortho: Root paralleling/re-approximation to create a more favourable emergence profile for the papilla. Perio: Papilla regeneration techniques (experimental). Dentist: Design restorations with appropriate contact position after orthodontic repositioning. 16 |
| Severe Wear with Loss of VDO | Pathologic tooth wear, reduced facial height. |
|
Full Mouth Crowns: Restore tooth form and function. Limitation: Without a systematic approach to VDO, the new restorations may fail, impinge on phonetic space, or cause muscle/TMJ issues. Simply “making teeth longer” is not a plan. | Dentist: Lead the case. Use DSD and diagnostic wax-up to plan new VDO and occlusal scheme. All Specialties: Full-mouth rehabilitation may require endodontics for worn teeth, periodontics for crown lengthening, and orthodontics to improve alignment before restoration. 11 |
| Peg Laterals with Diastema | Congenitally small/conical lateral incisors with spacing. | Genetic anomaly. | Direct Bonding or Veneer on Lateral: Build up the tooth to fill the space. Limitation: Often results in a single, disproportionately wide lateral incisor that violates aesthetic proportions, while the central and canine remain unchanged. | Ortho: Redistribute anterior spaces to create ideal mesiodistal width for the lateral incisor restoration and to idealize space for centrals/canines. Dentist: After orthodontics, restore the peg lateral with a veneer or crown to the pre-planned, ideal dimensions. 49 |
| Canted Occlusal Plane | Asymmetry of the incisal/occlusal plane relative to the interpupillary line. |
|
Asymmetric Restorations: Attempt to create the illusion of a level plane by asymmetrically preparing teeth and altering incisal lengths. Limitation: Major aesthetic compromise, often looks unnatural and still imbalanced. | Ortho: Primary treatment—use mechanics (e.g., TADs) to intrude one side and/or extrude the other to level the occlusal plane. Surgery: In severe skeletal cants, orthognathic surgery may be required. Dentist: Final, symmetrical restorations after foundational plane correction. 18 |
Works Cited
1. Alt, K. W., & Türp, J. C. (1998). Cosmetic Dentistry in Ancient Times: A Short Review. International Journal of Periodontics & Restorative Dentistry, 18(6), 587–593.
2. Wikipedia contributors. (2025, August). History of dental treatments. In Wikipedia. Retrieved August 30, 2025, from Wikipedia: History of dental treatments.
3. Gwinnett, A. J., & Gorelick, L. (1979). Ancient Egyptian dentistry. Bulletin of the History of Dentistry, 27(2), 77-83.
5. McLaren, E. A., & Culp, L. (2013). Smile analysis and esthetic design: The new horizontal and vertical parameters. Dental supplement to Spear Education, 1-10.
10. Snow, S. R. (1999). Esthetic smile analysis of maxillary anterior tooth width: the golden percentage. Journal of Esthetic Dentistry, 11(4), 177-184.
11. Magne, P., & Belser, U. (2002). Bonded porcelain restorations in the anterior dentition: A biomimetic approach. Quintessence Publishing.
12. Sarver, D. M. (2001). The importance of incisor positioning in the esthetic smile: the smile arc. American Journal of Orthodontics and Dentofacial Orthopedics, 120(2), 98-111.
14. Rufenacht, C. R. (1990). Fundamentals of esthetics. Quintessence Publishing.
15. Levin, E. I. (1978). Dental esthetics and the golden proportion. The Journal of Prosthetic Dentistry, 40(3), 244-252.
16. Fradeani, M. (2004). Esthetic analysis: A systematic approach to prosthetic treatment. Volume 1. Quintessence Publishing.
17. Tjan, A. H., Miller, G. D., & The, J. G. (1984). Some esthetic factors in a smile. The Journal of Prosthetic Dentistry, 51(1), 24-28.
18. Spear, F. M. (2006). The esthetic management of worn anterior teeth. Compendium of Continuing Education in Dentistry, 27(3), 150-159.
19. Al-Johany, S. S., Alqahtani, A. S., Al-Zordk, D. M., & Al-Otaibi, M. N. (2018). Perception of buccal corridors in smile esthetics among saudi dental students and laypersons. The Journal of Contemporary Dental Practice, 19(6), 696-701.
20. Coachman, C., Calamita, M., & Sesma, N. (2017). Dynamic documentation of the smile and the 2D/3D digital smile design process. The International Journal of Periodontics & Restorative Dentistry, 37(2), 183-193.
22. Profitt, W. R., White, R. P., & Sarver, D. M. (2003). Contemporary treatment of dentofacial deformity. Mosby.
23. Krishnan, V., Daniel, S. T., Lazar, D., & Asok, A. (2008). Characterization of posed smile by quantitative video analysis. American Journal of Orthodontics and Dentofacial Orthopedics, 133(4), 542-e1.
24. Geron, S., & Atalia, W. (2005). Influence of sex on the perception of oral and smile esthetics with different gingival display and incisal plane inclination. The Angle Orthodontist, 75(5), 778-784.
25. Alhammadi, M. S., Halboub, E., Al-Akwa, A. A., & Al-Mashraqi, A. A. (2024). Smile line attractiveness as perceived by university students: A comparative cross-sectional study. Journal of Oral and Maxillofacial Surgery, Medicine, and Pathology, 36(1), 17-22.
26. Liang, T., Zhao, Z., & Ding, Y. (2023). Perception of smile esthetics among orthodontists, general dentists, and laypeople in China. Journal of Dental Sciences, 18(1), 246-253.
28. Vig, R. G., & Brundo, G. C. (1978). The kinetics of anterior tooth display. The Journal of Prosthetic Dentistry, 39(5), 502-504.
29. Zadeh, H. H. (2011). Periodontal plastic and esthetic surgery. Periodontology 2000, 57(1), 7-10.
30. Al-Marzok, M. I., Drees, B. B., & Al-Adwani, S. H. (2013). The golden proportion in the Saudi Arabian population. The Journal of Contemporary Dental Practice, 14(4), 712-717.
33. Guess, P. C., Schultheis, S., Bonfante, E. A., Coelho, P. G., Ferencz, J. L., & Silva, N. R. (2013). All-ceramic systems: laboratory and clinical performance. Dental Clinics of North America, 57(2), 269-286.
38. Etcoff, N. (1999). Survival of the prettiest: The science of beauty. Doubleday.
39. Vanini, L. (1996). Light and color in anterior composite restorations. Practical Periodontics and Aesthetic Dentistry, 8(7), 673-682.
40. Munsell, A. H. (1905). A Color Notation. Geo. H. Ellis Co.
41. VITA Zahnfabrik. (2019). VITA classical A1-D4 shade guide product information.
42. Chu, S. J., Devigus, A., Mieleszko, A. J., & Valenti, M. (2004). Fundamentals of color: Shade matching and communication in esthetic dentistry. Quintessence Publishing.
43. ten Bosch, J. J., & Coops, J. C. (1995). Tooth color and reflectance as related to light scattering and enamel hardness. The Journal of Dental Research, 74(1), 374-380.
45. Edelhoff, D., & Sorensen, J. A. (2002). Tooth structure removal associated with various preparation designs for anterior teeth. Journal of Prosthetic Dentistry, 87(5), 503-509.
46. Amsterdam, M. (1974). Periodontal prosthesis. Twenty-five years in retrospect. Alpha Omegan, 67(3), 8-52.
47. Turner, K. A., & Missirlian, D. M. (1984). Restoration of the extremely worn dentition. The Journal of Prosthetic Dentistry, 52(4), 467-474.
48. Mizumoto, Y., & Baba, K. (2020). Digital smile design and space management using a virtual 3D setup model in a patient with severe tooth wear. The Journal of Prosthetic Dentistry, 123(1), 1-6.
49. Kokich, V. O. (2002). Maxillary lateral incisor implants: a dilemma. Seminars in Orthodontics, 8(2), 121-129.
50. Garber, D. A., & Salama, M. A. (1996). The aesthetic smile: diagnosis and treatment. Periodontology 2000, 11(1), 18-28.
51. Beier, U. S., Kapferer, I., & Dumfahrt, H. (2012). Clinical long-term evaluation and failure characteristics of 1,335 all-ceramic restorations. The International Journal of Prosthodontics, 25(1), 70-78.
52. Mladenović, S., Mladenović, D., Dodić, S., & Stanković, S. (2018). Patient-centered approach in modern aesthetic dentistry. Vojnosanitetski Pregled, 75(5), 512-518.
53. Ong, L. M., de Haes, J. C., Hoos, A. M., & Lammes, F. B. (1995). Doctor-patient communication: a review of the literature. Social Science & Medicine, 40(7), 903-918.
55. Goldstein, R. E. (2007). Esthetics in dentistry (Vol. 1). BC Decker.
56. Coachman, C., & Calamita, M. A. (2012). Digital smile design: a tool for treatment planning and communication in esthetic dentistry. Quintessence of Dental Technology, 103-112.
57. Jafari, T., & Coachman, C. (2018). The influence of digital smile design on patient satisfaction. Journal of Cosmetic Dentistry, 34(2), 52-59.
59. Gürel, G. (2003). The science and art of porcelain laminate veneers. Quintessence publishing.
63. Morley, J., & Eubank, J. (2001). Macroesthetic elements of smile design. The Journal of the American Dental Association, 132(1), 39-45.
65. Samorodnitzky-Naveh, G. R., Geiger, S. B., & Levin, L. (2007). Patients' satisfaction with dental esthetics. The Journal of the American Dental Association, 138(6), 805-808.
67. Fardouly, J., & Vartanian, L. R. (2016). Social media and body image concerns: A review and meta-analysis. Body Image, 19, 1-12.
74. Shillingburg, H. T., Hobo, S., Whitsett, L. D., Jacobi, R., & Brackett, S. E. (2012). Fundamentals of fixed prosthodontics. Quintessence Publishing.
76. Blatz, M. B., Sadan, A., & Kern, M. (2003). Resin-ceramic bonding: a review of the literature. The Journal of Prosthetic Dentistry, 89(3), 268-274.