Dental professionals have long been guided by mathematical principles when inter- preting aesthetic and tooth proportions for their patients. While many acknowl- edge that such principles are merely launch points for a smile design or reconstructive procedure, their existence appears to indicate practitioners’ desire for predictable, objective, and reproducible means of achieving success in aesthetic dentistry. This article introduces innovative aesthetic measurement gauges as a means of objec- tively quantifying tooth size discrepancies and enabling the clinician to perform aesthetic restorative dentistry with success and predictability.
Learning Objectives:
This article discusses an approach for predictable diagnosis and correction of discrepancies in tooth size and individual tooth proportion. Upon reading this article, the reader should:
• Be able to quantatively evaluate aesthetic tooth dimensions.
• Recognize the benefits of measurement gauges in the development of proper individual tooth size
This article discusses an approach for predictable diagnosis and correction of discrepancies in tooth size and individual tooth proportion. Upon reading this article, the reader should:
• Be able to quantatively evaluate aesthetic tooth dimensions.
• Recognize the benefits of measurement gauges in the development of proper individual tooth size
Dental professionals have long been guided by mathematical principles when interpreting aesthetic and tooth proportions for their patients. While many acknowledge that such principles are merely launch points for a smile design or reconstructive procedure, their very existence appears to indicate practitioners’ desire for some predictable, objective, and reproducible means of achieving success in aesthetic dentistry
The clinical reality, however, is that intra-arch tooth relationships used as guidelines for smile designs (eg, the Golden Proportion) are applicable to a confined seg- ment of the patient population. In addition, dentists have been found to be less pleased with aesthetic outcomes with smiles designed using the Golden Proportion,2 and patients have been found to dislike such a proportion rela- tionship. Therefore the only tangible parameter in aesthetic dentistry is individual tooth size and proportion.
Individual tooth size can be thought of as the build- ing blocks of a smile design. Once the tooth size and pro- portion of the maxillary anterior teeth are corrected, they can then be arranged within the dental arch. Intra-arch tooth relationship proportions such as the recurring aesthetic den- tal proportion, which has been found to be amenable to patients and clinicians, can be used to arrange the teeth for a pleasing smile. This task is simplified in removable prosthodontics, in which selection of the proper tooth size and form is the primary step before their arrangement within the dental arch or tooth setup. With the natural dentition, this task is infinitely more difficult, since the dilemma is such that existing teeth may exhibit altered width and/or length discrepancies due to developmental anomalies, changes resulting from the aging process, or prior restora- tive procedures. Therefore, correction may require combi- nation therapies such as orthodontics and/or periodontics prior to aesthetic restorative dentistry.
In daily practice, the clinician’s use of “nonstandard” proportions to treat teeth with abnormal size relative to accepted width and height values can yield narrow or square teeth that are unnatural in size and shape and fail to achieve the aesthetic expectations of either the patient or clinician. This can be particularly challenging when per- formed with visual assessment only (ie, absent of clinical tools). Standardized individual tooth size and proportions fall within a given range around mean values, however, and gender differences exist between anterior tooth groups. Therefore, these parameters can be used to pre- dictably diagnosis and correct discrepancies in tooth size and individual tooth proportion.
Historical Background
Traditionally, dental instruments (eg, explorers, probes) have been used as reference standards to detect diseases such as caries and periodontitis. Periodontitis is detected, evaluated, and assessed using numerical val- ues indicative of health or stage of disease. Instrumentation does not exist, however, to address aesthetic deformities from diagnosis to correction
Aesthetic tooth dimensions can be evaluated and treated by similar numerical analysis. To test the appli- cation of these concepts, the author created prototype instruments. Metal wire (ie, 0.036 gauge) was sol- dered to form a Siamese twin instrument tip with pre- set markings notched into the surface with measurements indicating a 78% width (W) to length (L), proportion (Figure 1). Once the incisal edge position was established, the width of a tooth could be measured with the prototype instrument, and the notch on the short arm noted; then the corresponding notch on the long arm could be marked as the reference point for the new clinical crown length at a preset W/L ratio (Figures 2 through 4).
Revolutionary Instrumentation
Aesthetic measurement gauges (ie, Chu’s Aesthetic Gauges, Hu-Friedy Inc, Chicago, IL), designed for diagnosis and correction of tooth size discrepancies and deformities, have been developed to eliminate the subjectivity associated with restorative care. These measurement tips include the Proportion Gauge (PG), which represents an objective mathematical appraisal of tooth size ranges. Through the use of such instrumentation, the clinician has a clearly visible means of applying aesthetic values to a patient chairside, directly or indirectly in the laboratory during projected treatment planning, and to objectively determine the intended treatment outcome.
The PG is designed as a double-ended instrument (ie, gauge) with a T-Bar and In-Line tip screwed into the handle at opposing ends. The T-Bar tip features an incisal edge position (ie, incisal stop); when a tooth is oriented with the tip accordingly, the practitioner can accurately evaluate its length (ie, vertical arm) and width (ie, hori- zontal arm) dimensions simultaneously. The width is indi- cated in equidistant 0.5-mm increments bilaterally, each with a vertical mark in a corresponding color (Figure 5). Thus, a central incisor with a “red” width of 8.5 mm will be in proper proportion if its height is also the “red” height (ie, 11 mm).
The In-Line tip is analogous to the metal prototype used in the aforementioned case study; the most significant difference being that the latter is a color-coded, plastic, disposable unit. The utility of the In-line gauge is identical to the T-Bar tip, except for the fact that the horizontal arm of the T-Bar is now the short arm of the In-Line tip; the vertical arm and long arm of the tips are also the same. The short arm, at 1-mm increments, mea- sures the tooth width, and the long arm measures the corresponding length at alternating 1.5-mm/1-mm incre- ments, since the gauge is mathematically set at 78% W/L proportion. The black line at the base of the tip denotes the incisal guide, which is the starting point of measurement (Figure 6).
Should crown lengthening be necessary to achieve this result, the alternating 1.5-mm/1-mm increments marked on the vertical axis of the gauge yield predictable requirements for the increased vertical height of the gin- gival architecture complex.
Utility .
These gauges enable clinicians to diagnosis and cor- rect tooth size discrepancies. The present armamen- tarium for such diagnosis consists of manual and digital calipers, Bouley gauges, millimeter rulers, and peri- odontal probes. The gauges are designed to replace the present techniques, allowing simple diagnosis of tooth width and/or length problems as well as gingi- val length discrepancies
In daily practice, the clinician’s use of “nonstandard” proportions to treat teeth with abnormal size relative to accepted width and height values can yield narrow or square teeth that are unnatural in size and shape and fail to achieve the aesthetic expectations of either the patient or clinician. This can be particularly challenging when per- formed with visual assessment only (ie, absent of clinical tools). Standardized individual tooth size and proportions fall within a given range around mean values, however, and gender differences exist between anterior tooth groups. Therefore, these parameters can be used to pre- dictably diagnosis and correct discrepancies in tooth size and individual tooth proportion.
Historical Background
Traditionally, dental instruments (eg, explorers, probes) have been used as reference standards to detect diseases such as caries and periodontitis. Periodontitis is detected, evaluated, and assessed using numerical val- ues indicative of health or stage of disease. Instrumentation does not exist, however, to address aesthetic deformities from diagnosis to correction
Aesthetic tooth dimensions can be evaluated and treated by similar numerical analysis. To test the appli- cation of these concepts, the author created prototype instruments. Metal wire (ie, 0.036 gauge) was sol- dered to form a Siamese twin instrument tip with pre- set markings notched into the surface with measurements indicating a 78% width (W) to length (L), proportion (Figure 1). Once the incisal edge position was established, the width of a tooth could be measured with the prototype instrument, and the notch on the short arm noted; then the corresponding notch on the long arm could be marked as the reference point for the new clinical crown length at a preset W/L ratio (Figures 2 through 4).
Revolutionary Instrumentation
Aesthetic measurement gauges (ie, Chu’s Aesthetic Gauges, Hu-Friedy Inc, Chicago, IL), designed for diagnosis and correction of tooth size discrepancies and deformities, have been developed to eliminate the subjectivity associated with restorative care. These measurement tips include the Proportion Gauge (PG), which represents an objective mathematical appraisal of tooth size ranges. Through the use of such instrumentation, the clinician has a clearly visible means of applying aesthetic values to a patient chairside, directly or indirectly in the laboratory during projected treatment planning, and to objectively determine the intended treatment outcome.
The PG is designed as a double-ended instrument (ie, gauge) with a T-Bar and In-Line tip screwed into the handle at opposing ends. The T-Bar tip features an incisal edge position (ie, incisal stop); when a tooth is oriented with the tip accordingly, the practitioner can accurately evaluate its length (ie, vertical arm) and width (ie, hori- zontal arm) dimensions simultaneously. The width is indi- cated in equidistant 0.5-mm increments bilaterally, each with a vertical mark in a corresponding color (Figure 5). Thus, a central incisor with a “red” width of 8.5 mm will be in proper proportion if its height is also the “red” height (ie, 11 mm).
The In-Line tip is analogous to the metal prototype used in the aforementioned case study; the most significant difference being that the latter is a color-coded, plastic, disposable unit. The utility of the In-line gauge is identical to the T-Bar tip, except for the fact that the horizontal arm of the T-Bar is now the short arm of the In-Line tip; the vertical arm and long arm of the tips are also the same. The short arm, at 1-mm increments, mea- sures the tooth width, and the long arm measures the corresponding length at alternating 1.5-mm/1-mm incre- ments, since the gauge is mathematically set at 78% W/L proportion. The black line at the base of the tip denotes the incisal guide, which is the starting point of measurement (Figure 6).
Should crown lengthening be necessary to achieve this result, the alternating 1.5-mm/1-mm increments marked on the vertical axis of the gauge yield predictable requirements for the increased vertical height of the gin- gival architecture complex.
Utility .
These gauges enable clinicians to diagnosis and cor- rect tooth size discrepancies. The present armamen- tarium for such diagnosis consists of manual and digital calipers, Bouley gauges, millimeter rulers, and peri- odontal probes. The gauges are designed to replace the present techniques, allowing simple diagnosis of tooth width and/or length problems as well as gingi- val length discrepancies
The color-coded marks on the horizontal axis (ie, width portion) of the T-bar tip are aligned to the corresponding color markings on the vertical axis (ie, length portion) of the instrument. The numbers on the horizontal axis are organized from inside (ie, 5.5 mm) to outside (ie, 10.5 mm) in 1-mm bilateral increments (Figure 5). The numbers on the vertical axis are orga- nized from bottom (ie, 7 mm) to the top (ie, 13.5 mm). The most common width/length numbers for the lateral (ie, blue), canine (ie, yellow), and central (ie, red) incisors are 6.5/8.5, 7.5/9.5, and 8.5/11 mm, respectively (Figure 7). The incisal edge position must be established before any gauges are used.
The In-Line proportion tool measures the width and length of the lateral, canine and central incisors inde- pendently when crowding is present (Figures 8 and 9). This instrument is color-coded similarly to the T-bar, with a preset width/length ratio of 78% and color-coded marks on the width portion aligned to the correspond- ing color markings on the length portion. The most com- mon width/length numbers for the lateral (ie, blue), canine (ie, yellow), and central (ie, red) incisors are 6.5/8.5, 7.5/9.5, and 8.5/11 mm, respectively. The width is measured first and then the corresponding color-coded length is noted. There is an inci- sal guide to help position and orient the instrument during measurement
The In-Line proportion tool measures the width and length of the lateral, canine and central incisors inde- pendently when crowding is present (Figures 8 and 9). This instrument is color-coded similarly to the T-bar, with a preset width/length ratio of 78% and color-coded marks on the width portion aligned to the correspond- ing color markings on the length portion. The most com- mon width/length numbers for the lateral (ie, blue), canine (ie, yellow), and central (ie, red) incisors are 6.5/8.5, 7.5/9.5, and 8.5/11 mm, respectively. The width is measured first and then the corresponding color-coded length is noted. There is an inci- sal guide to help position and orient the instrument during measurement
Clinical Applications
Tooth size is a critical facet in aesthetics and has clin- ical relevance in restorative dentistry, orthodontics, periodontics, and implant dentistry. This is especially true and pertinent in the more complex restorative space management (RSM) case types, in which orthodontic therapy alone may be inadequate to address all the needs of the patient. These measurement gauges (ie, Chu’s Aesthetic Gauges, Hu-Friedy Inc, Chicago, IL) allow standardization of tooth size parameters as well as objective communication between clinicians and auxiliaries involved in comprehensive patient care from diagnosis (Figure 10), indirect case planning (Figures 11 and 12), treatment provisional restora- tions, and verification of tooth size correction to the final aesthetic restorative outcome (Figures 13 through 16).
Orthodontic therapy involves managing space discrepancies such as excessive or insufficient space due to tooth size and/or arch size discrepancies. Frequently, residual spaces are purposely fashioned to allow the restorative dentist to create the proper tooth size and form. Conversely, excessive space and/or tooth stucture can be condensed to provide the cor- rect tooth size and proportion. Having measurement gauges that can guide the clinician in these RSM case types can lend to not only a stable occlusion, but also an aesthetically pleasing smile (Figures 17 through 24).
Aesthetic periodontal therapy demands addition and/or subtraction procedures in an effort to restore the proper tooth size and form. These gauges facilitate easy and quick diagnosis for addition (eg, grafting) or sub- traction (eg, crown reduction) procedures to correct tooth size discrepancies.
Lastly, implant dentistry not only requires osseointegration for successful tooth replacement, but also edentulous ridge augmentation in order to provide enough hard and/or soft tissue to allow the proper tooth size to be established in the final aesthetic restorative outcome.
Conclusion
Human dental anatomy has not changed significantly in hundreds of years. Although dental and dental lab- oratory students are taught human dental anatomy and morphology in preclinical curriculum, practitioners often see dental restorations that do not exhibit the proper proportions of natural teeth. When visually essential aspects of dental anatomy and composition are not accurately incorporated into aesthetic restorations, patients are not completely served and practitioners may be frustrated as well.
The clinical examples depicted herein demonstrate the applicability of an aesthetic gauge system in maintaining anterior aesthetics for both standard and non-standard tooth sizes. When the tooth dimensions are maintained at 8.5 mm and 11 mm, a standardized length-to-width ratio can be developed. The aesthetic gauge can, however, be easily applied to non-standard tooth lengths (as demonstrated in the final clinical case), allowing the clinician to develop a harmonious pro- portion even when treating teeth with longer clinical crown lengths or widths. It is, therefore, the maintenance of biometric proportions that will influence overall tooth harmony, particularly when treating teeth that fall outside of the traditional guidelines. The creation and use of instruments such as these not only allows the restorative dentist to be an artist, giving expression to the restoration itself, but also provides the clinician with the opportunity to become an architect, incorporating numerical values of anatomic tooth dimensions and proportions into aesthetically pleasing smile makeovers. Thus, the new generation of aesthetic dentists will be architects and artists of the dentition.
Human dental anatomy has not changed significantly in hundreds of years. Although dental and dental lab- oratory students are taught human dental anatomy and morphology in preclinical curriculum, practitioners often see dental restorations that do not exhibit the proper proportions of natural teeth. When visually essential aspects of dental anatomy and composition are not accurately incorporated into aesthetic restorations, patients are not completely served and practitioners may be frustrated as well.
The clinical examples depicted herein demonstrate the applicability of an aesthetic gauge system in maintaining anterior aesthetics for both standard and non-standard tooth sizes. When the tooth dimensions are maintained at 8.5 mm and 11 mm, a standardized length-to-width ratio can be developed. The aesthetic gauge can, however, be easily applied to non-standard tooth lengths (as demonstrated in the final clinical case), allowing the clinician to develop a harmonious pro- portion even when treating teeth with longer clinical crown lengths or widths. It is, therefore, the maintenance of biometric proportions that will influence overall tooth harmony, particularly when treating teeth that fall outside of the traditional guidelines. The creation and use of instruments such as these not only allows the restorative dentist to be an artist, giving expression to the restoration itself, but also provides the clinician with the opportunity to become an architect, incorporating numerical values of anatomic tooth dimensions and proportions into aesthetically pleasing smile makeovers. Thus, the new generation of aesthetic dentists will be architects and artists of the dentition.
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