Incisal Edge Position Research Articles

The 3D-printed shell complete denture technique: Simplifying prosthodontic diagnosis prior to implant planning.

Traditionally, artificial teeth arrangements or the definitive complete dentures are used to establish important prosthodontic parameters such as the occlusal plane orientation, vertical dimension, and the incisal edge position. The relationship of these elements with the underlying bony structures is commonly evaluated using advanced planning protocols such as the dual scan technique. This technique article presents an uncomplicated alternative approach to establish these parameters intraorally using a 3D-printed shell complete denture generated from a 3D scan of the patient's existing complete denture.

Digital workflow to produce 3D-printed incisal facial indirect restoration with lingual rest seats to support a removable partial denture

A technique for fabricating lingual rest seats and indirect incisal restorations using a digital workflow is described. After intraoral scanning, the incisal edge position of the restoration and lingual rest seats for a subsequent removable partial denture (RPD) were designed digitally. Adaptation was evaluated with trial restorations, and definitive restorations were printed from a 3-dimensional resin (Varseo Smile Crown Plus Bego; Wilcos). The restorations were cemented with a heated composite resin (Tetric N; Ivoclar AG) polymerized for 40 seconds. The RPD was fabricated and delivered following a conventional technique. This standard, rapid, cost-effective, and straightforward approach allows a controlled and standardized process to obtain lingual rest seats and incisal restorations simultaneously, providing support for a successful Kennedy Class I RPD.

TO CORRELATE THE RELATIONSHIP OF THE DISTANCE BETWEEN LINGUAL FRENAL ATTACHMENT AND MANDIBULAR INCISAL EDGE POSITION AS AN AID IN ESTABLISHING MANDIBULAR OCCLUSAL PLANE: A CROSS-SECTIONAL SURVEY

Background: The determination of vertical dimension, aesthetics, phonetics and incisal guidance, depends on the placement of anterior teeth. Fewer studies are present for mandibular anterior teeth setting. Therefore this study aims at determining the correlation of distance between lingual frenal attachment and mandibular incisal edge position in dentulous subjects as an aid in establishing mandibular occlusal plane in edentulous patients. Methodology: 318 subjects (161 males and 157 females) under the age group of 18 to 30 years, who met the requisite criteria were seleceted. A mandibular cast was obtained from irreversible hydrocolloid impression in stock trays for each subject. The distance between the incisal edge of lower central incisor and anterior attachment of the lingual frenum was measured using digital vernier caliper. Result:It was observed that the distance between anterosuperior attachment of lingual frenumand mesioincisal edge of mandibular central incisor (CI) in female subjects was 12.19, with mean standard deviation (±SD) of 1.34. and 15.91 with mean standard deviation (±SD) 1.32 in male subjects respectively. Conclusion:Thus, the anterior attachment of lingual frenum is a reliable anatomic landmark and shall aid in setting the mandibular central incisors in a more natural position.

Analysis of the distance between lingual frenal attachment and mandibular incisal edge position in establishing occlusal plane in three different races.

The orientation of the occlusal plane forms the basis for the arrangement of teeth conducive to satisfactory esthetics and function, making it one of the most important clinical procedures in prosthodontic rehabilitation. This study aimed to analyze and compare the vertical distance between the anterior attachment of lingual frenum (AALF) and the incisal edge of mandibular central incisors among three races in Malaysia. The sample consisted of 63 dentate subjects (21 Malays, 21 Chinese, and 21 Indians) who were chosen based on the inclusion criteria. Two models were made using irreversible hydrocolloid impressions, and an average of the value was obtained. Lingual frenum was recorded in function. Casts were fabricated with dental stone. AALF was marked and the vertical distance was measured using a caliper. In Malays, the mean and standard deviation of the vertical distance were 14.2 ± 0.9 mm, with a range of 12.3-16.0 mm; in Chinese were 14.4 ± 0.9 mm, with a range of 12.0-16.9 mm; and in Indians were 15.1 ± 1.0 mm, with a range of 13.0-17.2 mm. The difference among the three races regarding the distance between AALF and the incisal edge of mandibular central incisors was statistically significant (P < 0.05). Among the three races, Malays and Indians have the greatest mean difference. According to the results of the current study, the distance between AALF and the incisal edge of mandibular central incisors might be a proper criterion for the initial adjustment of occlusal rims. The values obtained from three different races were significantly different from one another, hence a different range of values was used to establish occlusal height for different races.

Accuracy of anterior denture tooth arrangements of CAD-CAM complete removable dental prostheses made with a tooth mold template

Statement of problemResearch evaluating the accuracy of anterior tooth mold templates to computer-aided design and computer-aided manufacture (CAD-CAM) fabricated complete removable dental prostheses (CRDPs) is limited. PurposeThe purpose of this in vitro study was to investigate the accuracy of the anterior denture tooth arrangement on CAD-CAM complete removable dental prostheses made with the anterior tooth mold template. Material and methodsA maxillary and mandibular edentulous model was mounted on a semiadjustable articulator to simulate a patient’s maxillary arch. Definitive impressions and jaw relation records were made as per the manufacturer’s protocol. A maxillary and mandibular anatomic measuring device was completely seated onto the edentulous models, centered on the edentulous model midline, and horizontally positioned parallel to the mandibular ridge. A medium-size anterior tooth mold template sticker was attached on the anatomic measuring device to identify the maxillary dental midline and incisal edge position and was sent to the manufacturer as the proposed tooth arrangement reference for the definitive complete removable dental prostheses. A total of 10 milled complete removable dental prostheses were generated for 2 groups by using 2 different tooth arrangement techniques. One group (n=5) used the monobloc milling technique without bonding of denture teeth, while the other group (n=5) used the bonding system for denture teeth on the milled denture base. For comparison, a camera mounted on a tripod was used for photographic documentation. Reference markers placed on the edentulous model were used to orient and measure the difference of 4 aspects of the anterior tooth arrangement: average incisal edge position, intercanine distance, midline, and clinical crown length of the left central incisor. The difference values between the tooth mold template and definitive complete removable dental prostheses were statistically analyzed by multivariate ANOVA (α=.05) and 1-sample t tests (adjusted α=.0125). ResultsOverall, statistically significant differences were found between the tooth mold template (control) and definitive complete removable dental prostheses at all measuring aspects except for the midline of the midline of the milled arrangement technique (P<.0125). In terms of the midline value, the value of the milled group did not show a significant difference compared with tooth mold template (-0.19 mm). However, the value of the bonded group indicated a significant difference of midline (0.44 mm toward to the left of the tooth mold template midline). When the complete removable dental prosthesis milled denture tooth and complete removable dental prosthesis bonded denture tooth techniques were compared, there was no difference in the tested variables between the milled and the bonded groups (P>.0125). ConclusionsThe tooth mold template did not represent an accurate position for definitive complete removable dental prostheses for either the milled or bonded techniques. The largest differences were found at the average incisal edge of the anterior teeth and the intercanine distance for both groups. However, there was overall no clinical difference between the 2 groups (milled and bonded) of CAD-CAM complete removable dental prostheses.

Rehabilitating simulated worn dentition by using a complete digital workflow and five anatomic guidelines

This report describes the rehabilitation of worn dentition by using a complete digital workflow on a nonhinged simulated patient. A dentiform was used to represent an individual with loss of occlusal vertical dimension. Interim restorations were designed following the simulated patient's midline, interpupillary line, and ala-tragus line and a defined central incisal edge position, posterior maxillary teeth central groove, and buccal cusp position of posterior maxillary teeth. The definitive restorations were then designed and fabricated by following the contour of the interim restorations.

Periodontal plastic surgery for the management of an ankylosed permanent maxillary lateral incisor: A clinical report with 5-year follow-up

Anterior maxillary tooth ankylosis disturbs the development of the alveolar bone process, leading to discrepancies between the cervical gingival margin and incisal edge position of the affected tooth, and therefore, the esthetics is compromised. Proposed treatments in adults and growing patients have been used successfully, but they have disadvantages and are contraindicated in some circumstances. This article proposes an alternative treatment for an ankylosed permanent maxillary anterior tooth with a slow replacement resorption rate in an adult patient, for whom a combination of a periodontal plastic surgery procedure and a fixed dental prosthesis was used to correct the esthetics. This treatment has less risk of complications, preserves the ankylosed tooth as long as possible, creates an optimal gingival contour, and maintains the alveolar bone for further treatment should the tooth be lost.

Comparison of Two Different Intrusion Techniques (An in Vitro Study)

Aims: This study was aimed to compare the effects of two different techniques on the position of maxillary incisors during the intrusive movement. Materials and Methods: The sample consisted of two groups, the utility intrusion arch and continuous intrusion arch groups. Upper typodont arch of class II division I was used and the arches were activated to deliver 60 gram of force. Pre and postoperative digital images were taken and analyzed using Autodesk AutoCAD software™. For each group six parameters were measured and compared. A significance value of 0.05 was predetermined. Results: Significant difference was found in vertical change of estimated midpoint of root position, axial inclination, anteroposterior position of incisal edge, relative contribution of torque and protrusion to the change in inclination and insignificant difference in vertical change of incisal edge position. Conclusions: Maxillary incisors intrusion with a minimal protrusion could be achieved with the continuous intrusion arch technique

Smile Aesthetics among Late Adolescents: Perspective of Adolescents, General Dentists and Orthodontists

Introduction: An adolescent’s personal experiences, peer influences and social environment can affect their preference towards smile aesthetics and have influence apart from the opinion of their orthodontists. Aim: To evaluate and compare the preferences regarding smile arc, gingival display, midline symmetry, shape and size of incisor teeth, buccal corridor space and smile index of adolescent subjects between late adolescents, general dentists and orthodontists. Materials and Methods: A total of 52 orthodontists, 111 general dentists and 275 adolescents (156 females, 119 males) had participated in this cross-sectional study from 1st September 2019 to 31st January 2020. Each participant was shown a photo album consisting of 5 sets of photographs of male and female adolescent subjects and was asked to rate them on 7 selected variables. The data obtained was subjected to comparison between the groups using Chi-square test. Results: While assessing smile of the female subject, other than the incisal edge position, the intergroup comparisons of gingival display (p=0.0001), midline symmetry (p=0.0001), shape of incisor teeth (p-value=0.0001), buccal corridor space (p=0.001), ratio of central: lateral incisor (p=0.016) and smile index (p=0.0001) were statistically significant. While assessing smile of the male subject, the intergroup comparisons of incisal edge position (p=0.0001), gingival display (p=0.001), midline symmetry (p=0.007), shape of incisor teeth (p-value=0.0001), buccal corridor space (p=0.0001), ratio of central: lateral incisor (p=0.0001) and smile index (p=0.0001) were statistically significant. Orthodontists’ accepted gingival display of 0-2 mm, midline deviation up to 2 mm and buccal corridor space of upto 5 mm and upto 25% increase in smile index in both genders. Conclusion: The Orthodontists and dentists have more similarities than differences in comparison to adolescents with respect to the smile preferences of adolescent subjects.

Esthetic Crown Lengthening with Flapless Osseous Reduction using Abrasive Bur: A New Innovative Approach

Introduction: A smile design were evaluation and analysis of both facial and dental composition. Facial driven principle like basic shape of face, incisal edge position, tooth components and gingival levels were key factor to achieving pleasing smile. In crown lengthening with open flap procedure, black triangle was the most common complication. But in some indications, it is possible to do osseous reduction in flapless approach. Objectives: Facial driven measurement protocol and flapless osteotomy in crown lengthening will result more predictable and less risk of black triangle. This new approach provide more user friendly for clinician. Case management: Patient come in a private practice clinic for smile esthetic complain. Face profile were long straight, insisal edge position on smiling showing more than 2.0 mm gingival expose, F and V test were added to determine labiolingual position. Teeth’s proportion and gingival level using Chu guiding system. Sulcus and bone sounding were measured. Gummy smile and osseous reduction crown lengthening was indicated. Flapless osteotomy procedure performs to prevent black triangle. This approach where gently elevate marginal gingival through alveolar crest with gingival retractor after gingivoplasty without interfere its papilla and then perform osteotomy using small round bur until reach ideal dento-gingival complex. Conclusion: Among the benefits of this protocol were more accurate, low morbidity with no sutures, less bleeding and greater patient acceptance. The outcomes are fair result. Flapless osteotomy in Esthethic crown lengthening is one alternative minimally invasive approach which, when indicated, offers realistic clinical benefits to patients.

Perception of smile esthetics by laypeople of different ages

BackgroundAge is a factor affecting smile esthetics. Three variables of smile esthetics associated with the maxillary anterior teeth and age-related changes have recently received considerable attention: (i) the incisal edge position of the maxillary central incisors, (ii) the maxillary gingival display, and (iii) the presence of a black triangle between the maxillary central incisors. The aim of this study was to evaluate the influence of age on smile esthetic perception based on these three variables in a group of Thai laypeople.MethodsThe smiles were constructed from a photograph of a female smile. Smile photographs were altered in various increments using three variables: the incisal edge position of the maxillary incisors, gingival display, and a black triangle between the maxillary central incisors. The photographs were shown to a group of 240 Thai laypeople. The subjects were divided into two groups: a younger group, 15–29 years old (n = 120) and an older group, 36–52 years old (n = 120). Each subject was asked to score the attractiveness of each smile separately using a visual analog scale.ResultsSmile attractiveness scores concerning the incisal edge positions of the maxillary central incisors were similar between the two groups. However, upper lip coverage was rated as unattractive by the younger group. A gingival display of 0 and 2 mm was rated as most attractive by the younger group. Upper lip coverage and gingival display of 0 and 2 mm were considered attractive by the older group. Excessive gingival display (6 mm) was scored as unattractive by both groups. A black triangle ranging from 1 to 2.5 mm between the maxillary central incisors was scored differently between the two groups. The older group was more tolerant of the black triangle size.ConclusionsAge impacts smile perception based on maxillary gingival display and the presence of a black triangle between the maxillary central incisors, but not of the incisal edge position of the maxillary central incisors. Due to the variation in esthetic perception of each individual, participation between orthodontists and patients for decision-making and treatment planning is a crucial process to provide successful results.

Pronunciation of phonemes in relation to the degree of malocclusion and position of the incisal edges-lip vermilion border

Introduction: Phonetics helps to establish an ideal incisal edge position in relation to the vermilion border during phoneme articulation. Objective: To evaluate the relationship between the incisal edge of the anterior teeth and the vermilion border with the severity of the malocclusion and phonemes articulation of patients attending from January to February 2015 at the Orthodontics Service of Mexico Children’s Hospital «Dr. Federico Gomez». Material and methods: A prospective, observational and cross-sectional study was performed on 40 patients of both genders between the ages of 14 to 25 years old. A digital video sequence was recorded (2 minutes) while the patients pronounced different words. Results: 22.5% of the patients presented phoneme articulation problems (D, K, L, R, S); the phoneme S was found to have the most statistically significant error (8%). Conclusion: It was not observed if a relationship exists between malocclusion severity, incisal edges- vermilion border and phonemes articulation.

Evaluation of the Relationship between Incisal Edge Position of Maxillary Central Incisors and Incisive Papilla in Patients Referred to Prosthodontics Department of Tabriz Dental Faculty

Background and Aims: Teeth position is an important component in a facial esthetic. Distance between incisive papilla and incisal edge of the maxillary centrals is a stable landmark in reconstruction anterior teeth of maxilla. Therefore in this study, we tried to establish this index in patients who recourse to the fixed prosthodontics dentistry faculty of Tabriz. Materials and Methods: The initial samples consisted of 59 patients referred to prosthodontics department of Tabriz dental faculty and took upper jaw impressions with irreversible hydrocolloid. Then, records poured by moldana stone until 15 minutes and needed anatomical spots were highlighted. The horizontal distance from anterior part on incisal edge of the maxillary centrals to anterior border, center and posterior border of incisive papillae were measured and statistically inspected. Results: The mean distance between the most anterior point of the incisal edge of the maxillary central incisors and the middle point, anterior border and posterior border of the incisive papilla was 8.54 ,7.12,10.28 mm with standard deviations of 0.83,0.75,1.002 mm. Conclusions: The usefulness of the incisive papilla as a reference point is limited because of the migration and change of shape it has been shown to undergo. However, it may serve some purpose because it is an easy measurement to make. Although the clinical findings may not always be true, but in many cases there is a close relationship. Key words : Teeth; incisive papilla; maxilla; occlusal plane;

Comparison of the Kois Dento-Facial Analyzer System with an earbow for mounting a maxillary cast

Statement of problemThe Kois Dento-Facial Analyzer System (KDFA) is used by clinicians to mount maxillary casts and evaluate and treat patients. Limited information is available for understanding whether the KDFA should be considered as an alternative to an earbow. PurposeThe purpose of this study was to evaluate maxillary casts mounted using the KDFA with casts mounted using Panadent's Pana-Mount Facebow (PMF). Both articulation methods were compared against a lateral cephalometric radiograph. Material and methodsFifteen dried human skulls were used. Lateral cephalometric radiographs and 2 maxillary impressions were made of each skull. One cast from each skull was mounted on an articulator by means of the KDFA and the other by using the PMF. A standardized photograph of each articulation was made, and the distance from the articular center to the incisal edge position and the occlusal plane angle were measured. The distance from condylar center to the incisal edge and the occlusal plane angle were measured from cephalometric radiographs. Finally, the 3-dimensional position of each articulation was determined with a Panadent CPI-III. A randomized complete block design analysis of variance (RCBD) and post hoc tests (Tukey-Kramer HSD) (α=.05) were used to evaluate the occlusal plane angle and axis-central incisor distance. A paired 2-sample t test for means (α=.05) was used to compare the X, Y, and Z distance at the right and left condyle. ResultsThe KDFA and PMF mounted the maxillary cast in a position that was not statistically different from the skull when comparing the occlusal plane angle (P=.165). Both the KDFA and the PMF located the maxillary central incisor edge position in a significantly different position compared with the skull (P=.001) but were not significantly different from each other. The 3-dimensional location of the maxillary casts varied at the condyles by approximately 9 to 10.3 mm. ConclusionThe KDFA mounted the maxillary cast in a position that was not statistically different from the PMF when comparing the incisal edge position and the occlusal plane angle. Both the KDFA and the PMF located the maxillary incisal edge position in a significantly different position compared with the anatomic position on dried human skulls.

An in-vivo correlation analysis of the distance between lingual frenal attachment and mandibular incisal edge position as an aid in establishing mandibular occlusal plane in South Indian population.

The aim of the study is to find the reliability in measuring the distance between the anterior attachment of the lingual frenum and the incisal edge of the mandibular central incisor on casts to be used as a pre-extraction record. The objective of this study is to give a range of numerical values from anterior attachment of lingual frenum to mandibular central incisors in a class I ridge relation in south Indian population, which may be used in establishing the vertical dimension of the edentulous patient and also to locate the mandibular incisors in teeth arrangement of complete denture fabrication. One hundred subjects (50 males and 50 females) under the age group of 21-28y, with class I dental relationship and who have never undergone orthodontic treatment were selected. Two models were made for each subject using irreversible hydrocolloid impression material and type III gypsum product to obtain an average value for each subject. The distance between the incisal edges of the lower central incisor and the anterior attachment of the lingual frenum is measured using a divider and digital vernier caliper. Mean and Standard deviation using descriptive statistics tool using SPSS software version 18. The distance between the anterior attachment of the lingual frenum and incisal edges of mandibular central incisors among the 100 subjects was 14.50mm ± 2.2245 mm. The value obtained aided in establishing the vertical dimension easier by making a pre-determined height of mandibular occlusal rim.

Occlusal errors generated at the maxillary incisal edge position related to discrepancies in the arbitrary horizontal axis location and to the thickness of the interocclusal record

Determining the arbitrary transverse horizontal axis by using anatomic landmarks is a simpler clinical procedure than locating the kinematic transverse horizontal axis; however, accuracy may vary depending on individual patient anatomy. The purpose of this study was to investigate an arbitrary transverse horizontal axis relative to the maxillary incisal edge and to examine the magnitude of occlusal error produced when this arbitrary transverse horizontal axis is used to mount casts in an articulator. Seventy-three adults (43 men, 30 women) participated in this study. The distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge was measured for each participant. A parametric linear regression was used to analyze the effect of sex on the distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge by using statistical software (SPSS v19.0; SPSS Inc). A linear correlation analysis was used to compare the distance from the arbitrary transverse horizontal axis to the maxillary central incisal edge with the participant's height (α=.05). Four distances from the arbitrary transverse horizontal axis to the maxillary central incisal edge (80, 90, 110, 120mm) and 3 interocclusal record thicknesses (1, 2, 3 mm) were mathematically calculated to examine the magnitude ofocclusal error at the central incisor contact. The mean distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge position was 100.12 (SD 5.33) mm for all participants. Overall, 89.04% of the participants fell within 5 mm of the 100-mm distance. No significant differences in the distance of the arbitrary transverse horizontal axis to the maxillary central incisal edge position were identified between men and women or with the participant's height. The magnitude of occlusal error at the central incisor contact ranged from 0.45 to 11.26 μm. The distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge position was notinfluenced by the sex or height of the participants investigated. Variations in the distance from an arbitrary transverse horizontal axis to the maxillary central incisal edge resulted in minor occlusal discrepancies at the central incisor contact.

Displacement of Screw-Retained Single Crowns into Implants with Conical Internal Connections

Internal conical implant-abutment connections without platforms may lead to axial displacement of crowns during screw tightening. This displacement may affect proximal contacts, incisal edge position, or occlusion. This study aimed to measure the displacement of screw-retained single crowns into an implant in three dimensions during screw tightening by hand or via torque driver. A stereolithic acrylic resin cast was created using computed tomography data from a patient missing the maxillary right central incisor. A 4.0- × 11-mm implant was placed in the edentulous site. Five porcelain-fused-to-metal single crowns were made using "cast-to" abutments. Crowns were tried on the stereolithic model, representing the patient, and hand tightened. The spatial relationship of crowns to the model after hand tightening was determined using three-dimensional digital image correlation (3D DIC), an optical measurement technique. The crowns were then tightened using a torque driver to 20 Ncm and the relative crown positions were again recorded. Testing was repeated three times for each crown, and displacement of the crowns was compared between the hand-tightened and torqued states. Commercial image correlation software was used to analyze the data. Mean vertical and horizontal crown displacement values were calculated after torqueing. The interproximal contacts were evaluated before and after torquing using an 8-μm aluminum foil shim. There were vertical and horizontal differences in crown positions between hand tightening and torqueing. Although these were small in magnitude, detectable displacements occurred in both apical and facial directions. After hand tightening, the 8-μm shim could be dragged without tearing. However, after torque tightening, the interproximal contacts were too tight and the 8-μm shim could not be dragged without tearing. Differences between hand tightening and torque tightening should be taken into consideration during laboratory and clinical adjustments to prevent esthetic and functional complications.

Tooth-borne distraction of the lower anterior subapical segment for correction of class II malocclusion, subsequent to genioplasty

Alveolar distraction is mainly used to increase height and width of the alveolar crest. This technique, however, is not typically used for lengthening the perimeter of the dental arch or improving teeth axes. We applied alveolar distraction in a tooth-borne manner in the second stage of our original method and obtained favorable results. We therefore present an outline of this method. Genioplasty was first performed to create an infrastructure for sequential advancement of the subapical alveolar segment. After bone union, anterior subapical alveolar osteotomy was performed. The stump of the osteotomized dentate segment was moved forward without changing the incisal edge position, and a box-type bioabsorbable plate with four holes was fixed only onto the dentate segment using two screws. After a latency period, two distraction devices were placed bilaterally to the brackets and activated at 1.0 mm/day. After reaching the desired position, the distractor was immobilized, and then replaced by resin temporary teeth to retain the created space. After the consolidation period, orthodontic treatment was restarted and teeth moved into the newly created space. Bimaxillary surgery was performed after completing pre-surgical orthodontic treatment. Finally, both desirable occlusion and functional masticatory function were obtained. This tooth-borne distraction system is one applicable method for patients with skeletal class II and crowding of lower anterior teeth, achieving good results particularly in combination with our original method.

Incisive Papilla Line as a Guide to Predict Maxillary Anterior Tooth Display

Oh and Hansen Oh and Hansen Maxillary anterior tooth display should be predicted and controlled for an esthetic outcome in an edentulous patient.1 The customary prosthodontic procedure requires an occlusion wax rim to be contoured for adequate lip support and occlusal vertical dimension determination.2 The lip line is marked on the rim when the patient is in the full smile to determine the amount of tooth display and guide the selection of the artificial denture teeth. However, the smile line is dynamic, and the degree of anterior tooth display will vary depending on gender, race, lip fullness, age, and upper lip length.3,4 The upper lip length is measured from the base of the columela to the tip of the philtrum to aid in the selection and positioning of the anterior teeth.3 In general, the longer the upper lip, the less the maxillary teeth are visible, and vice versa. However, the lip length as measured according to the facial morphology may not always provide an accurate estimation of the relative amount of tooth display, both at rest and in the full smile, because of a large variability in maxillary lip line relative to the incisal edge position.3,4 The incisive papilla remains relatively constant in both vertical and horizontal locations, except when combined with excessive resorption of alveolar bone, and is frequently used as an anatomic landmark in arranging maxillary anterior teeth.2,5-7 The mean vertical distance between the incisive papilla and the incisal edges of maxIncisive papilla line as a guide to predict maxillary anterior tooth display

Guidelines for Maxillary Incisal Edge Position—A Pilot Study: The Key Is the Canine

The purpose of this pilot study was to evaluate the relationship between the vertical position of the maxillary central incisal edge and the maxillary canine relative to the maxillary lip line in repose of dentate patients. This may be beneficial for clinicians in establishing guidelines for the rehabilitation of edentulous patients. One hundred and four Caucasian dentate patients (59 men and 45 women) between the ages of 30 and 59 years were evaluated. A millimeter ruler was used to measure the maxillary right central incisor edge and the maxillary right canine tip to the maxillary lip in repose. Data were collected in reference to sex and age. For the female group, average central incisor exposure in relation to the relaxed maxillary lip line was 3.8 mm, and the range of exposure was -1 to +8 mm. In the 30- to 39-year olds (17 patients), the average was 4.1 mm with a range of 0 to 8 mm. The average in the 40- to 49-year-old group (16 patients) was 2.8 mm with a range of -1 to +6 mm. In 50- to 59-year olds (12 patients), the average was 1.8 mm with a range of -1 to +5 mm. In the male group, the average central incisor exposure was 2.5 mm, and the range was -3 to +7 mm. The average for the 30- to 39-year-old group (20 patients) was 3.2 mm with a range of 0 to 7 mm. For the 40- to 49-year group (18 patients), the average was 2.4 mm and for 50 to 61 years (21 patients), it was 1.4 mm with a range of -3 to +5 mm in both latter age groups. The canine position for the female group average exposure was 0 mm, with a range of -2 to +2 mm. For the 30- to 39-year old group, average exposure was 1 mm with a range of -1 to +2 mm. The 40- to 49-year-old group exposed an average of 0.4 mm with a range of -1 to +2 mm. For the 50- to 59-year old group, canine exposure was -0.5 mm with a range of -2 to +1 mm. The male average canine exposure was -0.5 mm, and the range was -3 to +2 mm. For the 30- to 39-year old group, the average was 0.9 mm with a range of -1 to +2 mm. The 40- to 49-year-old group exposed an average of 0.2 mm, with a range of -1 to +2 mm. For the 50- to 59-year old group, average was -0.9 mm with a range of -2 to +1 mm. There was a large range of maxillary central incisal exposure in relation to the maxillary lip line. The average dimension of central incisor exposure represented less than 30% of the subjects in the study and could not be used predictably to assess incisal edge position. The range of canine exposure was narrower. The average dimensions of canine exposure to the lip were within 1 mm for both men and women in all age groups. Further studies are needed to confirm these preliminary results. The average dimensions for the different sex and age groups related to canine exposure represented a greater proportion of the subjects. Therefore, it is suggested that the average canine exposure dimension can be used clinically to assess anterior incisor edge position when restoring edentulous patients.