Journal of Oral Research and Review

: 2019  |  Volume : 11  |  Issue : 2  |  Page : 68--71

Relationship of fovea palatinae to vibrating line as a reliable guide in determining the posterior limit of maxillary denture

Indra Kumar Limbu, Bishal Babu Basnet 
 Department of Prosthodontics and Crown-Bridge, B.P. Koirala Institute of Health Sciences, Dharan, Nepal

Correspondence Address:
Bishal Babu Basnet
Department of Prosthodontics and Crown-Bridge, B.P. Koirala Institute of Health Sciences, Dharan


Introduction: Determining the posterior extent of maxillary denture is an important factor for retention and patient comfort. Among the landmarks, fovea palatina are utilized to extend the posterior denture border as an indicator of posterior palatal seal. The spatial relationship of fovea palatina to the posterior vibrating line has variations and is related to the types of soft palate. Aim: The aim of this study is to investigate the relationship between clinically determined posterior vibrating line and fovea palatina in Nepalese population and also compare the variations among the different types of soft palate. Materials and Methods: In 140 edentulous patients (57.1% male, mean age = 65.78 years), fovea palatina and posterior vibrating line were marked, and the distance between them was recorded. The comparisons were made in palatal types and gender as independent variables. The level of significance was 0.05 (95% confidence interval). Results: The mean distance of posterior vibrating line from the fovea was found to be 3.43 mm posteriorly. Statistically significant difference (P < 0.05) was observed among Class I, II, and III soft palate types in the distances measured from the fovea palatina to the posterior vibrating line. The gender showed no statistically significant difference. Conclusions: The fovea palatina was located more posteriorly in the Nepalese population and can be used cautiously for locating the posterior extent of maxillary denture.

How to cite this article:
Limbu IK, Basnet BB. Relationship of fovea palatinae to vibrating line as a reliable guide in determining the posterior limit of maxillary denture.J Oral Res Rev 2019;11:68-71

How to cite this URL:
Limbu IK, Basnet BB. Relationship of fovea palatinae to vibrating line as a reliable guide in determining the posterior limit of maxillary denture. J Oral Res Rev [serial online] 2019 [cited 2019 Aug 25 ];11:68-71
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Although a large number of people have started to retain their teeth in the old age, still a considerable proportion of patients need complete dentures for dentition.[1],[2] Determining the location of the posterior border of the maxillary denture plays an important role in its retention and patient comfort.[3] There is a general agreement that the posterior extent of the maxillary denture should extend at least to the vibrating line or the border should terminate to the vibrating line.[4] The vibrating line is an imaginary line that is drawn across the palate at the beginning of the movement in the soft palate when an individual says “ah.” It is physiologically present at the junction of movable and immovable portions of the soft palate.[2] It should not be confused with the anatomic junction of hard and soft palates[5] and is largely dependent on the visual observation.[6] The location of the vibrating lines varies with the location of the contour of the soft palate.[7]

Since 1920, more than fifty publications have described or evaluated techniques for locating the posterior border of the upper denture.[8] One of the easiest and most commonly practiced methods for determining the extent of the posterior border of the maxillary complete denture is using the anatomical landmarks such as fovea palatinae and hamular notches.[3] Fovea can be used as a reliable guide for determining the posterior border of the maxillary denture.[9],[10] The posterior border can be located with great accuracy if it is possible to see two small pits (fovea palatinae) one on the either side of the midline on the anterior part of the soft palate.[9] However, there are great variations regarding the position of the fovea palatinae in relation to the vibrating lines.[11] Soft palate is classified into three categories based on the angle the soft palate makes with the hard palate.[12] This could also impact on the positioning of the posterior border of maxillary denture.

The rationale of this study is to relate the location of the fovea palatina to posterior vibrating line in different classes of soft palate so that its reliability as a landmark in determining the posterior limit of the maxillary denture can be established.

 Materials and Methods

This study was conducted in the Department of Prosthodontics, College of Dental Surgery, B.P. Koirala Institute of Health Sciences (BPKIHS), Dharan, Nepal. The study was done after receiving ethical clearance from the Institutional Review Committee of BPKIHS. The study was cross sectional and observational with conveniently selected 140 edentulous patients.

Completely edentulous patients with normal healthy mucosa were selected in this study. Patients with cleft palate, congenital and acquired craniofacial anomalies, and any pathologies affecting oral cavities were not included in this study. Informed consent was taken verbally and in written form from the selected participants.

The selected participant was seated on a dental chair in upright position with head erect and asked to open the mouth wide. The palate of each participant was examined, whether soft palate type Class I, II, and III as described by Millsap,[12] and was determined by visual inspection, and the findings were recorded in a spreadsheet. Fovea palatinae were marked with the help of an indelible pencil.

The participant was instructed to pronounce “ah” sound in a normal unexaggerated fashion repetitively, and the vibrating line was marked using the indelible pencil. After marking both the fovea palatinae and posterior vibrating line, the distance between the two was measured with a divider and a scale. When more than two fovea were present and their position was antero-posterior to each other, the fovea nearer to the vibrating line was considered.

The recorded data were entered into Microsoft Excel and were further analyzed with SPSS software version 16 for Windows (SPSS version 16 (IBM Corp). Shapiro–Wilk test was used for the test of normality. Mann–Whitney U-test was applied to compare the mean distance between fovea palatinae and posterior vibrating line in males and females. Kruskal–Wallis test was applied to compare the mean distance among different soft palate classes. The level of significance was kept at 0.05 (95% confidence interval).


In this study, 140 completely edentulous patients (male 57.1% and female 42.9%) were enrolled for examination. The mean age of the population was 65.78 years (standard deviation = 9.015), with the maximum age of 94 years and the minimum age of 44 years. The mean duration of denture use was 3.74 years.

Among the participants, Class II palate was most prevalent (57.9%), followed by Class I (27.1%) and Class III (15%). In 33 patients (23.6%), fovea palatina was present on the posterior vibrating line, whereas those having vibrating line posterior to fovea palatinae were 96 (68.6%) and those having vibrating line anterior to fovea palatinae were 3 (2.1%). Fovea palatina was not appreciated in eight patients.

The mean distance from the vibrating line to fovea palatinae was 3.43 mm posteriorly.

Comparison of mean distance from vibrating line to fovea palatinae in males and females is presented in [Table 1]. Mann–Whitney U-test showed the difference to be statistically insignificant (P = 0.247).{Table 1}

Based on soft palate classification, distance varied from 1.71 to 5.77 mm. The variation is shown in [Table 2]. The difference among the classes was found to be statistically significant (P = 0.001) by Kruskal–Wallis test. The post hoc analyses with Mann–Whitney test showed statistically significant differences between the two classes [Table 3].{Table 2}{Table 3}


In order to gain good retention of the maxillary complete denture, an adequate seal must be obtained along the posterior border of the denture.[9] The posterior palatal seal which is present in the posterior border of the maxillary prosthesis maintains contact with the anterior portion of the soft palate and helps in the retention of the maxillary denture.[13] The posterior palatal seal area extends medially from one hamular notch to other.[2],[13] Rashedi and Petropolous in one educational survey suggested that a large percentage of the teaching hospitals in the USA used the one vibrating line concept.[14] Zarb also advocated single vibrating line.[2] The authors who suggested single vibrating line had described different methods such as nose blowing[11] and phonation method[2],[10] for recording vibrating line; however, certain schools in the USA, Nepal, and India follow the concept of two vibrating lines[15] and the posterior palatal seal is recorded between the anterior and posterior vibrating lines.[13] Winkler recommended Valsalva maneuver for locating the anterior vibrating line. He suggested to record the posterior vibrating line by instructing the patient to say “ah” in a short burst in a nonexaggerated fashion.[13]. Silverman also proposed two vibrating lines. He described the posterior palatal seal as the tissue zone between anterior and posterior flexion lines. He suggested recording the anterior line by instructing the patient to say “ah” in an abrupt vigorous burst and later in a brief burst of soft speech.[16] In the present study, only the posterior vibrating line was considered as all the authors agree that posterior vibrating line marks the distal extension of the denture base. If the posterior border does not reach this compressible seal area, retention will be poor because of improper seal.[9] If the border extends beyond the vibrating line, seal will be broken when the soft palate rises during deglutition and speech and the patient is also likely to complain of nausea and discomfort.[13]

Some authors advocate that anatomic landmark like fovea palatinea can play an important role in determining the posterior extent of the maxillary denture. Their assumption was based on the fact that the vibrating lines are generally found along the fovea palatinea,[3] but other authors like Chen had concluded that fovea palatinea are unreliable guide for locating the central portion of the posterior border of the maxillary border. Chen found that majority of the individuals had fovea either on or behind the anterior vibrating line.[11] According to Lye, foveae are located on an average of 1.31 mm anterior to the anterior vibrating line.[10] In this study, majority of the individuals had posterior vibrating line behind the fovea palatinae. This is in accordance with Lye who found that fovea palatina was anterior to the vibrating line. However, this is in contradiction with Zarb who reported that, in midline, the vibrating line (posterior) usually passes 1–2 mm anterior to the fovea palatinea.[2] The present study does not confirm whether it is in accordance or contradiction with the finding of Chen as we have considered posterior vibrating line in contrast to his anterior vibrating line. His posterior position of fovea might be anterior or posterior to our posterior vibrating line.

Millsap has proposed a classification of soft palate depending on the angulation formed by soft palate with hard palate.[12] Class I soft palate is horizontal and turns downward around 10° to the hard palate at the mid palatal raphe. Class III is steep and turns downward acutely around 70°. Class II is moderate and makes 45° with the hard palate.[12] Different authors have studied the position of fovea with different types of soft palate contour. The study done by Keng indicates that there is statistically highly significant difference between the distance of the vibrating line and the fovea for three different contours of the soft palate. According to him, in Class III soft palate, vibrating line was at or 0.89 mm in front of the fovea. In Class I, vibrating line was 4.2 mm in front of the fovea. In Class II, the vibrating line was 2.30 mm in front of the fovea.[7] However, in the present study, we found that vibrating line was posterior to the fovea at the mean of 1.71 mm in Class III, 2.83 mm in Class II, and 5.77 mm in Class I.

In another study done by Kyung et al.,[17] they found anterior vibrating line anterior to the fovea at a mean distance of 2.58 ± 1.19 mm and posterior vibrating line posterior to the fovea at a mean distance of 0.71 ± 0.68 mm. They also stated that larger posterior palatal seal can be obtained with flat soft palate. This is in agreement with the present study however, the distance between fovea and posterior vibrating line was higher in present study than their finding.

Limitations of the study were only posterior vibrating line was considered and relatively small sample size was taken. Furthermore, ethnic variation was not studied in our study.


Considering their proximity with posterior vibrating line, in Class III soft palate, fovea could be a reliable reference for locating the posterior border of maxillary denture. In case of Class I and II cases, it is recommended to determine the posterior limit by locating the vibrating line. Due to greater distance from fovea to the vibrating line in Class I cases, wide posterior palatal seal could be utilized. In Class III palatal contour, there is a narrow zone of palatal seal area.


We would like to acknowledge all the patients who took part in this study. We also like to thank Prof. Dr. Pramita Suwal, Head of the Department, for allowing us to conduct the study. The staff members of the department are acknowledged for their support.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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