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 Table of Contents  
Year : 2023  |  Volume : 15  |  Issue : 5  |  Page : 443-448

Palatogingival groove: Prevalence, characteristics and implications in a cross-sectional study in Rio de Janeiro-Brazil

1 Postgraduate Program in Dentistry of Health Institute of Nova Friburgo, Fluminense Federal University, Nova Friburgo, RJ, Brazil
2 Department of Specific Formation, School of Dentistry, Fluminense Federal University, Nova Friburgo, Brazil
3 Department of Periodontology and Implantodontology, School of Dentistry, Federal University of Uberlândia, Uberlândia, MG, Brazil

Date of Submission08-Mar-2023
Date of Decision25-Sep-2023
Date of Acceptance27-Sep-2023
Date of Web Publication30-Oct-2023

Correspondence Address:
Prof. Elizangela Partata Zuza
Department of Periodontology and Implantodontology, School of Dentistry, Federal University of Uberlândia (UFU), Rua República do Piratini, 1102, Bloco 4L. Umuarama. Cep 34405-266, Uberlândia, MG
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jioh.jioh_61_23

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Aim: Palatogingival groove (PGG) is a morphological defect that usually affects maxillary incisors and may be related to periodontal and endodontic disease. The aim of this study was to evaluate the prevalence, characteristics, and clinical implications of the PGG in a Brazilian population. Materials and Methods: A convenience sample with 169 consecutive participants was evaluated in a cross-sectional study from September 2021 to May 2022. Upper anterior teeth were evaluated by a single examiner considering the presence of PGG, its characteristics and the presence of caries, periodontal and endodontic disease. Chi-square test and logistic regression were applied and P value was set at 5%. Results: PGG prevalence was 21.67% in individuals and 5.9% in teeth. A logistic regression did not reveal significant differences between sex [female: odds radio (OR) 1 and male: OR 0.53] and race (white: OR 1; black: OR 0.81; brown: OR 0.70). The highest prevalence was found in the upper lateral incisors (68.6%), in the cingulum (80.39%), with greater occurrence in the mid-palatal face of the tooth (39.21%). A high prevalence of bleeding on probing (83.8%) and caries (37.8%) was found in teeth with PGG, but no pulp alterations were found. Conclusions: PGG prevalence is high when the number of individuals is considered, and the tooth more frequently affected by PGG is the upper lateral incisor, with greater occurrence in the mid-palatal and cingulum face. In addition to incisors, canines also can be affected by PGG. Teeth with PGG may present high rates of biofilm accumulation, periodontal inflammation, and caries.

Keywords: Endodontics, Incisor, Palatogingival Groove, Periodontics, Tooth Abnormalities

How to cite this article:
Demore FP, Cecília MS, Souza AA, Zuza EP. Palatogingival groove: Prevalence, characteristics and implications in a cross-sectional study in Rio de Janeiro-Brazil. J Int Oral Health 2023;15:443-8

How to cite this URL:
Demore FP, Cecília MS, Souza AA, Zuza EP. Palatogingival groove: Prevalence, characteristics and implications in a cross-sectional study in Rio de Janeiro-Brazil. J Int Oral Health [serial online] 2023 [cited 2023 Dec 6];15:443-8. Available from:

  Introduction Top

Palatogingival groove (PGG), also known as distolingual groove, palate radicular groove, coronoradicular groove or radiculo lingual groove, is a morphological alteration that occurs during tooth development, of uncertain etiology.[1],[2] It usually affects the palatal surface of permanent maxillary incisors, being more prevalent in the maxillary lateral incisor.[3],[4],[5],[6],[7] The prevalence of PGG ranges from 1.61% to 44.6%, regardless of race or sex.[4],[6],[8]

PGG normally begins in the region of the central fossa or in the cingulum, and its extension may be limited to the dental crown or involve the root surface, proceeding in a distal, central, or mesial direction. The depth of the PGG can be classified as a mild depression, wrinkle, or even fissure.[7],[9],[10],[11] In rare cases, the PGG can be deep enough to cause a direct communication between the pulp and the periodontium.[9],[11],[12]

Teeth with PGG usually present worse periodontal health, and the presence of a periodontal pocket is a common finding, which makes it possible to state that the presence of PGG is a predisposing factor for localized periodontitis.[3],[4],[5],[6],[10] Endodontic-periodontal lesions can also happen, requiring rigorous interdisciplinary measures for treatment.[10],[13],[14],[15],[16]

The PGG can compromise the integrity and prognosis of the affected teeth, what makes the early diagnosis of this morphological alteration important to reduce the risk of complications. The present study attempts to evaluate the prevalence of the PGG and to observe its characteristics and clinical implications.

  Materials and Methods Top

Setting and design

This institutional based cross-sectional study was carried out in a Brazilian population, considering a convenience sample from a private practice in the city of Rio de Janeiro—RJ and in the Dental Clinics of the Health Institute of Nova Friburgo of the Federal Fluminense University (ISNF/UFF), after approval from the Research Ethics Committee of ISNF/UFF (Protocol 4.947.609). The study used census-type sampling, where all patients treated in the period from September 2021 to May 2022 were invited to participate in the study and all those who agreed to participate voluntarily completed the Informed Consent Form.

Sampling criteria

The sample size calculation was performed using the confidence interval (CI) of a proportion according to the website There was considered a study that found proportion of 8.3% of PGG.[20] For this calculation, we considered an error of 5% and a confidence level of 95%. Thus, the sample size calculation included 117 individuals.

The evaluation was performed by a single evaluator, trained and calibrated. Training and prior calibration were carried out with an experienced researcher in the area. For calibration, the probing depth (PD) measurement was applied in six sites per tooth (mesiobuccal, buccal, distobuccal, mesiopalatine, palatine, and distopalatine) on the central incisors, laterals, and upper canines. Calibration was performed with six participants, at two different times, with a one-hour interval between assessments. PD was measured at a total of 216 sites and the intraclass correlation test for continuous data was used for two related samples, with excellent replicability (CI = 0.9194; P < 0.0001).

Inclusion criteria were: (1) presence of central, lateral, and upper canine teeth; (2) age between 18 and 65 years. Exclusion criteria were: (1) presence of restoration on the palatal surface or prosthetic crown of the maxillary anterior teeth; (2) wear and/or erosion on the palatal surface; (3) absence of all anterior maxillary teeth.


Information such as patient’s name, sex, race, and age were collected from all participants. PGG classification was based on Hou and Tsai[6] study, considering the identification of the tooth, face of the tooth involved, origin and direction of the sulcus. Teeth with PGG were also evaluated considering: (A) visible plaque—present or absent[17]; (B) bleeding on probing—present or Absent[18]; (C) probing depth (PD)[18]—measurement in millimeters at six sites per tooth (mesio buccal, buccal, distobuccal, mesiopalatal, palatal, and distopalatal), using a PCP-15 millimeter periodontal probe (Hu-Friedy, Chicago) and classified between two scores: ≤3 mm and ≥4 mm; (D) clinical attachment level (CAL)[18]—also classified between two scores: ≤3 mm and ≥4 mm; (E) pulp sensitivity test—carried out cold (‐50ºC) using refrigerant gas (Roeko, Langenau, Germany), under relative isolation with a cotton roll. Responses were classified as positive without alteration, positive with alteration, or negative; (F) vertical and horizontal percussion test—positive or negative; (G) clinical assessment of caries—performed after drying the tooth with the air spray and visual inspection. The caries diagnosis was considered as present (active or inactive caries) or absent. It was considered as inactive if it had a smooth and shiny surface with a whitish color or if it had a hard and darkened surface; or active, when the enamel surface showed a rough and opaque white spot.[19]

Statistical analysis

Prevalence of radicular grooves was calculated at patient and tooth level. Extent of the defects was assessed as the proportion of affected tooth in patients with the condition. The Chi-square test (χ2) and a logistic regression were applied to compare the demographic characteristics of the participants and the clinical conditions of the teeth with PGG. The findings were treated statistically using the BioEstat 5.3 (Mamirauá, Pará, Brazil) and RStudio 2023 program (Posit, Boston). The significance level considered in all analyses was 5%.

  Results Top

The flowchart depicting the participants selection process can be seen in [Figure 1]. A convenience sample with 169 consecutive participants was evaluated in a cross-sectional study from September 2021 to May 2022. PGG prevalence was 21.67% in individuals and 5.9% in teeth. It was not found statistical difference between sex [Table 1] and race [Table 2]. The average age was 34.03 ± 9.3 years. A logistic regression using race and sex as dependent variables and presence of PGG as independent variable was performed and no significant differences were observed in sex or race [Table 3].
Figure 1: Study flowchart

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Table 1: Distribution of PGG by sex

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Table 2: Distribution of PGG by race

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Table 3: Logistic as regression with presence of PGG dependent variable

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The tooth most affected by PGG was the upper lateral incisor (68.6%), followed by the upper canines (27.45%) and the upper central incisor (3.9%). The uni/bilateral relationship between each group of teeth can be seen in [Figure 2].
Figure 2: Distribution of PGG by group of teeth and relationship between uni/bilaterality

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The cingulum was the most common PGG’s site of origin (80.39%), which was statistically different in relation to the central fossa (19.60%) (P = 0.0006). Considering the direction taken by the PGG, four different patterns were identified [Figure 3]. In most of the cases (39.21%), the PGG extended straight along the mid-palatal face of the tooth, followed by the inverted “V” (37.25%), directed toward both the mesial and distal faces of the tooth. The sulci present on the mesial (11.76%) and distal (11.76%) faces showed identical frequencies and were identified less frequently.
Figure 3: Clinical classification of PGG direction by palatal aspect

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It was found a low prevalence (2.7%) of teeth with PGG and PD and CAL ≥ 4 mm. However, a high prevalence (83.8%) of bleeding on probing was observed in teeth with PGG. 43.13% of the teeth with PGG had visible plaque in the sulcus region and 37.8% had caries in its inactive form. No active caries was detected. No relationship was observed between the presence of PGG and changes in pulp sensitivity. Vertical and horizontal percussion was normal in all evaluated cases.

  Discussion Top

When evaluating the prevalence of PGG in different studies, it is necessary to observe that the basis of the percentage calculation considers different aspects, and that this causes great variation in the percentages found. Some studies assess the prevalence of PGG considering the number of individuals,[3],[6],[21] whereas others consider the number of teeth.[22],[23],[24],[25],[26] In the few studies have evaluated the prevalence of PGG considering the number of individuals, the results showed prevalence above 8%,[3],[20],[21] reaching 44.6%.[6] In the present study, 21.67% of the evaluated individuals presented PGG.

Studies that found a PGG prevalence lower than 5% considered the percentage of teeth in their calculation.[22],[23],[24],[25],[26] These studies used extracted teeth to assess the prevalence of PGG, and the lack of information about the reasons for the extraction of these teeth and the lack of definition of the inclusion/exclusion criteria in the study may lead to bias. In addition, all studies that evaluated the prevalence of PGG in individuals and in teeth, concomitantly, found prevalence at least twice as high when the calculation basis considered the number of individuals and not the number of teeth. [3, 6, 20, 21] The same occurred in the present study, where only 5.9% of the teeth had PGG, whereas 21.67% of the individuals presented the alteration. With this, we can assume that, if the studies that evaluated the prevalence in number of teeth also calculated the prevalence in number of individuals with PGG, they would find higher numbers.

The prevalence of individuals with PGG in the present study was similar to Pinheiro[7] study, also carried out in Brazil and in a dentally assisted population, which found this alteration in 19.8% of the evaluated individuals. The study that found the highest prevalence (44.6%) was carried out in a population consisting only of Chinese individuals,[6] which may indicate a possible racial influence on tooth morphology.

An important factor to be highlighted in the present study is that, in addition to the upper central incisor and upper lateral incisor, the upper canines were also included in the evaluation. The PGG prevalence usually is evaluated considering only upper permanent incisors, but canines are also teeth that can have developmental grooves and there are no other clinical studies evaluating the prevalence of PGG in these teeth. In our sample, canines were the second type of tooth with the highest prevalence of the alteration (27.45% of the teeth with PPG).

Only two studies were found in the literature evaluating the prevalence of PGG including canines, but, in those, a retrospective cone-beam computed tomography analysis was done and no canine with PGG was identified.[26],[27] These studies also found lower prevalence of PGG in upper incisors (1.88% and 0.9% respectively) in comparison with the present study. In addition to using diagnosis through image exams instead of clinical evaluation, the differences can be explained by the fact that the mentioned studies only included the sulci that extended up to or beyond the cementoenamel junction. In the current study, the clinical evaluation was limited to the coronary surface and because of the overlying gingival tissues and alveolar bone, it was not possible to state whether the grooves extended across the root surface or whether they were limited to the coronal surface. The possibility that the extension of the sulcus in part of our sample is limited to the coronal surface can justify the higher prevalence found.

The tooth most frequently affected by PGG in this study was the upper lateral incisor. These data corroborate those found in the literature, which reports that the upper lateral incisor is the tooth that most frequently presents PGG.[3],[4],[7],[20],[23],[24]

The most common site of origin of the PGG was the dental cingulum (80.39%). These data are similar to those of a case series presentation, which identified the cingulum as the point of origin of the PGG in 100% of the cases.[10] On the other hand, other findings verified a higher prevalence of PGG in the central fossa.[9],[27],[28]

Some authors classified the PGG into different types based on severity, using tomographic images[29] and morphologic analyses during intentional replantation.[10] However, there is no consensus on this classification when the analysis is performed with visual clinical examination evaluating teeth in the mouth. In the current study, the direction of sulcus in relation to the cingulum/central fossa followed the mid-palatal direction (39.21% of cases). Corroborating our results, other studies also found a higher frequency of PGG on the mid-palatal surface.[6],[8],[26] On the other hand, some studies[4],[9],[11] reported the distal surface to be the direction most commonly followed by the PGG. The second most commonly observed characteristic in our results was the groove in the shape of an inverted “V,” with the apex pointing to the incisal edge of the dental crown and in the apical mesial and distal direction (37.25%).

Regarding the clinical implications of teeth with PGG, periodontal health seems to be most affected by the presence of the sulcus. We found a high frequency (83.8%) of bleeding on probing in teeth with PGG. The presence of poorer periodontal health is a common finding in teeth with PGG, and other researchers have also found a trend towards higher rates of gingival inflammation in these teeth.[3],[4],[5],[6],[8],[20]

However, regarding the presence of periodontal pockets, only 2.7% of teeth with PGG had a probing depth and clinical attachment level ≥4 mm in our sample. These results are similar to Pinheiro[7] study, that found a low association (5%) between the presence of PGG and greater probing depth. Nevertheless, Hou and Tsai[6] and Pécora and Cruz Filho[5] found higher prevalence, such as 26%and 52%, respectively, of periodontal pockets associated with the PGG. This lower frequency of periodontal pockets in the present study may be related to the average age of the participants, which was 34 years. The absence of lesions in relatively young individuals can change as the patient ages and periodontal degradation has time to develop.

Probably because it is a region of anatomical irregularity (which can make cleaning difficult), 43.13% of the teeth with PGG had visible plaque in the sulcus region. Regarding caries, 37.8% of the teeth with PGG had (inactive) caries lesions in the PGG region. This prevalence was much higher than that found in Pinheiro[7] study where the author found caries in only 6.75% of the teeth with PGG. To the best of our knowledge, no other studies have evaluated the presence of caries in teeth with PGG, and future studies should evaluate this relationship.

Although a high frequency of these alterations have been found in the current study, it is not possible to state the association between PGG and the occurrence of these clinical implications, because only information regardless teeth with PGG were collected—with no control group. Regarding the pulp condition, no alterations were found on the pulp sensitivity test, nor on vertical/horizontal percussion test. However, the pulp condition of teeth with PGG must always be evaluated. A study with microscopic analysis revealed that in 35% of teeth with PGG, there was a communication between the root canal and PGG.[11]

It can therefore be concluded that the prevalence of PGG is higher than what previous studies using extracted teeth showed and, in additional to the incisors, canines also can be affected by this morphological alteration. Teeth with PGG usually have more biofilm accumulation and so, additionally to the poor periodontal health reported by several studies and confirmed in this study, the presence of caries lesions seems to be a common finding and should be investigated in future clinical studies. Future studies should combine clinical evaluation in human beings and use cone-beam computed tomography to better measure the characteristics and clinical implications of PGG.

Future studies could improve the clinical characteristics evaluation with the use of cone-beam computed tomography. With this exam it would be possible to determine the deep of the sulcus and its extension, to better correlate the morphological alteration with clinical implications.

  Conclusion Top

The present study demonstrates that PGG is a frequent alteration in upper permanent incisors and also in canines. A prevalence of 21.67% of PGG in individuals was found and the tooth more frequently affected by PGG was the upper lateral incisor, with greater occurrence in the mid-palatal and cingulum face. In addition to high rates of biofilm accumulation and periodontal inflammation, clinical implications commonly related to the presence of PGG, the present study also found a high prevalence of caries in teeth with PGG.


We are grateful for the general support of the Department of Specific Training ISNF and the Discipline of Interdisciplinary Clinic III for the availability of physical resources to carry out the research.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

Authors’ contributions

M.S.C; Design and Definition of Intellectual Content, AAS, PPZ; Investigation, Acquisition of Data. F.P.D; Analysis and Interpretation of Data: F.P.D, M.S.C and E.P.Z; Manuscript Writing, Review and Edition and final approval to manuscript.

Ethical policy and institutional review board statement

The study was approved by the Research Ethics Committee of ISNF/UFF (Protocol 4.947.609) on September 1st, 2021. All the procedures were performed as per the ethical guidelines laid down by Declaration of Helsinki (2013).

Patient declaration of consent

All patients signed a consent authorizing the clinical examination and publication of the data for research and educational purposes.

Data availability statement

The authors decide to make the data available if necessary.

  References Top

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  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2], [Table 3]


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