Why we should assess gingival phenotypes in daily practice – gingival phenotype assessment tools & gingival phenotype classifications revisited

Kai Fischer

Table of Contents


Periodontal tissue phenotypes have been recently defined as the combination of gingival phenotype (GP) – earlier reported mainly as the gingival biotype – and bone morphotype. The main focus of this summary is to describe the GP as consisting of gingival thickness (GT) and gingival width (GW). GP has not only been investigated regarding its correlation with, for example, tooth shape, papilla height or buccal bone plate characteristics, but more importantly with regard to its impact on periodontal, implant, prosthetic and orthodontic treatment outcomes. Especially in the anterior segment, GP assessment before implant placement, particularly for immediate implants, is pivotal for esthetic but also for long-term stable results. Therefore, a standardized, reliable and easy-to-use method to assess the GP is warranted. Visibility of a periodontal probe inserted into the gingival sulcus seems the most appropriate approach: either the probe shines through the gingiva, reflecting a thin GP or the probe is not visible, hence, the GP is thick. Unfortunately, this dichotomous classification has two issues: 1) GP is a function of GT, hence, assessment in the intermediate area between thin versus thick might be challenging; 2) very thin/high risk cases as well as very thick/low risk cases cannot be identified. These observations led to the idea and development of a modified periodontal probe to enable GP classification into thin, moderate and thick phenotypes based on probe transparency as also described within the ITI SAC Classification Tool.

Phenotype assessment

The term “biotype” describes a group of organs sharing a specific genotype. The term “phenotype”, however, refers to the visible properties of an organism defined by the interaction of genetic determination – including the biotype – and environmental influences (Oxford, 2019). While the phenotype might change over time or be modified by surgical interventions, for instance, this may not necessarily apply to the biotype. However, both terms have been used synonymously when describing different entities of gingival thickness and other characteristics.

According to the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions (Jepsen et al., 2018) the term periodontal phenotype was proposed to be used primarily in order to simplify the nomenclature. It consists of the gingival phenotype (GP) and the bone morphotype. Furthermore, it is a combination of gingival thickness (GT) and width of keratinized gingiva (GW). As mentioned above, GP assessment should be part of treatment planning and risk evaluation before any dental intervention, including soft tissue manipulation.

Visual assessment without any standardized method cannot be recommended and is hardly possible even for experienced clinicians (Eghbali et al., 2009). Many different methods have been described in literature like transgingival probing, ultrasonic devices, gingival transparency (TRAN) or cone beam computed tomography (CBCT). TRAN is non-invasive and the only method that does not measure GT, but directly correlates the transparency of a periodontal probe tip through the gingival sulcus with GP. If the tip of the instrument shines through, it is categorized as a thin GP; if it does not shine through, it is a thick GP (Kan et al, 2003). In line with the ITI SAC classification, a double-ended periodontal probe is introduced to allow for a more sophisticated differentiation into thin, moderate and thick GP (Fischer et al, 2018).

Traditionally, it was believed that thin GP was associated with slender or triangular teeth with high papillae, short contact points, high soft and hard tissue scalloping as well as narrow GW, while the opposite was reported for thick GP cases ( Esfahrood et al. 2013). When stratifying subjects according to their GP, our group could not find any statistically significant differences in supra-crestal gingival height SCGH – embodying bone scalloping – or CS measurements. GW, on the other hand, was found to be correlated to GP with a wider zone of attached gingiva for thick GP. Papilla height, however, seems to have no or only a weak connection with GP. Buccal bone thickness, nevertheless, seems to be correlated with a higher GT, hence, a thicker buccal bone plate might be expected in thick GP cases (Cook et al, 2011). Moreover, the difference between thin and thick GP, with regard to GT and buccal bone thickness, seems to be around 0.2 mm (Frost et al., 2015). In earlier studies, GP assessment was not based on GT measurements but rather on crown shape (Olsson & Lindhe, 1991; Olsson & Lindhe, 1993). These studies clearly showed a correlation between CS, GW, probing depths and gingival scalloping, however, no difference in GT was found. Furthermore, GT might primarily depend on tooth type and GW (Eger et al., 1996). The influence of tooth position and angulations still needs to be evaluated and only little information has been reported on differences between posterior and anterior teeth.

Clinical relevance

Besides a large number of studies trying to characterize the GP, interventional trials have investigated its influence on different treatment outcomes. Furthermore, the harmony between the so-called white and pink esthetics plays an increasingly important role and should be monitored throughout therapy (Ronay et al., 2011). Flap thickness has been found to be a decisive factor, especially in plastic periodontal surgery, in achieving maximum root coverage (Baldi et al., 1999; Hwang & Wang, 2006 ).

A thick GP, consequently, might contribute to more favorable results, even without the need for soft tissue grafting (Rasperini et al, 2020). However, applying a connective tissue graft (CTG) might help to overcome this drawback in thin GP cases (Kahn et al., 2016). Furthermore in regenerative therapy of infrabony defects, patients with a thin-scalloped gingival biotype have an increased risk for advanced midfacial recession after therapy (Cosyn et al, 2012). Recently, Chow et al. (Chow et al., 2010) reported on the appearance of gingival papillae in relation to crown shape and gingival thickness. They found that gingival thickness was positively correlated with interproximal tissue height and hence with the appearance of the papillae.

GP has a major impact on treatment protocols and outcomes in implant dentistry. GP should be assessed for risk, especially in the anterior zone (Dawson et al., 2019). Mid-buccal recession is a common risk after immediate implant placement, and studies impose proper patient selection in relation to thick GP (Chen & Buser, 2014). In a systematic review, Cosyn et al. (Cosyn et al., 2014) concluded that a thick GP, among other risk indicators (e.g., immediate provisional crown, flapless surgery, intact facial socket wall), may contribute to minimizing the frequency of advanced recession following immediate implant treatment. In addition, restorative materials may be chosen according to the GB, hence a thicker peri-implant tissue may “camouflage” titanium or gold-alloy abutments (Sailer et al., 2007; Jung et al., 2007). Furthermore, thick peri-implant soft tissues seem to contribute to more stable bone levels (Linkevicius et al., 2009; Linkevicius et al, 2010). The peri-implant phenotype (PIP) was not defined until, very recently, Avila-Ortiz et al. (Avila-Ortiz et al., 2020) presented a standard definition including thresholds for mucosal thickness, width of keratinized mucosa and peri-implant bone thickness.


The most relevant reason for assessing GP is to identify high risk patients for soft tissue complications like the development of gingival/mucosal recession. A GP differentiation into thin, moderate and thick has been introduced in case risk assessment (simple, advanced, complex) for implant treatment in the esthetic zone (Dawson et al., 2009). In this context, a standardized tool for GP assessment is warranted from a clinical as well as a scientific perspective. This aspect together with the idea of developing a tool to differentiate between thin, moderate and thick GP led to the introduction of a double-ended periodontal probe (DBS12) based on TRAN (5). This tool was designed based on GT thresholds reported in the above study identifying extreme GP cases. TRAN methodology was introduced using a colored, plastic periodontal probe before tooth extraction. GT was measured after removing an upper anterior tooth and the GT threshold was artificially set to 1.0 mm to differentiate between thin and thick GP (4). The assessment showed 100% congruence between visual estimation and direct measurement for thin GP < 0.6 mm and thick GP > 1.0 mm.

Lately, it has been recommended to use traditional periodontal probes to assess GP in a standardized and replicable fashion with a GT threshold within the sulcus of 1.0 mm (2). Today, however, there is no exclusive standard periodontal probe when it comes to tip thickness, subdivision (1.0-mm steps vs. 3.0-mm steps) or tip color scheme (yellow vs. silver vs. black). These clinically measured values were approved in our recent pre-clinical model that also assessed applicability based on testing ratings by assessors with different levels of experience (Fischer et al., 2021). In this study, we used a traditional periodontal probe and two GP-specific methods (including DBS12). While seeing a much lower threshold of 0.5 mm compared to the often proposed 1.0 mm for a dichotomous TRAN approach using the traditional periodontal probe, threshold levels of 0.5 mm for thin vs. moderate and 0.8 mm for moderate vs. thick GP were seen for the other methodologies. A consensus between the assessors of > 90% was found for the DBS12 probe. Another clinical study assessing different methods to directly measure GT and GP found similar results with a 95% confidence interval < 1.0 mm even for very thick GP cases (Kloukos et al., 2018). Taking all these findings together, a threshold level of < 1.0 mm for thin GP and > 1.0 mm for thick GP seems questionable, at least when GT is measured within the gingival sulcus. Notably, a limitation of clinical studies is the very specific group of participants regarding ethnicity, age and inclusion criteria (e.g. periodontally healthy, non-restored teeth). Future research should include larger groups of varying age and different ethnicities to evaluate also the influence of gingival pigmentation. So far, hardly any interventional studies have been performed, hence, translation of the above findings into clinics are pending. In summary, GP shows a clear correlation with GT, GW and buccal bone thickness. GP assessment should be part of the daily clinical routine to identify in particular high-risk cases with a low GT. Utilization of a standardized approach including GP-specific tools is recommended.


The traditional dichotomous classification into thin vs. thick GP might not be sufficient to identify high and low risk cases for dental treatment procedures in the esthetic area; differentiation into thin, moderate and thick GP as part of the ITI SAC Assessment Tool applying a standardized and reproducible method is advocated. GP assessment based on transparency using a GP-specific tool inserted into the gingival sulcus seems to be an easy-to-perform, low-cost, non-invasive and highly sensitive approach – particularly for thin GP.


Kai Fischer
Kai Fischer
Dr. Kai Fischer is a periodontal specialist focusing on soft and hard tissue regeneration around teeth and implants working in private practice, Wuerzburg, Germany. He is also an external senior clinical lecturer at the Clinic of Conservative & Preventive Dentistry, Division for Periodontology & Peri-Implant Diseases, Zurich University, Switzerland. He is an ITI Fellow, a regular national and international lecturer and is involved in research activities in periodontology and implant dentistry (e.g., periodontal/peri-implant phenotypes, ridge preservation & soft tissue substitutes).

A Dictionary of Biology. Oxford: Oxford University Press, 2019.

Avila-Ortiz G, Gonzalez-Martin O, Couso-Queiruga E, Wang HL. The peri-implant phenotype. J Periodontol 2020;91:283-288.

Baldi C, Pini-Prato G, Pagliaro U, Nieri M, Saletta D, Muzzi L, et al. Coronally advanced flap procedure for root coverage. Is flap thickness a relevant predictor to achieve root coverage? A 19-case series. J Periodontol 1999;70:1077-1084.

Chen ST, Buser D. Esthetic outcomes following immediate and early implant placement in the anterior maxilla–a systematic review. Int J Oral Maxillofac Implants 2014;29 Suppl:186-215.

Chow YC, Eber RM, Tsao YP, Shotwell JL, Wang HL. Factors associated with the appearance of gingival papillae. J Clin Periodontol 2010;37:719-727.

Cook DR, Mealey BL, Verrett RG, Mills MP, Noujeim ME, Lasho DJ, et al. Relationship between clinical periodontal biotype and labial plate thickness: an in vivo study. Int J Periodontics Restorative Dent 2011;31:345-354.

Cosyn J, Cleymaet R, Hanselaer L, De Bruyn H. Regenerative periodontal therapy of infrabony defects using minimally invasive surgery and a collagen-enriched bovine-derived xenograft: a 1-year prospective study on clinical and aesthetic outcome. J Clin Periodontol 2012;39:979-986.

Cosyn J, Hooghe N, De Bruyn H. A systematic review on the frequency of advanced recession following single immediate implant treatment. J Clin Periodontol 2012;39:582-589.

Dawson A, Chen S, Buser D, Cordaro L, Martin W, Belser U. The SAC Classification in Implant Dentistry. London: Quintessenz Publishing Co. Ltd., 2009.

Eger T, Muller HP, Heinecke A. Ultrasonic determination of gingival thickness. Subject variation and influence of tooth type and clinical features. J Clin Periodontol 1996;23:839-845.

Eghbali A, De Rouck T, De Bruyn H, Cosyn J. The gingival biotype assessed by experienced and inexperienced clinicians. J Clin Periodontol 2009;36:958-963.

Esfahrood ZR, Kadkhodazadeh M, Talebi Ardakani MR. Gingival biotype: a review. Gen Dent 2013;61:14-17.

Fischer KR, Büchel J, Testori T, Rasperini G, Attin T, Schmidlin PR. Gingival phenotype assessment methods and classifications revisited: A preclinical study. Clinical oral investigations 2021;(accepted).

Fischer KR, Kunzlberger A, Donos N, Fickl S, Friedmann A. Gingival biotype revisited-novel classification and assessment tool. Clinical oral investigations 2018;22:443-448.

Frost NA, Mealey BL, Jones AA, Huynh-Ba G. Periodontal Biotype: Gingival Thickness as It Relates to Probe Visibility and Buccal Plate Thickness. J Periodontol 2015;86:1141-1149.

Hwang D, Wang HL. Flap thickness as a predictor of root coverage: a systematic review. J Periodontol 2006;77:1625-1634.

Jepsen S, Caton JG, Albandar JM, Bissada NF, Bouchard P, Cortellini P, et al. Periodontal manifestations of systemic diseases and developmental and acquired conditions: Consensus report of workgroup 3 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol 2018;89 Suppl 1:S237-S248.

Jung RE, Sailer I, Hammerle CH, Attin T, Schmidlin P. In vitro color changes of soft tissues caused by restorative materials. Int J Periodontics Restorative Dent 2007;27:251-257.

Kahn S, Almeida RA, Dias AT, Rodrigues WJ, Barceleiro MO, Taba M, Jr. Clinical Considerations on the Root Coverage of Gingival Recessions in Thin or Thick Biotype. Int J Periodontics Restorative Dent 2016;36:409-415.

Kan JY, Rungcharassaeng K, Umezu K, Kois JC. Dimensions of peri-implant mucosa: an evaluation of maxillary anterior single implants in humans. J Periodontol 2003;74:557-562.

Kloukos D, Koukos G, Doulis I, Sculean A, Stavropoulos A, Katsaros C. Gingival thickness assessment at the mandibular incisors with four methods: A cross-sectional study. J Periodontol 2018;89:1300-1309.

Linkevicius T, Apse P, Grybauskas S, Puisys A. Influence of thin mucosal tissues on crestal bone stability around implants with platform switching: a 1-year pilot study. Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons 2010;68:2272-2277.

Linkevicius T, Apse P, Grybauskas S, Puisys A. The influence of soft tissue thickness on crestal bone changes around implants: a 1-year prospective controlled clinical trial. Int J Oral Maxillofac Implants 2009;24:712-719.

Olsson M, Lindhe J, Marinello CP. On the relationship between crown form and clinical features of the gingiva in adolescents. J Clin Periodontol 1993;20:570-577.

Olsson M, Lindhe J. Periodontal characteristics in individuals with varying form of the upper central incisors. J Clin Periodontol 1991;18:78-82.

Rasperini G, Codari M, Paroni L, Aslan S, Limiroli E, Solis-Moreno C, et al. The Influence of Gingival Phenotype on the Outcomes of Coronally Advanced Flap: A Prospective Multicenter Study. Int J Periodontics Restorative Dent 2020;40:e27-e34.

Sailer I, Zembic A, Jung RE, Hammerle CH, Mattiola A. Single-tooth implant reconstructions: esthetic factors influencing the decision between titanium and zirconia abutments in anterior regions. Eur J Esthet Dent 2007;2:296-310.

Share on facebook
Share on twitter
Share on linkedin
Share on whatsapp
Fig. 20: Impression copings were picked up in the impression taken with polyether material in the anterior region and zinc oxide eugenol material in the posterior edentulous area
Clinical insights

Long-term success rate of mandibular locator implant-retained overdentures: How do we ensure predictable results?

Introduction Fully edentulous patients with severely resorbed ridges and unfavorable jaw relations often encounter difficulties with their conventional denture due to an impaired load-bearing capability, especially in the lower arch. Implant-retained overdentures (IODs) were proposed as an effective treatment for rehabilitating such patients to restore both function and esthetics and

Read More »
Practice development

Getting finances in order for success

We talk to Professor Salvatore Cantale, who lectures on the online ITI/IMD online Dental Practice Management course, about the role played by finance in running a successful practice. Tell us a little about yourself My name is Salvatore Cantale and I have been a professor at IMD for 10 years.

Read More »
ITI Scholarship interview

Interview series: Daniel’s ITI Scholarship experience

Every year in June, the ITI opens the application portal for its Scholarships. We took this opportunity to ask one of our current Scholars, Daniel Vegh from Hungary, about his experience, his daily work and what he likes the most about it. He started his Scholarship year in September 2021

Read More »