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JEPSEN et al .
b. Phenotype: Appearance of an organ based on a multifactorial combination of genetic traits and environmental factors (its ex‐ pression includes the biotype). The phenotype indicates a dimension that may change through time depending upon environmental factors and clinical intervention and can be site‐specific (phenotype can be modified, not the geno‐ type). Periodontal phenotype is determined by gingival phenotype (gingival thickness, keratinized tissue width), and bone morphotype (thickness of the buccal bone plate). Thin phenotype increases risk for gingival recession. Thin phe‐ notypes are more prone to develop increasing recession lesions. 19,20 How can the periodontal phenotype be assessed in a standardized and reproducible way? It can be assessed by using a periodontal probe to measure the gin‐ gival thickness (GT) observing the periodontal probe shining through gingival tissue after being inserted into the sulcus:
Does intrasulcular restorative margin placement influence the development of gingival recession? Intrasulcular restorative/prosthetic cervical margin placement may be associated with the development of gingival recession particu‐ larly in a thin periodontal phenotype.
What is the effect of orthodontic treatment on the development of gingival recession?
1. Several studies report the observation of gingival recessions following orthodontic treatment (mainly on the effect of man‐ dibular incisor proclination). The reported prevalence spans 5% to 12% at the end of treatment. Authors report an increase of the prevalence up to 47% in long‐term observations (5 years). 27‒30 One study reported a correlation between lower incisor proclination and thin phenotype. 31 2. Direction of the tooth movement and the bucco‐lingual thickness of the gingiva may play important roles in soft tissue alteration during orthodontic treatment. 32 Do we need a new classification of gingival recession? The group suggests the need for a new classification based upon anatomy.
1) Probe visible: thin (≤1 mm). 2) Probe not visible: thick (> 1 mm).
Different types of probes are used to assess GT: CPU 15 UNC, Hu‐ Friedy, 21 SE Probe SD12 Yellow, American Eagle Instruments. 22 Note: Probe visibility was tested in samples of subjects with unknown gingival pigmentation. It is unknown if the same out‐ comes are to be expected in populations with different gingival pigmentation. A novel electronic customized caliper has been recently proposed to measure the gingival thickness with a controlled force. 23 Additional information on the three‐dimensional gingival volume can be obtained by measuring the keratinized tissue width (KTW) from the gingival margin to the mucogingival junction. Bone mor- photypes have been measured radiographically with cone‐beam computed tomography (CBCT). The group does not recommend the application of CBCT in this context. There is evidence reporting a correlation between gingival thickness and buccal bone plate. 24,25 To date, periodontal phenotype cannot be assessed in full, while gingi‐ val phenotype (GT and KTW) can be assessed in a standardized and reproducible way. Is there a certain amount (thickness and width) of gingiva necessary to maintain periodontal health? Any amount of gingiva is sufficient to maintain periodontal health when optimal oral hygiene is attainable. Does improper toothbrushing influence the development and progression of gingival recessions? Data are inconclusive. Some studies reported a positive association, some a negative, and some no association. 26
Case definitions and diagnostic considerations
Mucogingival conditions Within the individual variability of anatomy and morphology “normal mucogingival condition” can be defined as the “absence of pathosis (i.e. gingival recession, gingivitis, periodontitis)”. There will be ex‐ treme conditions without obvious pathosis in which the deviation from what is considered “normal” in the oral cavity lies outside of the range of individual variability. 2 a) Mucogingival condition with gingival recessions A case with gingival recession presents with an apical shift of the gingival margin ( recession depth ). Relevant features contributing to the description of this condition are 1) the interdental clinical attach‐ ment level, 2) the gingival phenotype (g ingival thickness and kerati- nized tissue width ), 3) root surface condition (presence / absence of NCCL or caries), 4) detection of the CEJ, 5) tooth position, 6) ab‐ errant frenum, and 7) number of adjacent recessions. Presence of recession can cause esthetic problems to the patients and be associ‐ ated with dentin hypersensitivity. b) Mucogingival condition without gingival recessions A case without gingival recession can be described as the gingival phenotype (g ingival thickness and keratinized tissue width) , either at the entire dentition, or at individual sites. Relevant features
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