Periodontal Phenotypes Recession and Anomalies Flashcards
Define the terms genotype, phenotype and morphotype
Genotype
• The set of genes or genetic composition/sequence of an individual organism
• Non- modifiable
Phenotype
• The observable characteristics of an individual organism, which are influenced by both its genotype and the environment
Morphotype
• Individual or set of individuals within a population with a distinctive physical characteristic (E.g. alveolar bone morphotypes – scalloped, flat)
Define ‘normal mucogingival condition’
Absence of pathosis or disease’ (i.e. gingival recession, gingivitis, periodontitis), with variability evident amongst individuals
Give examples of mucogingival conditions
Lack of keratinized tissue, position and shape of frena and shallow vestibular depth can be associated with periodontal health
List the three types of periodontal phenotypes
Thin scalloped biotype
Thick flat biotype
Thick scalloped biotype
For the thin scalloped biotype, list:
- Gingival thickness/keratinised tissue
- Born morphotype
- Tooth dimension
Gingival thickness/ keratinised tissue:
• Narrow zone of keratinised gingiva
Born morphotype:
• Thin alveolar bone
Tooth dimension:
• Slender, triangular crown
For the thick flat biotype, list:
- Gingival thickness/keratinised tissue
- Born morphotype
- Tooth dimension
Gingival thickness/ keratinised tissue:
• Thick, fibrotic gingiva
Born morphotype:
• Thicker alveolar bone
Tooth dimension:
• Square shaped teeth
For the thick scalloped biotype, list:
- Gingival thickness/keratinised tissue
- Born morphotype
- Tooth dimension
Gingival thickness/ keratinised tissue:
• Fibrotic gingiva with pronounced gingival scalloping
Born morphotype:
• Thick
Tooth dimension:
• Thin, slender narrow teeth
Describe the assessment methods used to determine periodontal biotype
Transgingival probing (accuracy to the nearest 0.5 mm), performed under local anaesthesia
• Ultrasonic measurement: Probe visibility after its placement in the facial sulcus
What are the measurements for ‘thin’ and ‘thick’ gingiva
Gingiva is defined as thin (≤1.0 mm) or thick (>1mm) upon the observation of the periodontal probe visibility through the gingiva
How do you measure Keratinised Tissue Width (KTW) and bone thickness?
KTW
• Easily measured with a periodontal probe positioned between the gingival margin and the muco-gingival junction
• 2mm of KTW and 1mm of attached gingiva are desirable around teeth to maintain periodontal health
Bone Thickness
• Assessment through Cone Beam-computed Tomography (CBCT) has high diagnostic accuracy, exposure to radiation has potential harmful effect
How can tooth positioning affect phenotype?
For example, teeth tilted or rotated labially
• the labial bony plate is thinner and located further apically than on adjacent teeth
• the gingival margin is recessed apically to follow the bone, leading to exposure of the root
• the gingiva is bulbous on the lingual surface
• the bone margins are closer to the CEJ
Mention the characteristics of a thin periodontal biotype and how brushing or restorations serve as risk factors for gingival recession
Decreased width of keratinized tissue
• Reduced thickness of alveolar bone due to abnormal tooth position in the arch
• Studies have found poor toothbrushing habits to be potential risk factors for recession: hard pressure, hard bristles, duration of brushing
- Restorative crowns that go sub gingivally in a thin- biotype can increase gingival recession
- The apical extent of the restorative margin should ideally be a minimum of 2.5mm from alveolar crest to avoid violation of biologic width, leading to: gingival recession and bone loss
List the classifications for recession
- Class I: recession does not extend to the mucogingival junction and there is no tissue loss in the interproximal area
- Class II: recession extends to or beyond the mucogingival junction. There is no periodontal loss in the interproximal area
- Class III: recession extends to or beyond the mucogingival junction. Bone or soft tissue loss is present in the interdental area
- Class IV: recession extends to or beyond the mucogingival junction.
Consider impact of interproximal recession on clinical attachment
• CAL: measured from the CEJ to the base of the sulcus
Interproximal recession can increase CAL
Discuss treatment considerations for patients without recession for thick periodontal biotypes
Thick gingival biotype
• Prevention through good oral hygiene instruction and monitoring of the case