Periodontology at a Glance

Valerie Clerehugh, Aradhna Tugnait, Robert J. Genco

• Publisher: Wiley-Blackwell
• Year: 2013
• Print ISBN: 9781405123839
• eBook ISBN: 9781118691335
• Edition: 1
• Topic: Medicine
• Subtopic: Dentistry

Periodontology at a Glance
Valerie Clerehugh, Aradhna Tugnait and Robert J. Genco

Periodontology at a Glance adds another dentistry title to this popular series. It provides readers with an easy-to-use tool to assimilate the key information about periodontics by illustrating each topic with a double-page spread that encapsulates essential knowledge.??Clear diagrams and clinical pictures are accompanied by succinct text, providing a highly visual format to facilitate ease of learning. Suggestions for further reading are provided selectively where appropriate, and the authors present a useful distillation of the salient research literature.

Structured over 43 topics, Periodontology at a Glance covers:

• Anatomy of the periodontium
• Aetiology, diagnosis and classification of periodontal diseases
• Surgical and non-surgical therapies
• Patient management
• Risk factors, including systemic disease

Periodontology at a Glance provides a brief but comprehensive overview of periodontology. It will be a popular and useful resource for dentistry students, qualified dentists seeking a refresher, and other dental professionals.

1

Anatomy of the periodontium

Figure 1.1 Longitudinal section through part of a tooth showing healthy periodontal tissues.

Figure 1.2 Dentogingival fibres, alveolar crest fibres and circular fibres in the gingival connective tissue.

Figure 1.3 Interdental area showing transeptal and circular fibre groups in the gingival connective tissue.

Figure 1.4 The periodontal ligament.

Figure 1.5 Bony fenestration and dehiscence.

The periodontal tissues form the supporting structures of the teeth. The principal components of the periodontium are shown in Fig. 1.1:

• Gingivae (including epithelium and connective tissue).

• Periodontal ligament.

• Cementum.

• Alveolar bone.

Gingivae

The gingivae in health are pink and firm with a knife-edge appearance, scalloped around the teeth. In certain ethnic groups the gingivae may be pigmented. In health, the gingival margin is a few millimetres coronal to the cement–enamel junction. The gingival sulcus (or crevice) is a shallow groove which may be between 0.5 and 3 mm in depth around a fully erupted tooth. The gingival tissues are keratinised and appear paler pink than sites of non-keratinised oral epithelium.

Gingival epithelium

The gingival epithelium comprises (Fig. 1.1):

• Oral epithelium (OE).

• Oral sulcular epithelium (SE).

• Junctional epithelium (JE).

The gingival sulcus is lined by SE and JE.

Oral epithelium

• The OE is an orthokeratinised, stratified, squamous epithelium.

• Surface cells lose their nuclei and are packed with the protein keratin.

• It presents an impermeable physical barrier to oral bacteria.

The basal layer of epithelial cells is thrown up into folds overlying the supporting connective tissue. These folds increase the surface area of contact between the epithelium and connective tissue and are known as rete ridges or rete pegs.

Oral sulcular epithelium

• There are no rete ridges.

• Cells are keratinised but still have nuclei (parakeratinised).

Junctional epithelium

• The JE forms a specialised attachment to the tooth via:

• a hemidesmosomal layer within the JE cells;

• a basal lamina produced by the epithelial cells.

• The JE is non-keratinised and has a very fast turnover of cells (2–6 days compared to 1 month for OE).

• The most apical part of the JE lies at the cement-enamel junction in health.

• The JE at its widest point is 20–30 cells thick coronally.

• The JE tapers until it is only one cell in width apically.

• The JE is permeable with wide intercellular spaces through which cells and substances can migrate (such as bacterial toxins or host defence cells).

• Migration of the JE from its position in health apically onto the root cementum indicates a loss of periodontal attachment and progression to the disease state of periodontitis.

Gingival connective tissue

The gingival connective tissue (or lamina propria) is made up of collagen fibre bundles called gingival fibres, around which lie ground substance, fibroblasts, blood and lymph vessels and neural tissues. The four fibre groups are shown in Figs 1.2 and 1.3.

Periodontal ligament

The periodontal ligament forms the attachment between the cementum and alveolar bone. It is a richly vascular connective tissue within which lie bundles of collagen fibres; these are divided into four groups based on their position (Fig. 1.4).

Within the ligament are mechanoreceptors that provide sensory input for jaw reflexes. Cells from the periodontal ligament are involved in the formation and remodelling of alveolar bone and cementum. The periodontal ligament acts to dissipate masticatory forces to the supporting alveolar bone and its width, height and quality determine a tooth’s mobility.

Cementum

Cementum is a mineralised tissue overlying the root dentine. It does not undergo physiological remodelling but is continuously deposited throughout life. Cementum is classified into two types:

• Acellular.

• Cellular.

Acellular cementum

Acellular cementum forms on root dentine during root formation and tooth eruption. Fibres inserted from the periodontal ligament are mineralised within the cementum and are known as Sharpey’s fibres and are abundant in acellular cementum.

Cellular cementum

Cellular cementum lies over the acellular cementum. It contains cells called cementocytes which lie in lacunae. The cellular cementum layer is thicker in the apical region of the root where it is between 0.2 and 1 mm thick.

Alveolar bone

• The walls of the sockets are lined with a layer of dense bone called compact bone, which also forms the buccal and lingual/palatal plates of the jaw bones.

• In between the sockets and the compact jaw bone walls lies cancellous bone that is made up of bony trabeculae.

• The compact bone ...

Table of contents

• Cover
• Contents
• Title
• Copyright
• Preface
• Acknowledgements and Dedications
• 1: Anatomy of the Periodontium
• 2: Classification of Periodontal Diseases
• 3: Periodontal Epidemiology
• 4: Role of Plaque in the Aetiology of Periodontal Diseases
• 5: Plaque Microbiology
• 6: Calculus
• 7: Host Defences
• 8: Development of Periodontal Diseases
• 9: Progression of Periodontal Diseases
• 10: Risk and Periodontal Diseases
• 11: Systemic Risk Factors for Periodontal Diseases
• 12: Periodontal Diseases and General Health
• 13: Diet and Periodontal Diseases
• 14: Local Risk Factors for Periodontal Diseases
• 15: Occlusion and Periodontal Diseases
• 16: Periodontal History, Examination and Diagnosis
• 17: Periodontal Screening
• 18: Role of Radiographs in Periodontal Diagnosis
• 19: Principles of Periodontal Diagnosis and Treatment Planning
• 20: Plaque Control and Non-surgical Periodontal Therapy
• 21: Patient Communication in Dental Care
• 22: Periodontal Tissue Response, Healing and Monitoring
• 23: Role of Antimicrobial Therapy in Periodontal Diseases
• 24: Periodontal surgery
• 25: Types of Periodontal Surgery
• 26: Regenerative Periodontal Therapy
• 27: Bone Defects and Furcation Lesions
• 28: Dental Implants and Peri-Implantology
• 29: Periodontic–orthodontic Interface
• 30: Plaque-Induced Gingivitis
• 31: Non-Plaque-Induced Gingival Conditions and Lesions
• 32: Gingival Recession
• 33: Gingival Overgrowth
• 34: Chronic Periodontitis
• 35: Aggressive Periodontitis
• 36: Periodontal Management of Patients Who Smoke
• 37: Periodontal Management of Patients with Diabetes
• 38: Necrotising Periodontal Diseases
• 39: Periodontal Abscess and Periodontic–endodontic Lesions
• 40: Periodontal Diseases in Children and Adolescents
• 41: Periodontal Management of the Older Adult
• 42: Team Working in Dental Care
• 43: The Decision to Treat or Refer Periodontal Patients
• Appendix: References and Further Reading
• Index