Image OCR:
Extracting all text from this PDF page image. Use the PDF text for context to enhance accuracy. Prioritize image text but use PDF text to resolve ambiguities. If the text is in a different colour, format it as bold. Errors may occur with the pdf text — if it is obviously corrupted or error-ridden then ignore it.
FORMAT RULES:
- Format tables in HTML (only tables, NOTHING ELSE).
- Format flowcharts as tables as best as possible.
- All other formatting must be in Markdown.
FIGURE/IMAGE RULES (CRITICAL):
- If a figure is an image with only labels or sparse text, output ONLY a brief 2-5 word description wrapped in tags. Example:
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- NEVER output image descriptions as plain text outside of tags.
- NEVER output standard HTML image tags like <img src="...">.
- NEVER output <div>, <figure>, <section>, or other HTML wrapper tags (except tables).
- NEVER explain your reasoning, reference the instructions, or include meta-commentary. Output ONLY the OCR text and/or descriptions.
DO NOT ADD ANYTHING TO THE TEXT ITSELF. YOU ARE ONLY TRANSCRIBING/FORMATTING. DO NOT SAY ANYTHING ELSE.
<Dental impression procedure>
![]()
Clinical photo showing two exposed tooth stumps with silver amalgam cores and a blue impression material tray positioned nearby.
**The University of Western Australia** | **Oral Health Centre of Western Australia**
**Learning Outcomes:**
1. Define the objectives of definitive impressions.
2. Discuss the impact of subgingival margins on the soft tissue management.
3. Define the aims of gingival displacement and describe the different methods of gingival displacement.
4. Discuss the importance of impression timing
5. Describe the ideal impression.
Upon completion of this section, you should be able to:
1. Define the objectives of definitive impressions.
2. Discuss the impact of subgingival margins on the soft tissue management.
3. Define the aims of gingival displacement and describe the different methods of gingival displacement.
4. Discuss the importance of impression timing.
5. Describe the ideal impression.
![]()
Institutional logos for The University of Western Australia and the Oral Health Centre of Western Australia. These serve as visual identifiers for the academic context of the slide.
# Impression
Restorations which fit exactly and can be inserted without any further corrections
**Exact fitting restorations**:
* More efficient and faster working
* Aid periodontal prophylaxis, caries
* Aesthetic results
* Prognosis
### Table 2. Periradicular status for various combinations of treatment quality:
| Group | Endo | Coronal | No. teeth | PPI | API | %API |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | Good (GE) | Good (GR) | 330.5 | 28.5 | 302.0 | 91.4 |
| 2 | Good (GE) | Poor (PR) | 164.5 | 92.0 | 72.5 | 44.1 |
| 3 | Poor (PE) | Good (GR) | 302.5 | 98.0 | 204.5 | 67.6 |
| 4 | Poor (PE) | Poor (PR) | 188.0 | 154.0 | 34.0 | 18.1 |
PPI, presence of periradicular inflammation.
API, absence of periradicular inflammation.
**Ray HA, Trope M. 1995**
### Table 3. Success rate of endodontic treatment of good or poor quality in teeth with good or poor coronal restorations
| Endodontic treatment | Coronal restoration | n | Failure | Success | Success in percent |
| :--- | :--- | :--- | :--- | :--- | :--- |
| GE | GR | 364 | 70 | 294 | 81%* |
| GE | PR | 142 | 41 | 101 | 71%* |
| PE | GR | 299 | 131 | 168 | 56%* |
| PE | PR | 196 | 85 | 111 | 57%* |
GE=Good Endodontics; PE=Poor Endodontics; GR=Good Restoration; PR=Poor Restoration.
* The difference between the success rate with Good Endodontics and Poor Endodontics was statistically significant ($P<0.0001$) regardless of the quality of the coronal restoration (GR or PR).
**Tronstad L, Asbjørnsen K, Døving L, Pedersen I, Eriksen HM. 2000**
Restorations which fit exactly and can be inserted without any further corrections provide several clinical benefits:
- More efficient and faster working
- Aid periodontal prophylaxis and caries prevention
- Aesthetic results
- Improved prognosis
#### Impact of Treatment Quality on Periradicular Status
| Group | Endo | Coronal | No. teeth | PPI | API | %API |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | Good (GE) | Good (GR) | 330.5 | 28.5 | 302.0 | 91.4 |
| 2 | Good (GE) | Poor (PR) | 164.5 | 92.0 | 72.5 | 44.1 |
| 3 | Poor (PE) | Good (GR) | 302.5 | 98.0 | 204.5 | 67.6 |
| 4 | Poor (PE) | Poor (PR) | 188.0 | 154.0 | 34.0 | 18.1 |
*PPI: presence of periradicular inflammation; API: absence of periradicular inflammation (Ray and Trope, 1995).*
#### Success Rates of Endodontic and Coronal Treatment
| Endodontic treatment | Coronal restoration | n | Failure | Success | Success in percent |
| :--- | :--- | :--- | :--- | :--- | :--- |
| GE | GR | 364 | 70 | 294 | 81%* |
| GE | PR | 142 | 41 | 101 | 71%* |
| PE | GR | 299 | 131 | 168 | 56%* |
| PE | PR | 196 | 85 | 111 | 57%* |
*GE: Good Endodontics; PE: Poor Endodontics; GR: Good Restoration; PR: Poor Restoration. The difference between success rates with Good vs. Poor Endodontics was statistically significant (P<0.0001) regardless of coronal restoration quality (Tronstad et al., 2000).*
![]()
Table 2: Periradicular status for various combinations of treatment quality. Columns include Group, Endo (Good/Poor), Coronal (Good/Poor), No. teeth, PPI (presence of periradicular inflammation), API (absence of periradicular inflammation), and %API. Rows show data for four groups combining good/poor endodontic and coronal treatments, with corresponding statistics. Source cited as Ray HA, Trope M. 1995.
![]()
Table 3: Success rate of endodontic treatment of good or poor quality in teeth with good or poor coronal restorations. Columns include Endodontic treatment (GE/PE), Coronal restoration (GR/PR), n (sample size), Failure count, Success count, and Success in percent. Data shows success rates ranging from 56% to 81%. Includes footnote indicating statistical significance (P<0.0001). Source cited as Tronstad L et al. 2000.
**Impression**
**Impression Objectives:**
1. Exact duplication of the prepared and uncut tooth beyond the preparation to allow evaluation of location and configuration of finishing line
2. Duplicate other teeth and soft tissue to permit proper articulation of the cast and contouring the restoration
3. Must be free of bubbles specially at finishing line and prepared surfaces
The primary goals for a definitive impression include:
1. Exact duplication of the prepared and uncut tooth beyond the preparation to allow evaluation of location and configuration of the finishing line.
2. Duplication of other teeth and soft tissue to permit proper articulation of the cast and contouring of the restoration.
3. Ensuring the impression is free of bubbles, especially at the finishing line and prepared surfaces.
![]()
Line drawing of a tooth with a red curved line indicating the finishing line or preparation margin. The diagram is used to visually demonstrate the concept of 'finishing line' mentioned in the OCR text.
**Impression**
<br>
**Aim of impression:** produce a dimensionally stable “negative”
▪ Mould for an analogue model
<br>
▪ Scanned with CAD/CAM model
## Milled Model ##
## 3D Printed Model ##
The aim of an impression is to produce a dimensionally stable “negative” which serves as:
- A mould for an analogue model.
- A source to be scanned for a CAD/CAM model, resulting in a Milled Model or 3D Printed Model.
![]()
Clinical photo of an analogue dental cast (mould) showing a lower jaw model with teeth and a tooth-colored restoration on the left side. The text 'Mould for an analogue model' is associated with this image.
![]()
Photo of a 3D printed dental model production device (likely stereolithography or DLP printer) with an orange protective cover and visible resin vat. Associated with the text '3D Printed Model'.
![]()
Photo of a CAD/CAM milling machine used to produce milled models from digital scans. The machine is white/grey with a control panel screen. Associated with the text 'Milled Model'.
![]()
Clinical photo of a blue CAD/CAM milled dental model showing upper and lower arches with a tooth-colored restoration. The model includes mounting attachments. Associated with the text 'Scanned with CAD/CAM model'.
![]()
Flowchart diagram illustrating the workflow of dental restoration processes. The diagram starts with 'Preparation' at the top and branches into two main pathways: 'Conventional' on the left and 'CAD-CAM' on the right. Each pathway includes sequential steps indicated by arrows and labeled boxes (e.g., 'Impression', 'Fabrication of models', 'Casting', 'Manual finishing', etc.). The diagram also includes logos for 'The University of Western Australia' and 'Oral Health Centre of Western Australia' in the top right corner.
<table border="1" cellspacing="0">
<tr>
<td colspan="7" align="right"><b>THE UNIVERSITY OF WESTERN AUSTRALIA</b> | <b>Oral Health Centre of Western Australia</b></td>
</tr>
<tr>
<td colspan="7" align="center"><b>Preparation</b></td>
</tr>
<tr>
<td colspan="7"><b>Impression</b></td>
</tr>
<tr>
<td colspan="7">Conventional</td>
</tr>
<tr>
<td colspan="4">Fabrication of models</td>
<td colspan="3">CAD-CAM</td>
</tr>
<tr>
<td colspan="4">Scanning<br/>Casting</td>
<td colspan="3">Milling<br/>Scanning</td>
</tr>
<tr>
<td colspan="4">Manual finishing</td>
<td colspan="3">Veneering/Polishing</td>
</tr>
<tr>
<td colspan="4">Insert</td>
<td colspan="3">Insert</td>
</tr>
</table>
#### Workflow Comparison
- **Conventional Workflow**
- Preparation
- Impression
- Fabrication of models (Casting)
- Manual finishing
- Insertion
- **Digital Workflow (CAD-CAM)**
- Preparation
- Impression
- Scanning
- Milling
- Veneering/Polishing
- Insertion
![]()
A flowchart comparing two dental restoration fabrication pathways: 'Conventional' and 'CAD-CAM'. The Conventional path branches from 'Fabrication of models' to 'Scanning', 'Casting', 'Manual finishing', 'Veneering/Polishing', and ends at 'Insert'. The CAD-CAM path shows a sequence from 'Scanning' (linked back from the main diagram) to 'Milling', 'Sintering', 'Veneering/Polishing', and 'Insert'. Red arrows indicate process flow between steps.
| | |
| :--- | :--- |
| Preparation |
| Impression | Scanning |
| **Conventional** | CAD-CAM |
| Fabrication of models | Scanning |
| Casting | Milling |
| Manual finishing | Sintering |
| Veneering/Polishing | Veneering/Polishing |
| Insert | Insert |
#### Integrated Workflow Steps
1. **Preparation**
2. **Impression / Scanning**
3. **Fabrication**
- Conventional: Casting and Manual finishing
- CAD-CAM: Milling and Sintering
4. **Finishing**: Veneering/Polishing
5. **Insertion**
![]()
Flowchart diagram comparing 'Conventional' and 'CAD-CAM' dental fabrication workflows. The chart begins with 'Preparation', leading to either 'Impression' (for the Conventional path) or 'Scanning' (for the CAD-CAM path). The Conventional branch details steps including 'Fabrication of models', 'Casting', 'Manual finishing', 'Veneering/Polishing', and 'Insert'. The CAD-CAM branch shows a sequence of 'Scanning', 'Milling', 'Sintering', 'Veneering/Polishing', and 'Insert'. Red arrows indicate the flow of processes between these stages.
```mermaid
graph TD
Preparation --> Impression
Preparation --> Scanning
Impression --> Scanning
Impression --> Fabrication_of_models["Fabrication of models"]
subgraph Conventional
Fabrication_of_models --> Casting
Casting --> Manual_finishing["Manual finishing"]
Manual_finishing --> Veneering_Polishing["Veneering/Polishing"]
Veneering_Polishing --> Insert
end
subgraph CAD-CAM
Fabrication_of_models --> Scanning_2["Scanning"]
Scanning --> Milling
Scanning_2 --> Milling
Milling --> Sintering
Sintering --> Veneering_Polishing_2["Veneering/Polishing"]
Veneering_Polishing_2 --> Insert_2["Insert"]
end
```
#### Process Mapping
- **Conventional Path**: Preparation → Impression → Fabrication of models → Casting → Manual finishing → Veneering/Polishing → Insert.
- **CAD-CAM Path**: Preparation → Scanning (or Impression to Scanning) → Milling → Sintering → Veneering/Polishing → Insert.
![]()
Flowchart comparing 'Conventional' and 'CAD-CAM' dental restoration procedures. The diagram starts with 'Preparation', which branches into two main paths: the 'Conventional' path on the left (Casting -> Manual finishing -> Veneering/Polishing -> Insert) and the 'CAD-CAM' path on the right (Scanning -> Milling -> Sintering -> Veneering/Polishing -> Insert). A central column shows 'Impression' leading to 'Fabrication of models', which then connects to both subsequent workflows. Red arrows indicate process flow.
```mermaid
graph TD
Preparation --> Impression
Preparation --> Scanning
Impression --> Fabrication_of_models
Impression --> Scanning
subgraph Conventional
Fabrication_of_models --> Casting
Casting --> Manual_finishing
Manual_finishing --> Veneering/Polishing_Conv[Veneering/Polishing]
Veneering/Polishing_Conv --> Insert_Conv[Insert]
end
subgraph CAD-CAM
Fabrication_of_models --> Scanning_2[Scanning]
Scanning --> Milling
Scanning_2 --> Milling
Milling --> Sintering
Sintering --> Veneering/Polishing_CAD[Veneering/Polishing]
Veneering/Polishing_CAD --> Insert_CAD[Insert]
end
```
#### Workflow Logic
- **Data Acquisition**: Can occur via direct Scanning or via an Impression followed by Scanning of the model.
- **Production**:
- Conventional: Casting and manual finishing.
- CAD-CAM: Milling and sintering.
![]()
Flowchart comparing 'Conventional' and 'CAD-CAM' dental fabrication workflows. The diagram starts with a 'Preparation' box at the top, branching into two main paths: 'Conventional' on the left and 'CAD-CAM' on the right. Each path includes sequential steps represented by boxes connected by arrows. The 'Conventional' path includes 'Impression', 'Fabrication of models', 'Casting', 'Manual finishing', 'Veneering/Polishing', and 'Insert'. The 'CAD-CAM' path includes 'Scanning', 'Milling', 'Sintering', 'Veneering/Polishing', and 'Insert'. Logos for 'The University of Western Australia' and 'Oral Health Centre of Western Australia' are present in the top-right corner.
```mermaid
graph TD
Workflow([Workflow]) --> Preparation
Preparation --> Impression
Preparation --> Scanning
subgraph Conventional
Impression --> Fabrication_of_models[Fabrication of models]
Fabrication_of_models --> Casting
Casting --> Manual_finishing[Manual finishing]
Manual_finishing --> Veneering_Polishing_C[Veneering/Polishing]
Veneering_Polishing_C --> Insert_C[Insert]
end
subgraph CAD_CAM[CAD-CAM]
Scanning --> Milling
Impression --> Scanning
Fabrication_of_models --> Scanning_M[Scanning]
Scanning_M --> Milling
Milling --> Sintering
Sintering --> Veneering_Polishing_CAD[Veneering/Polishing]
Veneering_Polishing_CAD --> Insert_CAD[Insert]
end
```
#### Comprehensive Workflow Overview
- **Preparation Phase**: Initial tooth preparation.
- **Impression/Scanning Phase**: Capturing the clinical situation.
- **Conventional Fabrication**: Model fabrication, casting, and manual finishing.
- **CAD-CAM Fabrication**: Digital scanning of models or direct scans, milling, and sintering.
![]()
Flowchart comparing two dental workflow processes: Conventional and CAD-CAM. The diagram begins with 'Preparation' at the top center, which branches into two distinct pathways. The left pathway, labeled 'Conventional', proceeds through 'Impression', 'Fabrication of models', 'Casting', 'Manual finishing', 'Veneering/Polishing', and ends at 'Insert'. The right pathway, labeled 'CAD-CAM', starts with 'Scanning' (receiving input from both Preparation and Impression), followed by 'Milling', 'Sintering', 'Veneering/Polishing', and concludes at 'Insert'. Red arrows indicate the flow between steps.
# Impressions
## Impression/Scanning Prerequisites
* **Tissue management**
* **Gingival tissue displacement (if needed)**
* **Saliva control**
* **Adequate impression/scanning technique**
To achieve a successful impression or scan, the following must be managed:
- Tissue management
- Gingival tissue displacement (if needed)
- Saliva control
- Adequate impression/scanning technique
![]()
Clinical photo demonstrating tissue management and gingival displacement. A close-up view shows a patient's mouth with a green dental retractor in place to displace the cheek/gingiva, exposing the teeth for an impression procedure.
![]()
Procedure image illustrating adequate scanning technique. A dental professional uses an intraoral scanner on a patient while a digital 3D model of the dentition is displayed on monitors in the background.
**Tissue management**
- **Careful preparation**
- Hard tissue
- Soft tissue
- Atraumatic procedure
- Well-contoured provisional restoration
- Adequate oral hygiene
#### Clinical Management Strategies
- **Careful Preparation**:
- Hard tissue
- Soft tissue
- Atraumatic procedure
- Well-contoured provisional restoration
- Adequate oral hygiene
## Tissue management
## Tooth Preparation
* Supragingival margins if possible
* Minimally subgingival or intra-crevicular
* Well-defined, smooth and continuous margins
* Well-finished and tidy preparation
* Atraumatic to gingival tissues
The University of Western Australia Oral Health Centre of Western Australia
THE UNIVERSITY OF WESTERN AUSTRALIA
#### Preparation Guidelines
- Supragingival margins if possible.
- Minimally subgingival or intra-crevicular.
- Well-defined, smooth, and continuous margins.
- Well-finished and tidy preparation.
- Atraumatic to gingival tissues.
**Tissue management - supragingival preparation**
A
Supragingival preparation
![]()
Clinical photo showing a supragingival preparation on anterior teeth. The image displays the upper front teeth with visible gingival margins and tooth surfaces.
![]()
Clinical photo labeled 'A' showing another view of supragingival preparation on anterior teeth. The image highlights the gingival tissue and prepared tooth surfaces.
![]()
Clinical photo showing a close-up view of supragingival preparation on posterior teeth. The image focuses on the prepared tooth surfaces and surrounding gingival tissue.
1. DGC – Dentogingival Complex & Biologic Width
2. Connective tissue 1.07 mm
3. Junctional epithelium 0.97 mm
4. Gingival sulcus 0.5-1 mm
5. Biologic Width 2 - 2.25 mm
6. **Margin location**
► If the margins has to be subgingival it should only be placed intracrevicularly
► Maximum depth around 0.7mm
<vm>Margin location showing subgingival placement guidelines for dental margins.
1. DGC – Dentogingival Complex & Biologic Width
2. Connective tissue 1.07 mm
3. Junctional epithelium 0.97 mm
4. Gingival sulcus 0.5-1 mm
5. Biologic Width 2 - 2.25 mm
6. **Margin location**
► If the margins has to be subgingival it should only be placed intracrevicularly
► Maximum depth around 0.7mm
<vm>Margin location showing subgingival placement guidelines for dental margins.
![]()
Labelled anatomical diagram of the Dentogingival Complex (DGC). The illustration shows a cross-section of a tooth and gum with callouts identifying specific tissue layers and dimensions: 'Connective tissue 1.07 mm', 'Junctional epithelium 0.97 mm', and 'Gingival sulcus 0.5-1 mm'. A blue box highlights the combined area labeled as 'Biologic Width 2 - 2.25 mm'.
Biologic Width Violation
Biologic Width Violation
![]()
Clinical photo showing a close-up view of the maxillary central incisors and surrounding gingiva. The image illustrates a 'Biologic Width Violation' as indicated by the slide title. Visually, the gingival tissue between the two central incisors appears swollen, inflamed (erythematous), and bulbous, indicating an active inflammatory response to the restoration margin encroaching on the biologic width.
**Periodontal tissues**
**Preparation**
Periodontal tissues show more signs of inflammation around crowns with subgingival margins than those with supragingival
**Causes**
Defective margins
Inaccurate fit
Roughness of the tooth–restoration interface
Improper crown contour
Violation of the connective tissue attachment
Greater pathogenicity of the subgingival dental plaque
Material?
**Periodontal tissues**
**Preparation**
Periodontal tissues show more signs of inflammation around crowns with subgingival margins than those with supragingival
**Causes**
Defective margins
Inaccurate fit
Roughness of the tooth–restoration interface
Improper crown contour
Violation of the connective tissue attachment
Greater pathogenicity of the subgingival dental plaque
Material?
![]()
A clinical photograph demonstrating inflammation of periodontal tissues around dental crowns. The image is split into two panels: the top panel shows a close-up view of inflamed gingival tissue and teeth, illustrating the condition described in the text as signs of inflammation around crowns with subgingival margins. The bottom panel provides a closer view of the gum line where a periodontal probe is inserted, highlighting the pocket depth and tissue recession associated with the pathology.
“sounding the bone”
<table>
<thead>
<tr>
<th>Normal Crest</th>
<th>High Crest</th>
<th>Low Crest</th>
</tr>
</thead>
<tbody>
<tr>
<td>3 mm (4 approx)</td>
<td>&lt; 3 mm (4 approx)</td>
<td>&gt; 3 mm (4 approx)</td>
</tr>
</tbody>
</table>
Want to know more about biologic width? Read:
Mulla SA, Patil A, Mali S, Jain A, Sharma D, Jaiswal HC, Saoji HA, Jakhar A, Talekar S, Singh S. Exploring the Biological Width in Dentistry: A Comprehensive Narrative Review. Cureus. 2023 Jul 18;15(7).
“sounding the bone”
<table>
<thead>
<tr>
<th>Normal Crest</th>
<th>High Crest</th>
<th>Low Crest</th>
</tr>
</thead>
<tbody>
<tr>
<td>3 mm (4 approx)</td>
<td>&lt; 3 mm (4 approx)</td>
<td>&gt; 3 mm (4 approx)</td>
</tr>
</tbody>
</table>
Want to know more about biologic width? Read:
Mulla SA, Patil A, Mali S, Jain A, Sharma D, Jaiswal HC, Saoji HA, Jakhar A, Talekar S, Singh S. Exploring the Biological Width in Dentistry: A Comprehensive Narrative Review. Cureus. 2023 Jul 18;15(7).
![]()
Labelled figure demonstrating 'sounding the bone' to assess biologic width. The visual is a composite of four anatomical cross-sections showing tooth roots (yellow), gingiva (pink/red), and alveolar bone (white). A grey instrument tip is shown in three panels probing the junction between the gingiva and bone. Labels below each panel categorize the findings: Normal Crest at 3 mm, High Crest < 3 mm, and Low Crest > 3 mm.
**Normal Crest – Preparation & Tissue Management**
**Normal Crest – Preparation & Tissue Management**
![]()
A sequence of seven labeled diagrams illustrating the 'Normal Crest – Preparation & Tissue Management' process. The images show a cross-section of dental anatomy (tooth root and gum tissue) with instruments or materials being applied in steps to manage the tissue around the crest.
**Tissue Management – double cord**
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
---
THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia
**Tissue Management – double cord**
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
---
THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia
![]()
Clinical photo showing a close-up view of anterior teeth with the gingival tissue in a pre-procedure state. The central incisor exhibits significant recession and a short clinical crown length.
![]()
Clinical photo showing the same tooth area post-procedure. A double cord technique has been applied, evidenced by the retracted gingiva exposing the tooth margin and a visible blue-colored hemostatic agent or material at the sulcus level.
## Impression
| Category | Description |
| :--- | :--- |
| **Image Description** | |
Impression
| Category | Description |
| :--- | :--- |
| **Image Description** | |
![]()
Clinical photo of an impression showing the emergence profile. The image displays a tooth preparation or crown margin in blue dental material (likely silicone or polyvinyl siloxane) with a central lighter area representing the prepared tooth structure.
# **Gingival Displacement**
## Aims
* Enlargement of gingival sulcus
* Tissue deflection horizontally and vertically to display the margin and root surface
* Finishing line for the restoration
* Development of adequate emergence profile
* Control of gingival bleeding and exudate
**Gingival Displacement**
Aims
* Enlargement of gingival sulcus
* Tissue deflection horizontally and vertically to display the margin and root surface
* Finishing line for the restoration
* Development of adequate emergence profile
* Control of gingival bleeding and exudate
## Gingival Displacement Methods
### Mechanical Displacement
* Retraction cord
* Copper band
### Chemicals
* Astringent: aluminium chloride
* Astringent: ferric sulfate
* Adrenaline - transient ischemia and epithelial tissue shrinkage
### Combined
* Retraction cord + chemical
* Expasyl (Kerr)
### Surgical widening
* Electrosurgery
* Laser
Gingival Displacement Methods
### Mechanical Displacement
* Retraction cord
* Copper band
### Chemicals
* Astringent: aluminium chloride
* Astringent: ferric sulfate
* Adrenaline - transient ischemia and epithelial tissue shrinkage
### Combined
* Retraction cord + chemical
* Expasyl (Kerr)
### Surgical widening
* Electrosurgery
* Laser
![]()
A composite clinical photograph series demonstrating the step-by-step procedure for gingival displacement using a retraction cord. The sequence includes: (1) showing the tooth and prepared cavity; (2) placing a copper band on the tooth; (3) inserting the cord into the periodontal space with an instrument; (4) packing the cord further with a tool; (5) a close-up of the cord material; (6) manipulating the cord with pliers; (7) the cord packed against the gumline; (8) removal of the cord; (9) the removed copper band; (10) the exposed preparation after cord removal; (11) a different angle of the exposed preparation; (12) applying a matrix band or similar device to the preparation; (13) the matrix band in place; and (14) a final view of the prepared area.
Mechanical Displacement: **Retraction cord**
Cord is packed into sulcus stretching the circumferential periodontal fibers 0.3-0.4 mm
**Types:**
• Braided
• Knitted
• Twisted
• Medicated and nonmedicated
Mechanical Displacement: **Retraction cord**
Cord is packed into sulcus stretching the circumferential periodontal fibers 0.3-0.4 mm
**Types:**
• Braided
• Knitted
• Twisted
• Medicated and nonmedicated
![]()
Visual comparison of three retraction cord types: top shows a braided texture (purple), middle shows a knitted loop pattern (blue), and bottom shows a twisted strand structure (grey). These visuals correspond to the listed 'Types' in the OCR text.
# Retraction cord
Text from logo: the university of **WESTERN** **AUSTRALIA** Oral Health centre of Western Australia
Retraction cord
Text from logo: the university of **WESTERN** **AUSTRALIA** Oral Health centre of Western Australia
![]()
Clinical photo showing six different sizes of dental retraction cord containers (labeled #000, #00, #0, #1, #2, and #3) lined up against a black background. The image is part of a slide titled 'Retraction cord' from the University of Western Australia Oral Health Centre.
Cord Packer
Serrated
Non-serrated
Cord Packer
Serrated
Non-serrated
![]()
Close-up photograph of a dental instrument labeled 'Serrated', showing the serrated edge on the tip used for packing material.
![]()
Close-up photograph of a dental instrument labeled 'Non-serrated', showing a smooth, rounded tip designed for packing material without cutting edges.
# Retraction cord displacement
Retraction cord displacement
![]()
Clinical photo showing a tooth with a silver amalgam restoration. A green retraction cord is placed around the gingival margin to displace the gum tissue, exposing the finish line of the crown preparation.
![]()
Clinical photo showing the same tooth after the retraction cord has been removed. The gingival tissue has returned to its natural position around the silver amalgam restoration.
Cord Packing technique
**Vertical**
**Rotational**
Oral Health Centre
of Western Australia
THE UNIVERSITY
OF WESTERN
AUSTRALIA
Cord Packing technique
**Vertical**
**Rotational**
Oral Health Centre
of Western Australia
THE UNIVERSITY
OF WESTERN
AUSTRALIA
![]()
Illustration of the 'Vertical' cord packing technique. Top inset shows a diagrammatic view with an instrument pushing material downwards into the sulcus (indicated by purple arrows). Main image shows a clinical view of a tooth where a dental probe is used to vertically pack blue periodontal cord material into the gingival sulcus.
![]()
Illustration of the 'Rotational' cord packing technique. Top inset shows a diagrammatic view with numbered steps (1 and 2) indicating a twisting or rotational motion of the instrument. Main image shows a clinical view of a tooth where a dental probe is used in a rotational manner to pack blue periodontal cord material into the gingival sulcus.
Retraction cords
**Fig 16-13** A loop of retraction cord is formed around the tooth and held tautly with the thumb and forefinger.
**Fig 16-14** (a) Placement of the retraction cord is begun by pushing it into the sulcus on the mesial surface of the tooth. (b) It should also be tacked lightly into the distal crevice to hold the cord in position while it is being placed.
Retraction cords
**Fig 16-13** A loop of retraction cord is formed around the tooth and held tautly with the thumb and forefinger.
**Fig 16-14** (a) Placement of the retraction cord is begun by pushing it into the sulcus on the mesial surface of the tooth. (b) It should also be tacked lightly into the distal crevice to hold the cord in position while it is being placed.
![]()
Fig 16-13: A clinical procedure diagram showing a loop of retraction cord formed around a tooth and held tautly with the thumb and forefinger.
![]()
Fig 16-14: (a) Placement of the retraction cord is begun by pushing it into the sulcus on the mesial surface of the tooth. (b) It should also be tacked lightly into the distal crevice to hold the cord in position while it is being placed.
**Mechanical Displacement: Retraction cord**
Single cord
Double cord
Leave the cords in place
three to five minutes
**Mechanical Displacement: Retraction cord**
Single cord
Double cord
Leave the cords in place
three to five minutes
![]()
Labelled figure demonstrating mechanical displacement using retraction cords. The visual is split into two panels: the left panel shows a 'Single cord' application where one green cord is wrapped around the gingiva on both sides of a tooth; the right panel shows a 'Double cord' application with two green cords stacked vertically. Both illustrations depict the cords placed against the gum line to retract soft tissue.
**Mechanical Displacement: Retraction cord**
Single cord
Double cord
**1st cord: vertical retraction**
**2nd cord: Horizontal displacement**
GRACIS et al. 2001
**Mechanical Displacement: Retraction cord**
Single cord
Double cord
**1st cord: vertical retraction**
**2nd cord: Horizontal displacement**
GRACIS et al. 2001
![]()
Clinical photos under 'Single cord' section showing two views of teeth with a retraction cord placed. Top image shows the initial placement; bottom image shows the result after vertical retraction.
![]()
Procedural images under 'Double cord' section demonstrating two-step retraction technique. Top image labeled '1st cord: vertical retraction' shows first cord placement. Bottom image labeled '2nd cord: Horizontal displacement' shows second cord placement for horizontal movement.
# Mechanical Displacement: Retraction cord
**The University of Western Australia** | **Oral Health Centre of Western Australia**
# Single cord
**Indication:**
* Shallow sulcus
* Thin periodontium
**Advantages:**
* Least traumatic
* Limited risk for gingival recession
**Disadvantages:**
* Haemorrhage
* Exudate
Mechanical Displacement: Retraction cord
**The University of Western Australia** | **Oral Health Centre of Western Australia**
Single cord
**Indication:**
* Shallow sulcus
* Thin periodontium
**Advantages:**
* Least traumatic
* Limited risk for gingival recession
**Disadvantages:**
* Haemorrhage
* Exudate
# Mechanical Displacement: Retraction cord
## Single cord
**Indication:**
* Shallow sulcus
* Thin periodontium
**Advantages:**
* Least traumatic
* Limited risk for gingival recession
**Disadvantages:**
* Haemorrhage
* Exudate
## Double cord
**Indication:**
* Thick periodontium
**Advantages:**
* Control of bleeding
* Excellent lateral displacement
**Disadvantages:**
* Time consuming
* Potentially traumatic
* Least predictable gingival response
Mechanical Displacement: Retraction cord
Single cord
**Indication:**
* Shallow sulcus
* Thin periodontium
**Advantages:**
* Least traumatic
* Limited risk for gingival recession
**Disadvantages:**
* Haemorrhage
* Exudate
Double cord
**Indication:**
* Thick periodontium
**Advantages:**
* Control of bleeding
* Excellent lateral displacement
**Disadvantages:**
* Time consuming
* Potentially traumatic
* Least predictable gingival response
# Chemical Displacement: Hemostatic agent
THE UNIVERSITY OF WESTERN AUSTRALIA | Oral Health Centre of Western Australia
## Metallic salts
* Causing transient ischemia
* Shrinkage of gingival tissues
* Reduce flow of gingival fluids
**Examples:**
* Aluminum chloride (*Hemadent*)
* Aluminum sulfate
* Potassium sulfate
* Ferric chloride
* Ferric sulfate (*Astringedent*)
## Adrenaline
* Can cause tachycardia
Chemical Displacement: Hemostatic agent
THE UNIVERSITY OF WESTERN AUSTRALIA | Oral Health Centre of Western Australia
Metallic salts
* Causing transient ischemia
* Shrinkage of gingival tissues
* Reduce flow of gingival fluids
**Examples:**
* Aluminum chloride (*Hemadent*)
* Aluminum sulfate
* Potassium sulfate
* Ferric chloride
* Ferric sulfate (*Astringedent*)
Adrenaline
* Can cause tachycardia
# Haemostasis - Expasyl
## Expasyl
Aluminium chloride with kaolin
Dispensed from a syringe
Expands on setting
Left for 1-2 minutes
Washed away with water spray
## Traxodent
Aluminium chloride paste
Procise The University of Western Australia
Oral Health Centre
of Western Australia
Haemostasis - Expasyl
Expasyl
Aluminium chloride with kaolin
Dispensed from a syringe
Expands on setting
Left for 1-2 minutes
Washed away with water spray
Traxodent
Aluminium chloride paste
Procise The University of Western Australia
Oral Health Centre
of Western Australia
![]()
Photo of the Expasyl dispensing tool, a white handheld device with a syringe mechanism labeled 'EXPASYL'. The text describes it as aluminium chloride with kaolin, dispensed from a syringe, expanding on setting, left for 1-2 minutes, and washed away with water spray.
![]()
Photo of the Traxodent product, showing a purple syringe applicator labeled 'Traxodent' held by a gloved hand, along with its packaging box. The text describes it as an aluminium chloride paste used for haemostasis.
Expasyl
THE UNIVERSITY OF
WESTERN
AUSTRALIA
Oral Health Centre
of Western Australia
Expasyl
THE UNIVERSITY OF
WESTERN
Oral Health Centre
of Western Australia
![]()
Clinical photo showing the upper dental arch with multiple teeth isolated by green Expasyl dam. Several teeth have restorations (fillings or crowns), and one tooth appears to have a temporary crown or filling material.
![]()
Close-up clinical photo of oral mucosa, likely gingival tissue, showing normal pink coloration and texture without visible pathology.
**Surgical widening**
Electrosurgery
**Advantages:**
* Lower cost than lasers.
* Electrosurgery cuts rapidly when compared to a diode laser.
* With proper intensity, immediate hemostasis.
* After cutting, the wound is nearly painless.
**Disadvantages:**
* Contraindicated in patients with any electrical device (PACEMAKERS!)
* You must anesthetize patients
* Burning smell
* Risk of overcutting
* Because of high heat production while cutting, electrosurgery should not be used around implants
**Surgical widening**
Electrosurgery
**Advantages:**
* Lower cost than lasers.
* Electrosurgery cuts rapidly when compared to a diode laser.
* With proper intensity, immediate hemostasis.
* After cutting, the wound is nearly painless.
**Disadvantages:**
* Contraindicated in patients with any electrical device (PACEMAKERS!)
* You must anesthetize patients
* Burning smell
* Risk of overcutting
* Because of high heat production while cutting, electrosurgery should not be used around implants
# Surgical Widening
## Laser
### Advantages:
* **Minimal** local anesthetic needed,
* **Does not harm** dental hard tissue.
* **Can be** used around **implants** (some **laser** produce heat)
* **Can be** used around full metal, PFM crowns, **amalgam** or **gold alloy** restorations.
### Disadvantages:
* Cost
* Cuts much slower than electrosurgery.
* Cutting large pieces of soft tissue is time consuming
* Danger of laser beam
Surgical Widening
Laser
### Advantages:
* **Minimal** local anesthetic needed,
* **Does not harm** dental hard tissue.
* **Can be** used around **implants** (some **laser** produce heat)
* **Can be** used around full metal, PFM crowns, **amalgam** or **gold alloy** restorations.
### Disadvantages:
* Cost
* Cuts much slower than electrosurgery.
* Cutting large pieces of soft tissue is time consuming
* Danger of laser beam
![]()
Institutional logo for The University of Western Australia and the Oral Health Centre of Western Australia.
**Saliva control**
Absorbents: block salivary ducts
▪ Cotton rolls
▪ Absorbing cards
Saliva evacuator
Local anesthesia: controls blood and saliva
**Saliva control**
Absorbents: block salivary ducts
▪ Cotton rolls
▪ Absorbing cards
Saliva evacuator
Local anesthesia: controls blood and saliva
![]()
Clinical photo showing black rubber dam frames and a dental procedure in progress with a white absorbent material placed between teeth to block salivary ducts.
![]()
Photo displaying a saliva evacuator (white plastic blade) being held by a patient's cheek, alongside multiple white spiral cotton rolls used for moisture control.
![]()
Product shot of several white cotton rolls stacked together, illustrating the absorbents mentioned in the text that block salivary ducts.
# Impression technique
---
**Impression timing**
* Inflamed gingivae are by definition swollen
* Impossible to prepare a predictable intracrevicular margin
* Impressions difficult due to uncontrolled haemorrhage
* As soon as periodontal resolution occurs there will be recession
* Therefore, achieve gingival health before embarking on definitive impressions 3-4 weeks with provisional restoration
**THE UNIVERSITY OF WESTERN AUSTRALIA | Oral Health Centre of Western Australia**
Impression technique
---
**Impression timing**
* Inflamed gingivae are by definition swollen
* Impossible to prepare a predictable intracrevicular margin
* Impressions difficult due to uncontrolled haemorrhage
* As soon as periodontal resolution occurs there will be recession
* Therefore, achieve gingival health before embarking on definitive impressions 3-4 weeks with provisional restoration
**THE UNIVERSITY OF WESTERN AUSTRALIA | Oral Health Centre of Western Australia**
## Impression Materials
### Materials for indirect restorations
**PVS – Poly Vinyl Siloxane**
**Polyether**
<img>Boxlotion
Impression Materials
### Materials for indirect restorations
**PVS – Poly Vinyl Siloxane**
**Polyether**
<img>Boxlotion
![]()
Product packaging for Aquasil Ultra Fast Set impression material with dual syringes shown.
![]()
Box and container of Aquasil Soft Putty/Regular Set impression material.
![]()
Container labeled 'Aquasil Catalyst' and a blue mixing spatula for impression material preparation.
![]()
ESPE Monophase Impression Material box with product details visible.
![]()
Two ESPE branded dual syringes for impression material application.
1-stage
2-stage
WESTERN
AUSTRALIA
Oral Health Centre
of Western Australia
1-stage
2-stage
WESTERN
Oral Health Centre
of Western Australia
![]()
Clinical photo of a dental impression under the '1-stage' heading. The image shows an orange and green alginate impression of teeth with distinct impressions of molar cusps.
![]()
Clinical photo of a blue dental impression tray or mold held by green gloved hands under the '2-stage' heading. The object appears to be a partial arch impression.
![]()
Clinical photo of a full upper jaw (maxillary) dental impression showing purple and green material under the '2-stage' heading. This is likely a comparison view to the first image.
Table 17-1 Comparative properties of impression materials*
<table>
<thead>
<tr>
<th>Type</th>
<th>Type of tray</th>
<th>Setting time</th>
<th>Ease of removal</th>
<th>Finish line readability</th>
<th>Moisture tolerance</th>
<th>Pouring time</th>
<th>Tear strength</th>
<th>Pouring ease</th>
<th>Mixing ease</th>
<th>Odor/ taste</th>
<th>Radio-paque</th>
<th>Shelf life</th>
</tr>
</thead>
<tbody>
<tr>
<td>Reversible hydrocolloid</td>
<td>Water-cooled stock metal</td>
<td>5 min</td>
<td>Very easy to easy</td>
<td>Poor</td>
<td>Excellent</td>
<td>15 min</td>
<td>Weak</td>
<td>Good to excellent</td>
<td>None is needed, but conditioning is complicated</td>
<td>Good</td>
<td>No</td>
<td>24–48 months</td>
</tr>
<tr>
<td>Polysulfide rubber base</td>
<td>Custom</td>
<td>8–14 min</td>
<td>Easy to moderate</td>
<td>Good</td>
<td>Acceptable</td>
<td>60 min</td>
<td>Good</td>
<td>Adequate to excellent</td>
<td>Moderate to difficult</td>
<td>Poor</td>
<td>Yes</td>
<td>18 months</td>
</tr>
<tr>
<td>Condensation silicone</td>
<td>Custom: two paste systems<br><br>Stock: putty/reline</td>
<td>6–10 min</td>
<td>Easy to moderate</td>
<td>Good</td>
<td>Poor</td>
<td>60 min</td>
<td>Adequate</td>
<td>Poor to fair</td>
<td>Easy</td>
<td>Good</td>
<td>No</td>
<td>12 months</td>
</tr>
<tr>
<td>Polyether rubber base</td>
<td>Custom: 4.0-mm spacer<br><br>Stock</td>
<td>4.5–6 min</td>
<td>Moderate to difficult</td>
<td>Good</td>
<td>Good</td>
<td>7 days</td>
<td>Adequate</td>
<td>Good</td>
<td>Moderate for hand-mixed; very easy for mechanically mixed</td>
<td>Poor</td>
<td>No</td>
<td>24 months</td>
</tr>
<tr>
<td>Polyvinyl siloxane</td>
<td>Stock: single units<br><br>Custom: fixed partial denture<br><br>Stock: putty/reline</td>
<td>3–8 min</td>
<td>Moderate to difficult</td>
<td>Good</td>
<td>Poor for standard hydrophobic brands; adequate for hydrophilic brands</td>
<td>7 days</td>
<td>Adequate</td>
<td>Poor for standard hydrophobic brands; adequate for hydrophilic brands</td>
<td>Easy for hand-mixed; very easy for cartridge systems</td>
<td>Good</td>
<td>No</td>
<td>24 months</td>
</tr>
</tbody>
</table>
*Based on data from O'Brien.²
Table 17-1 Comparative properties of impression materials*
<table>
<thead>
<tr>
<th>Type</th>
<th>Type of tray</th>
<th>Setting time</th>
<th>Ease of removal</th>
<th>Finish line readability</th>
<th>Moisture tolerance</th>
<th>Pouring time</th>
<th>Tear strength</th>
<th>Pouring ease</th>
<th>Mixing ease</th>
<th>Odor/ taste</th>
<th>Radio-paque</th>
<th>Shelf life</th>
</tr>
</thead>
<tbody>
<tr>
<td>Reversible hydrocolloid</td>
<td>Water-cooled stock metal</td>
<td>5 min</td>
<td>Very easy to easy</td>
<td>Poor</td>
<td>Excellent</td>
<td>15 min</td>
<td>Weak</td>
<td>Good to excellent</td>
<td>None is needed, but conditioning is complicated</td>
<td>Good</td>
<td>No</td>
<td>24–48 months</td>
</tr>
<tr>
<td>Polysulfide rubber base</td>
<td>Custom</td>
<td>8–14 min</td>
<td>Easy to moderate</td>
<td>Good</td>
<td>Acceptable</td>
<td>60 min</td>
<td>Good</td>
<td>Adequate to excellent</td>
<td>Moderate to difficult</td>
<td>Poor</td>
<td>Yes</td>
<td>18 months</td>
</tr>
<tr>
<td>Condensation silicone</td>
<td>Custom: two paste systems<br><br>Stock: putty/reline</td>
<td>6–10 min</td>
<td>Easy to moderate</td>
<td>Good</td>
<td>Poor</td>
<td>60 min</td>
<td>Adequate</td>
<td>Poor to fair</td>
<td>Easy</td>
<td>Good</td>
<td>No</td>
<td>12 months</td>
</tr>
<tr>
<td>Polyether rubber base</td>
<td>Custom: 4.0-mm spacer<br><br>Stock</td>
<td>4.5–6 min</td>
<td>Moderate to difficult</td>
<td>Good</td>
<td>Good</td>
<td>7 days</td>
<td>Adequate</td>
<td>Good</td>
<td>Moderate for hand-mixed; very easy for mechanically mixed</td>
<td>Poor</td>
<td>No</td>
<td>24 months</td>
</tr>
<tr>
<td>Polyvinyl siloxane</td>
<td>Stock: single units<br><br>Custom: fixed partial denture<br><br>Stock: putty/reline</td>
<td>3–8 min</td>
<td>Moderate to difficult</td>
<td>Good</td>
<td>Poor for standard hydrophobic brands; adequate for hydrophilic brands</td>
<td>7 days</td>
<td>Adequate</td>
<td>Poor for standard hydrophobic brands; adequate for hydrophilic brands</td>
<td>Easy for hand-mixed; very easy for cartridge systems</td>
<td>Good</td>
<td>No</td>
<td>24 months</td>
</tr>
</tbody>
</table>
*Based on data from O'Brien.²
![]()
Table 17-1: Comparative properties of impression materials. The table lists five types of dental impression materials (Reversible hydrocolloid, Polysulfide rubber base, Condensation silicone, Polyether rubber base, Polyvinyl siloxane) and compares them across multiple attributes including Type of tray, Setting time, Ease of removal, Finish line readability, Moisture tolerance, Pouring time, Tear strength, Pouring ease, Mixing ease, Odor/taste, Radio-paque status, and Shelf life.
# Monophase
<table>
<tr>
<td>
<img src="https://i.imgur.com/4i5E9fG.png"/>
</td>
<td>
preparation with retraction cord
</td>
</tr>
<tr>
<td>
<img src="https://i.imgur.com/S4e9Z9T.png"/>
</td>
<td>
preparation covered with impression material
</td>
</tr>
<tr>
<td>
<img src="https://i.imgur.com/o4G5e6i.png"/>
</td>
<td>
tray inserted with the same impression material
</td>
</tr>
</table>
Monophase
<table>
<tr>
<td>
<img src="https://i.imgur.com/4i5E9fG.png"/>
</td>
<td>
preparation with retraction cord
</td>
</tr>
<tr>
<td>
<img src="https://i.imgur.com/S4e9Z9T.png"/>
</td>
<td>
preparation covered with impression material
</td>
</tr>
<tr>
<td>
<img src="https://i.imgur.com/o4G5e6i.png"/>
</td>
<td>
tray inserted with the same impression material
</td>
</tr>
</table>
![]()
Labeled procedure image showing a dental preparation with a retraction cord placed around the gingiva to expose the margin. Caption reads: 'preparation with retraction cord'.
![]()
Labeled procedure image showing the tooth preparation covered with impression material (purple) extending over the margins. Caption reads: 'preparation covered with impression material'.
![]()
Labeled procedure image showing the impression tray inserted into the mouth with the same impression material visible between the tray and the prepared tooth. Caption reads: 'tray inserted with the same impression material'.
**Dualphase – Lightbody & Heavybody**
preparation with retraction cord
preparation covered with lightbody (LB) material
tray inserted with heavy body (HB) material
**Dualphase – Lightbody & Heavybody**
preparation with retraction cord
preparation covered with lightbody (LB) material
tray inserted with heavy body (HB) material
![]()
Diagram showing the first step of a dental impression process: preparation with retraction cord. The image displays a tooth preparation surrounded by pink gingival tissue and purple retraction cords placed at the gumline to expose the margin.
![]()
Diagram showing the second step: preparation covered with lightbody (LB) material. A yellow substance representing the light body impression material is applied around the cervical margin of the prepared tooth.
![]()
Diagram showing the third step: tray inserted with heavy body (HB) material. A blue tray containing olive-green heavy body material is being seated over the tooth, covering the previously applied light body material.
![]()
Medical diagram showing a tooth preparation with retraction cord. The image displays a cross-section of a tooth surrounded by gingival tissue and bone, with purple retraction cords placed in the sulcus to retract the gums for access.
![]()
Medical diagram illustrating the next step: preparation covered with lightbody (LB) material. A thin layer of blue impression material is shown applied over the prepared tooth margin, capturing the soft tissue interface.
![]()
Medical diagram depicting tray insertion with putty material. A thick blue putty impression material is loaded into a lighter blue rigid tray, which is then positioned over the tooth and surrounding tissues to capture the final impression.
Two-step impression with Putty
Two-step impression with Putty
![]()
A four-panel instructional diagram illustrating the 'Two-step impression with Putty' dental procedure. The panels are arranged in a sequence: top-left shows 'preparation with retraction cord'; bottom-middle shows 'Putty cut-out'; middle-top shows 'Impression with putty'; and right-side shows 'Preparation / putty cut-out covered with lightbody (LB)'. Each panel includes a cross-sectional illustration of a tooth preparation surrounded by gum tissue.
| **monophase** <br> may cause lower definition | **putty wash** <br> periodontal compression | **putty** <br> soft tray deformation |
| :--- | :--- | :--- |
| **monophase** <br> may cause lower definition | **putty wash** <br> periodontal compression | **putty** <br> soft tray deformation |
| :--- | :--- | :--- |
![]()
Medical diagram showing a 'monophase' impression tray (purple material) over teeth. The caption indicates this method 'may cause lower definition'.
![]()
Medical diagram showing a 'putty wash' technique with layered blue materials and periodontal compression around the tooth structure. Caption notes 'periodontal compression'.
![]()
Medical diagram illustrating a 'putty' technique where the soft tray deforms around the tooth. Caption states 'soft tray deformation'. Includes logos for 'The University of Western Australia' and 'Oral Health Centre of Western Australia'.
## Impression Technique
### Intraoral custom tray try-in
* Check for clearance & comfort
* Adjust if required
* Tray adhesive application
* Adhesive must be applied 15 minutes prior to impression
* Extend the adhesive over edge of tray to the outer surface of the tray
### Intraoral custom tray try-in
* Check for clearance & comfort
* Adjust if required
* Tray adhesive application
* Adhesive must be applied 15 minutes prior to impression
* Extend the adhesive over edge of tray to the outer surface of the tray
![]()
Clinical photo showing a custom dental impression tray try-in on an upper cast. The blue silicone tray is seated over the pink base of the cast to demonstrate fit and clearance.
![]()
Clinical photo demonstrating adhesive application. A cotton swab applies a substance (likely pink or purple adhesive) to the outer surface and rim of a dental impression tray.
**Impression Technique**
**Gingival displacement**
▪ Isolate prepared teeth (free from saliva and blood)
▪ Cut sufficient cord length
▪ Soak the cord in astringent / remove excess
▪ Loop the cord around the tooth and gently insert in sulcus
▪ Avoid overpacking
▪ Dry the teeth (do not desiccate)
▪ Evaluation
▪ Visualize all the margins of the preparation
▪ No soft tissue folding on the cord
The University of Western Australia | Oral Health Centre of Western Australia
**Impression Technique**
**Gingival displacement**
▪ Isolate prepared teeth (free from saliva and blood)
▪ Cut sufficient cord length
▪ Soak the cord in astringent / remove excess
▪ Loop the cord around the tooth and gently insert in sulcus
▪ Avoid overpacking
▪ Dry the teeth (do not desiccate)
▪ Evaluation
▪ Visualize all the margins of the preparation
▪ No soft tissue folding on the cord
The University of Western Australia | Oral Health Centre of Western Australia
![]()
Clinical photo showing two prepared upper teeth with visible gingival margins. The image demonstrates the state of the teeth before or during the initial phase of gingival displacement.
![]()
Clinical photo showing the same two prepared teeth after gingival displacement has been performed. Dark packing material (cord) is visible in the sulcus around the cervical margins, demonstrating the 'Gingival displacement' technique described in the text.
**Impression Technique**
**Impression material mixing**
▪ If using “cartridge” system, extrude a little impression material first
▪ Ensures an even mix of material & no blockage in the cartridge
Addition silicon:
Latex gloves may inhibit set; use vinyl or nitrile gloves
**Impression Technique**
**Impression material mixing**
▪ If using “cartridge” system, extrude a little impression material first
▪ Ensures an even mix of material & no blockage in the cartridge
Addition silicon:
Latex gloves may inhibit set; use vinyl or nitrile gloves
![]()
Photo of a dental impression cartridge system in use. The image shows a dual-syringe material cartridge (white and grey) inserted into a plunger gun with a black handle. A small amount of yellowish impression material is being extruded from the nozzle tip, visually demonstrating the technique described in the text to ensure an even mix and prevent blockage.
# Impression Technique
## Loading the tray
* Load tray with heavy body material – material slightly below level of “lip” of tray
* This should be done simultaneously with intraoral application of impression material
Loading the tray
* Load tray with heavy body material – material slightly below level of “lip” of tray
* This should be done simultaneously with intraoral application of impression material
![]()
Clinical photo showing the loading of an impression tray with blue heavy body material. The material is being poured into the tray from a container, filling it slightly below the lip level as described in the OCR text.
![]()
Photo of a dual-syringe dental mixing gun loaded with impression material (yellow and white components), illustrating the tool used for intraoral application mentioned in the context.
# Impression Technique
## Intraoral material application
* Remove cord and assess gingival tissues (10-15 seconds)
* Inject the material slowly around the preparation margins
* Proceed from the interproximal area until covering all the margins and the axial surfaces
* The tip should follow the material – avoid bubbles
* Continue in one direction, stay close to sulcus
* Once sulcus filled – cover the rest of the preparation
* Gently air-blow the material*
Intraoral material application
* Remove cord and assess gingival tissues (10-15 seconds)
* Inject the material slowly around the preparation margins
* Proceed from the interproximal area until covering all the margins and the axial surfaces
* The tip should follow the material – avoid bubbles
* Continue in one direction, stay close to sulcus
* Once sulcus filled – cover the rest of the preparation
* Gently air-blow the material*
![]()
Clinical photo showing the first step of intraoral material application: a blue syringe tip is injecting impression material around the preparation margins of posterior teeth. A metal dental instrument is retracting the gingiva to expose the sulcus.
![]()
Clinical photo showing the continuation of the procedure: the blue impression material has been injected and is now covering the preparation margins and axial surfaces. The syringe tip is positioned close to the sulcus to ensure it is filled without bubbles.
#### Syringe Application and Material Placement
1. Load the impression material into the syringe and apply it directly into the gingival sulcus.
2. Keep the tip of the syringe submerged within the impression material at all times during application to prevent the entrapment of air bubbles.
3. Continue the application until the entire preparation is covered and the sulcus is completely filled.
#### Tray Seating and Stabilization
- Seat the loaded impression tray firmly into the mouth.
- Ensure the tray is centered over the dental arch to capture all necessary anatomical landmarks.
- Hold the tray steadily in place without movement until the material has reached its final set. Refer to the manufacturer's instructions for specific setting times.
#### Impression Removal and Evaluation
- Once the material has set, remove the tray with a quick, firm pull to minimize distortion.
- Rinse the impression thoroughly under cold water to remove saliva and debris.
- Disinfect the impression according to clinical protocols.
- Inspect the final impression for accuracy, ensuring there are no voids, tears, or bubbles, particularly at the margins of the preparation.
**Impression Technique**
## Tray removal
- Hold tray in mouth until impression is set
- Optimum removal of impression tray:
- upper jaw - loosen tray on opposing side
- lower jaw - loosen tray on prep side.
- front teeth - both sides at the same time.
- Use of finger and air stream to loosen impression.
A guideline for excellent impressions in theory and practice - 3M
#### Tray Stabilization and Removal
- Hold the tray securely in the mouth until the impression material is fully set.
- Follow these protocols for optimum removal of the impression tray:
- **Upper jaw:** Loosen the tray on the opposing side first.
- **Lower jaw:** Loosen the tray on the preparation side first.
- **Front teeth:** Loosen both sides simultaneously.
- Utilize a finger and an air stream to assist in loosening the impression seal.
![]()
Annotated diagram demonstrating the optimum removal of an impression tray from a patient's mouth. The illustration is split into two parts: the top section depicts the upper jaw with arrows indicating loosening the tray on the opposing side, while the bottom section shows the lower jaw with arrows indicating loosening on the prep side. The visual context aligns with the 'Tray removal' text instructions.
# Impression Technique
**Impression inspection**
**Uniform layer of material** - Impression material is intact No damage, warping, or separation of light & heavy material
**All gingival margins are defined &**clear Includes at least 3-4 mm of **buccal**& **lingual**surfaces outside gingival margin
**Detailed, accurate occlusal surfaces** **Cusps**are sharp Tray**doesn't show through
**Distal surfaces**of molars are captured **More than half**of each molar is visible
#### Criteria for Impression Inspection
- **Uniform Layer of Material**
- The impression material must be intact.
- Ensure there is no damage, warping, or separation between the light-body and heavy-body materials.
- **Gingival Margin Definition**
- All gingival margins must be clearly defined.
- The impression should include at least 3–4 mm of buccal and lingual surfaces beyond the gingival margin.
- **Occlusal Surface Accuracy**
- Occlusal surfaces must be detailed and accurate.
- Cusps should appear sharp.
- The impression tray should not show through the material.
- **Molar Coverage**
- Distal surfaces of the molars must be captured.
- More than half of each molar should be visible in the impression.
![]()
Clinical photo of a dental impression inspection. The image shows a green dental tray containing an upper arch impression with pink tooth structures. Multiple callout annotations are present: 'Detailed, accurate occlusal surfaces' pointing to cusps; 'All gingival margins are defined & clear' indicating tissue capture; 'Distal surfaces of molars are captured' highlighting posterior teeth; 'No bubbles, voids...' in the center describing material integrity; and 'Uniform layer of material' pointing to the tray edge.
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[^1]: Original PDF page 1: [[L3 Impressions and Tissue Management.pdf#page=1|L3 Impressions and Tissue Management, p.1]]
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