BOH III Project Searches

Mick Draper
Last update February 2009

Access to PubMed

You can get PubMed from the Library Home Quick Links

From the Catalogue
From the Databases Tab

or Right Click on the link below, then click on Open Link in New Window to get the Barr Smith Library customised version of PubMed.

Customised PubMed

It may be useful to use an evidence-based approach for your project. It might be worth looking at web site below to get help with formulating database searches, critical review, integrating research into practice, and presenting options to patients.

Introduction to Evidence-Based Dentistry

In this site start with Formulating Questions go through to the end of Assessing the literature.

PICO Logic Grids
Use PICO (Population, Intervention, Comparison, Outcome) logic grid to help organize your search terms and logic.
It's always useful to have a question to begin with

What are the risks of tooth extraction for aged patients taking bisphosphonates?

The Population is aged patients using bisphosphonates.
The Intervention is tooth extraction.
In this search there isn't any comparison, and you are looking for all outcomes.

The PICO grid begins with

MeSH
Medical Subject Headings are used to describe the contents of most articles in the PubMed database. If you can find a Medical Subject Heading for each of the concepts in your grid then you should find most of the articles in PubMed.
MeSH will usually provide a definition of the terms used. This can help you to make sure that you and PubMed agree about what you are looking for.
To get access to the MeSH Database click on its link in the blue left hand sidebar.

Type in a term to describe a single concept in your search.

e.g. In a search for Diabetes in the MeSH Database type diabetes and click on Go.

you'll find that there is more than one type of diabetes.

MeSH Hierarchy
MeSH has a hierarchy of terms. It's useful to find where your concept fits in the hierarchy. This can often help you to decide to search for a broader or more specific term.

example search
If you want to find the relationship between periodontal diseases and periodontitis, look at the MeSH for periodontal diseases.
This shows the relationship of the two terms.
A MeSH search for the term Periodontal Diseases will also find all the citations to articles that have been given one of the more specific MeSH indented below Periodontal Diseases. This includes all the citations with the MeSH Periodontitis

Try to have at least one MeSH in each column of your PICO logic grid.
Can you now use the MeSH database to find appropriate MeSH for the bisphosphonates search, or for your chosen topic?

When you add a MeSH to your logic grid add [mh] after the term to force PubMed to search the term as a MeSH.

Keywords
Add words and phrases that are synonyms or alternative terms for the concepts in each of the columns in your PICO grid.
These terms are going to be useful to find citations that don't (yet) have MeSH.
What words would authors use in the titles and abstracts of their articles to describe the contents?

You should add [tiab] after the term to force PubMed to search in the titles and abstracts of citations for term.
You should consider searching most terms that are MeSH in the titles and abstracts of citations too.

Entry Terms
Entry Terms that are part of the MeSH database and can be useful sources for text words.

Here are the Entry Terms for the MeSH Acquired Immunodeficiency Syndrome

• Immunodeficiency Syndrome, Acquired
• Acquired Immunodeficiency Syndromes
• Immunodeficiency Syndromes, Acquired
• Syndrome, Acquired Immunodeficiency
• Syndromes, Acquired Immunodeficiency
• AIDS
• Acquired Immune Deficiency Syndrome
• Acquired Immuno-Deficiency Syndrome
• Acquired Immuno Deficiency Syndrome
• Acquired Immuno-Deficiency Syndromes
• Immuno-Deficiency Syndrome, Acquired
• Immuno-Deficiency Syndromes, Acquired
• Syndrome, Acquired Immuno-Deficiency
• Syndromes, Acquired Immuno-Deficiency
• Immunologic Deficiency Syndrome, Acquired

There's no point in using inverted terms such as syndrome, acquired immuno-deficiency in your PICO grid because no author would use inverted terms in a title or abstract.

Use truncation * where appropriate, but don't truncate MeSH.

infant* will find the keywords infant OR infanticide OR infantile OR infants etc

Think about British and North American spelling variations apnea OR apnoea

Now your grid will look something like this

Are there other terms that might be added to this logic grid?

Search Logic
The grid now sorts out the logic for you.
Here are the rules
Combine all the terms in the first column using OR logic.

aged[mh] OR elderly[tiab] OR dental care for aged[mh]

Do the same for each of the terms in the other columns.
Put round brackets around the terms in each column.

(aged[mh] OR elderly[tiab] OR dental care for aged[mh])

Use AND logic to join the separate column search terms.
Enter the search into the PubMed database (not the MeSH database)
Click on Go.

(aged[mh] OR elderly OR dental care for aged[mh]) AND (bisphosphonates[tiab] OR diphosphonates[mh] OR diphosphonate*[tiab] OR alendronate[tiab] OR etidronic acid[tiab]) AND (tooth extraction*[tiab]OR tooth extractions[mh] OR dental extraction*[tiab] OR tooth removal*[tiab])

Using keywords and MeSH together can increase the number of articles found.

Compare the search

aged[mh] AND diphosphonates[mh] AND tooth extractions[mh]
with the search above

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Related Articles
PubMed uses a weighted algorithm based on title words, abstract words, and MeSH to find other articles in PubMed that are similar to those you have already found.

Click on the Related Articles link to the right of a PubMed citation

What to Do When You Can't Find Anything
If you can't find a MeSH I suggest searching for your concepts in the titles of articles.
If you are looking for articles on oral health outcomes but haven't found a MeSH,

try searching for your term in the titles of citations
oral health outcomes[ti]
in the PubMed part of the database, not the MeSH Database.
If the term you are looking for is in the title then it probably means that the article is about that concept.

Change the display from Summary to Citation
This will show the MeSH added to the citations found by the search.

Now you can combine the relevant MeSH Oral Health and Outcome Assessment Health Care, to search for the concept,
and I'd recommend that you look at both of these MeSH in the MeSH Database to view broader and more specific MeSH, and the Entry Terms for possible [tiab] keywords to add to your search.

Study Types
Do you need to add a study type to the results?
Are you looking for systematic reviews, or randomized controlled trials, or some other study type?
Right Click on the button below then click on Open Link in New Window to find links to PubMed searches on particular study types.

PubMed Searches on Study Types

We can't run rcts on topics such as periodontitis and preterm birth, so what's the best study type for investigating a link between these?
Go to the web site on Evidence based practice above and look at the section on the hierarchy of evidence.

Now you can add your search terms to the appropriate study type to find citations to articles that are on your topic that have used the appropriate study type.

If You Find Too Much That Isn't Relevant
Here are some ways to restrict the number of citations found.

Major MeSH
Using Major MeSH for one or more term can help you to focus your search to the most relevant articles.

(oral health[mh] OR dentistry[mh]) AND (group process[mh] OR cooperative behavior[mh] ) AND (learning[mh] OR education[mh])

finds more than 380 citations.
You should consider changing at least some of these MeSH to Major MeSH.

(oral health[mh] OR dentistry[mh]) AND (group process[majr] OR cooperative behavior[majr] ) AND (learning[majr] OR education[majr])

This search has reduced the citations found by an order of magnitude, and should have made the results more relevant as well.

Limit Searches Using MeSH Subheadings
Example search

dental materials/adverse effects[mh] AND dentin sensitivity[mh]

Find the first MeSH Dental Materials
and click in the box to the left of the subheading adverse effects
(You can select more than one subheading. The searches for MeSH and the different subheadings will be combined using OR logic)

Limiting Using PubMed Systematic Review filter
Click on Clinical Queries in the blue left hand sidebar in the PubMed Database

Enter your search.

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PubMed Limits
If you find too many citations, or you want to limit citations to particular languages, dates etc, you can use PubMed limits.
The search

(dental caries[mh] OR caries[tiab] OR dental decay[tiab] OR tooth decay[tiab]) AND preventive dentistry[majr]

finds finds more than 2,600 citations, using limits can reduce this.

Click on the Limits tab.

You can limit by date

You can limit to humans, and/or English
But using Humans will mean that you lose all the 'in process' and 'as supplied by publisher' citations.
The same is true of several other limits available here.

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Click on Go at the top or bottom of the screen to enforce the Limits.

Click on the tick in the Limits tab to remove limits, otherwise the limits will stay in place for subsequent searches.

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First year School of Dentistry PubMed Tutorial

A more advanced PubMed tutorial

The official PubMed Tutorial from the (US) National Library of Medicine

Other Databases

In particular you might look at Cochrane Library for oral health systematic reviews

Begin by looking at the Cochrane Oral Health Group abstracts

Then use a title search in Cochrane Library

You can try your PubMed search in Scopus
This is even bigger than PubMed but has less dentistry

If you're looking for stats then try

Australian Research Centre for Population Oral Health

University of Adelaide Library's Dentistry Site