Risks & complications of wearing a dental bridge
Placement of bridges, whether permanent or removable, has permanent consequences
In addition to the numerous risks and side effects applying to most or all conventional (invasive) dental treatment addressed at Drilling & filling teeth: an unwise choice?, this page lists specific problems relating to the placement and wearing of a dental bridge in your mouth, including advice for those who develop toothache under bridgework.
One of the most invasive and serious-in-consequences dental treatments in my eyes since in order to bridge a missing tooth, the adjacent possibly perfectly healthy teeth must be reduced (filed down) to mere stubs.
So in case you ever wanted to forego the bridge and "go in the buff", you are left not only with one (or more) missing tooth/teeth (your previous gap) but with a gap plus two or more tiny stubs (and which are likely to not survive in the longer (or even shorter) term due to pulp and other serious damage they have sustained).
So here is a concise (not necessarily exhaustive) list of "risks and side effects" associated with dental bridge placement.
1 Destruction of large amounts of sound tooth structure
Placing a bridge depends on sacrificing large amounts of sound tooth structure in the teeth serving as the abutments.
2 Damage to the pulp of the abutment teeth
During the preparatory filing down of the abutments, the pulp (nerve) is traumatized/damaged and possibly killed. Should the dentist not take enough time (time is money!) in the process of preparing the bridge's abutments (file them down too fast), the excess heat generated will damage or kill the pulp of the formerly healthy tooth (more details at Drilling & filling teeth: an unwise choice?).
A dead pulp of course means a dead tooth (until the day that humankind will have discovered ways of revitalizing defunct tooth pulp). In my personal experience, bridge pillars are literally condemned to death, but according to dentist Dr. Graeme Munro-Hall, "the greater the amount of enamel left behind after a tooth is prepared for a crown or bridge, the greater the chance of survival for that tooth."
3 Insufficient fit and structural issues
A smaller or larger gap between the gums and the artificial tooth (the pontic or "dummy tooth") allows food rests and bacteria to infiltrate. These will settle inside the bridge and cause inflammation as well as tooth decay (secondary caries) - unless perhaps the mouth is constantly rinsed with antibacterial solutions.
Such a gap can exist from the moment the bridge is placed (due to faulty craftsmanship) or develop gradually (personally I developed a large gap in a bridge placed in my upper jaw, probably due to the gum above the dummy tooth starting to recede).
Incorrectly adjusted masticatory surfaces (fitting surfaces) of the teeth lead to structural stress (malocclusion).
4 Cracks, breaks, chips or warping
The bridge can become unstable, making chewing difficult.
The bridge can warp leading to problems with chewing and talking as well as great pain.
Ceramic bridges can crack or break. A porcelain fracture (a crack developing in the false tooth) will open the gumline leading to pain and infection. Breaking and cracking is particularly likely when chewing hard food items (such as nuts, ice, etc.).
In fact, I have seen an express warning to not chew hard food at all when carrying a bridge in one's mouth.
Porcelain or plastic veneers fused to metal bridges can chip off or gradually abrade (wear away), making the tooth look unattractive.
5 Tooth grinding and clenching
6 Other potential problems with dental bridges
The gums can be injured.
The gums can become diseased, as can the periodontium (tissues surrounding and supporting the teeth which maintain them in the jaw) which can lead to tooth loss.
If a bridge is placed with existing gingivitis, the gingivitis will be exacerbated and abutment teeth will loosen.
7 Bridges in the upper jaw vs. bridges in the lower jaw
Strictly speaking from personal experience, bridges placed in the upper jaw will much more quickly develop "issues" such as slightly receding gums leading to bacterial infiltration and cavities on the abutments.
8 Advice for those who wear a bridge and who develop pain
If you develop the slightest (or even more so, a stubborn type of) toothache under a bridge (such as after drinking something sweet, biting down etc.), you may wish to rush to the dentist to have the bridge removed. Waiting without applying strong proactive measures (see below) will just give the bacteria time to eat into your hapless teeth trapped under the bridge.
Whenever I waited to have this done, all that happened was that the respective infected pillar “rotted away” under cover while giving me great pain until it was finally released from its prison (which I had long hesitated to do since I resented paying another lump sum for the work of a few minutes).
Incidentally, the concomitant root infection in one case was healed by a homeopathic remedy that a spiritual naturopath correctly determined as being right for me by using a biotensor (a “high-tech” pendulum).
There are however several potential (at least temporary) "get-out clauses" to the above. For one thing, you can try keeping the beginning infection at bay with chlorhexidine (make sure to thoroughly soak the entire mouth) or other strong (preferably natural) antiseptics (e.g. various essential oils) as well as stepping up (or beginning) to do xylitol rinses.
You may also wish to start incorporating any of these Tooth root infection remedies.
Perhaps the best solution, however, is the following:
My best friend continues to very successfully use (easily doable) urine rinses to keep a would-be infection under a lower-jaw bridge under total control (the infection possibly being caused by slight gum recession in the bridge area, allowing food rests and bacteria to infiltrate).
Each day the bridge happens to "report back for duty", she holds urine in her mouth for up to twenty minutes and any discomfort typically vanishes within ten minutes or so (she rarely ingests a very small amount as well). Some (in fact more and more) days are completely free of any sign of discomfort, possibly due to the gums having recuperated to form a tight seal again and the infection having been eliminated.
She also uses several additional approaches to combat infection including some of those listed on Tooth root infection remedies but it seems it's the urine rinses which provide the most instantaneous and reliable relief (and what currently looks like actual healing - it is now many weeks since she last had a feeling of irritation under that bridge).
Since chlorhexidine rinses or daily application of a natural essential-oil-based antiseptic also give very good results, she alternates between these and the urine rinses for maintenance and prevention of any future infection (regular xylitol rinses and a tooth-friendly diet being a matter of course).
So if for whatever reason you wish (or have to) keep a bridge in your mouth which seems to want to develop a beginning infection, uropathy (which has also helped with other serious dental issues such as advanced tooth root infection) is most definitely worth a try and as a side effect, should benefit your teeth and body in other ways as well.
More at Urine therapy for the healing of teeth and gums, including a caveat regarding the simultaneous application of antiseptics.
Update June 2014: A second person with even more advanced pain and infection under bridgework has reported a resounding success partially owed to urine therapy. She too included other measures such as colloidal silver, MSM, propolis, vitamin C, peppermint essential oil, and flossing the area with floss that had been soaked in a strong salt solution for several hours, while making sure to apply all antiseptic measures well apart from the urine treatment (for the reasons see Urine therapy [scroll to "Caveat: to be on the safest side, never mix urine with any antiseptic substance"].
1 See the detailed report under Deep-seated tooth root infection cured with homeopathics.