The normal resting position of teeth refers to the way the upper and lower teeth come together when the jaw is relaxed and not actively chewing or speaking. This is also known as the postural position or physiologic rest position of the jaw. Understanding the normal resting tooth position is important in dentistry and orthodontics for evaluating bites and occlusion.
What is occlusion?
Occlusion refers to the way the upper and lower teeth come together and make contact. Good occlusion is important for proper chewing and even distribution of forces on the teeth. There are four aspects of normal occlusion:
- Anterior teeth guidance – The upper front teeth slightly overlap the lower front teeth vertically and are slightly in front of them horizontally.
- Posterior teeth support – The molars and premolars support the bite when the jaw is closed.
- Simultaneous anterior and posterior contact – There is even contact among anterior and posterior teeth when closing into maximum intercuspation.
- Well-aligned arches – The upper and lower teeth fit properly without crowding or spacing.
Ideal resting tooth position
When the teeth are in an ideal resting position, there is a natural balance between the elevator muscles that close the jaw and the depressor muscles that open the jaw. The teeth sit lightly together, with the following features:
- The top and bottom front teeth overlap slightly vertically, with the upper front teeth in front of the lower.
- The back teeth are not touching but have a natural space between them.
- The midlines of the arches line up.
- The lips are gently touching with the mouth slightly open.
This allows the jaw to rest in a relaxed, lightly closed position. The teeth are not clenched or grinding. The jaw muscles are not contracted to hold the mouth closed.
Factors affecting resting tooth position
There are several factors that can affect the normal resting position of teeth:
Tooth alignment and spacing
Crowded, rotated, or misaligned teeth can prevent the arches from fitting properly together. Spacing between teeth also affects resting position.
Missing teeth
Missing teeth, such as due to extractions or congenitally missing teeth, allow too much space between arches.
Extra teeth
Extra teeth, such as supernumerary or impacted teeth, can crowd the arches.
Jaw discrepancies
Mismatched sizes of the upper and lower arches, abnormal jaw growth, or jaw joint disorders can affect occlusion and resting tooth position.
Tooth wear
Excessive tooth wear or chewing surfaces from grinding can alter the resting tooth position over time.
Dental restorations
Dental work such as fillings, crowns, bridges, implants, or dentures that are not properly fitted can interfere with normal resting occlusion.
Habits
Oral habits such as tongue thrusting, mouth breathing, nail biting, and chewing on lips/cheeks can influence tooth position and arch development.
Normal resting tooth position by age
The natural resting tooth position varies slightly at different ages:
Infants/toddlers
- No teeth in infancy
- Primary teeth are present around ages 2-3 years
- Primary teeth meet edge-to-edge with 1-2 mm overjet
- Slight spaces are normal between teeth
Mixed dentition
- Combination of primary and permanent teeth around ages 6-12 years
- Molars overlap cusp-to-cusp
- Front teeth overlap and fit edge-to-edge
- Can have slight dental midline discrepancy
Adolescent dentition
- All permanent teeth except 3rd molars around ages 12-17 years
- Front teeth overlap 1-2 mm with upper incisor edges overlapping lower incisor edges
- Back teeth touch lightly or have slight separation when mouth is at rest
- Dental midlines coincide
Adult dentition
- All permanent teeth present by late teens/early 20s
- Front teeth vertically overlap 1-2 mm
- Posterior teeth are in light contact or slightly apart with even separation between arches
- Midlines match up
- Well-aligned arches with proper anterior guidance
Normal resting vertical dimension
The vertical dimension of occlusion (VDO) refers to the distance between the jaws when teeth are in resting position. Normal VDO ranges between:
- When anterior teeth are overlapping: 2-4 mm of separation between back teeth
- When anterior teeth are edge-to-edge: 0-2 mm of separation between back teeth
The VDO can be reduced if excessive tooth wear has occurred over time. Determining the optimal VDO is important when planning dental restorations.
Determining normal resting tooth position
Dentists determine normal resting tooth position and occlusion through several means:
Observation
- Note overlap of front teeth
- Note space between back teeth
- Check midline alignment
- Watch lip closure at rest
Palpation
- Feel for muscle tenderness by gently palpating jaw muscles
- Joint sounds or discomfort can indicate problems
Radiographs
- Dental x-rays show overall tooth angulation, alignment, and occlusal contacts
- Panoramic films give overview of entire mouth
- Bitewings assess resting contacts
Dental impressions
- Models made from impressions precisely record tooth positions
- Clinician can visualize occlusion on models
Occlusal analysis
- Marks are placed on teeth to identify occlusal contacts
- Patient closes teeth together into normal resting position
- Contacts between arches are mapped
Malocclusion and resting tooth position
Malocclusion refers to misalignment of the teeth resulting in abnormal contact between upper and lower arches. Some features of malocclusion include:
- Deep overbite – Upper front teeth excessively overlap lower teeth vertically
- Anterior open bite – Lack of vertical overlap between front teeth
- Overjet – Upper front teeth are too far forward of lower front teeth
- Crossbite – Upper and lower teeth overlap incorrectly left-to-right
- Crowding – Lack of space for all teeth to align normally
- Spacing – Excess space between some or all teeth
These all affect the normal resting tooth position. Malocclusion may lead to uneven wearing of tooth surfaces, chewing and biting difficulty, jaw pain, and speech impediments. Orthodontic treatment can correct malocclusion and establish a normal resting tooth position.
Bruxism and abnormal resting tooth position
Bruxism is clenching or grinding of the teeth, which can occur during sleep or while awake. This can cause the jaw muscles to hold tension and the teeth to be in constant contact rather than a normal resting position. Signs of bruxism include:
- Worn down tooth surfaces
- Chipped or cracked teeth
- Flattened tooth cusps
- Jaw muscle tenderness
- Headaches or ear pain upon waking
Custom night guards and addressing sources of stress can help manage bruxism. However, severe bruxism may alter the natural resting tooth position over time.
Effects of abnormal resting tooth position
When the resting tooth position is not ideal, several problems may occur:
- Jaw pain or soreness from constant muscle contraction
- TMJ disorders from uneven joint forces
- Chipped or cracked teeth from occlusion trauma
- Tooth wear or flattening from friction
- Chewing difficulty from poor alignment
- Excessive strains on teeth leading to loose teeth or gum disease
- Speech impediments certain sounds
- Difficulty finding a comfortable bite position
It is important to address abnormal resting tooth positions through orthodontics or restorative treatments to prevent damage long-term.
Ideal resting tooth position with orthodontics
Orthodontic treatment can establish an ideal resting tooth position through:
- Straightening misaligned teeth into proper positions
- Closing excess space between teeth
- Opening space between crowded teeth
- Coordinating arches for ideal fit of upper and lower teeth
- Aligning midlines
- Leveling planar surfaces
- Achieving cusp-to-fossa occlusion between upper and lower molars/premolars
- Slight vertical overlap and horizontal overjet of front teeth
- Light contact between posterior teeth when mouth is relaxed
Retainers help stabilize teeth in the new corrected resting position after orthodontic appliances are removed.
Restoring ideal resting tooth position
Restorative dental treatments can also help re-establish normal resting tooth position:
- Dental fillings can rebuild worn, fractured, or decayed teeth
- Dental crowns can cover misshapen or worn teeth
- Bridges replace missing teeth to prevent shifting
- Implants restoresingle missing teeth
- Partial/full dentures replace multiple missing teeth
- Occlusal adjustments and night guards manage occlusion strains
Cosmetic recontouring or reshaping can also optimize the shape and position of teeth.
Maintaining ideal resting tooth position
After orthodontic treatment or dental restorations establish an optimal resting tooth position, maintaining this position is crucial. Recommendations include:
- Wearing retainers as prescribed
- Avoiding teeth grinding and clenching
- Replacing worn tooth surfaces to maintain occlusion
- Using a night guard if grinding occurs, especially during sleep
- Visiting the dentist regularly for occlusal evaluation and restorative care
- Practicing good oral hygiene to prevent tooth decay or gum disease
Conclusion
The normal resting tooth position involves a relaxed and lightly closed jaw with slight overlap of the front teeth, light contact between back teeth, well-aligned arches, and an even bite distribution. This ideal resting position allows proper chewing function and reduces strain on the teeth, muscles, and TMJs. Orthodontics can correct abnormal occlusion, and restorative dentistry can rebuild a normal resting bite. Maintaining optimal tooth position then requires retaining corrections, protecting against damage from bruxism, replacing worn teeth, and visiting the dentist regularly.
