Unprotected Bruxism — Direct Tooth-on-Tooth Force Transmission
Nocturnal grinding sends unfiltered clenching force straight through enamel into the jaw joint.
- 20–40: Bruxism episodes (per night, untreated)
- ≤250 lb: Peak nocturnal bite force (far above chewing loads)
- ~8%: Sleep bruxism prevalence (of adults)
- Elevated: TMJ compressive stress (no cushioning present)
Tooth-on-tooth contact
Enamel surfaces grind directly against each other, no buffer layer.
Force pathway
Clenching force travels straight through the tooth into the joint.
Unbuffered nocturnal force is a leading driver of TMJ overload.
Muscle overactivity
Masseter and temporalis fire well above normal resting tone.
Splint Fitted — A Cushioning Layer Enters the Bite
A custom occlusal splint is placed between the arches, breaking direct contact.
- Hard acrylic: Splint material (custom-milled or heat-formed)
- 2–3: Fabrication visits (impression, fit, adjust)
- 1–4 mm: Thickness range (titrated per patient)
- Full arch: Arch coverage (even splint contact)
Physical barrier
The splint interposes a rigid layer between upper and lower teeth.
Custom fit
Impressions ensure even contact across every tooth surface.
Thickness selection
Thicker splints cushion more but shift jaw position further.
Splint thickness is tuned per patient to balance comfort and protection.
Force Redistribution — Spreading the Bite Load
The splint surface disperses concentrated bite force across a broader area.
- ~3×: Contact area increase (vs. bare cusp contact)
- ≤50%: Peak force reduction (at the tooth surface)
- Even contact: Occlusal scheme (flat splint plane)
- Lowered: Pressure per tooth (load shared across arch)
Wider contact plane
Flat splint geometry spreads point loads into a broad surface.
Softened force lines
Force disperses laterally before reaching the joint.
Redistribution alone can roughly halve peak transmitted force.
Thickness scaling
Greater thickness disperses force over a larger splint area.
Reduced Muscle Activity — Calming the Jaw Muscles
Shifting the bite position lowers overactive masseter and temporalis firing.
- 30–40%: Masseter EMG reduction (with splint in place)
- +1–3 mm: Vertical dimension change (jaw opens slightly)
- Reduced: Muscle fatigue (lower sustained tone)
- Decreased: Morning jaw pain (patient-reported)
Bite position shift
A slightly opened vertical dimension relaxes muscle proprioceptors.
Lower EMG activity
Recorded muscle activity drops noticeably during splint-wear nights.
Calmer muscles mean less sustained clenching force overall.
Fatigue reduction
Muscles spend less of the night in sustained contraction.
Joint Load Reduction — Protecting the TMJ Over Time
Cumulative force, area, and muscle effects lower nightly TMJ compressive stress.
- ≤70%: TMJ stress reduction (combined splint effect)
- Improved: Long-term joint protection (with consistent use)
- Stabilized: Disc position (reduced compressive drift)
- Majority: Patient-reported relief (report reduced symptoms)
Cumulative protection
Redistribution and calmer muscles together spare the joint.
Sustained benefit
Consistent nightly use compounds protection over months.
Long-term splint use is linked to lower TMJ symptom scores.
Ongoing monitoring
Thickness and fit are periodically reassessed by a dentist.