Pathologic calcification is seen in
Systemic sclerosis:

Characterized by ultimate induration and atrophy of skin and fixation of epidermis to deeper subcutaneous tissues. The skin becomes hardened and atrophic and cannot be wrinkled or picked up because of its firm fixation to the deep connective tissue. This contracture of skin gives a mask-like appearance to the face of claw-like appearance to hands.
Scleroderma can be circumscribed (morphea) or linear (Coup de sabre).
The tongue becomes stiff and board like, causing the patient difficulty in eating and speaking.
Reduced opening of mouth and fixation of jaw as a result of involvement of the peritemporo mandibular joint tissues making dental care very difficult.
Some times deposition of calcium in affected areas is also found.

Radiographic features:
-     Extreme widening of PDL, two to four times normal thickness is diagnostic.
-    Bone resorption of angle of mandibular ramus and partial or complete resorption of condyles and/or coronoid processes of the mandible are also seen.

Overall, increased collagen in tissues is characteristic feature of systemic sclerosis or scleroderma.
Scleroderma
Lichen planus
Dystrophic epidermolysis bullosa
Lupus erythematosus