Nowitzki and Landry left the Rockets' 116-108 overtime victory after Nowitzki's elbow caught Landry in the mouth as he drove to the basket early in the second quarter.
Landry was called for fouling Nowitzki as the eight-time All-Star drove hard to his left to set up a short jumper and caught Landry with his right elbow.
Landry was taken to an emergency room for treatment.
The Mavericks found pieces of two teeth imbedded in Nowitzki's elbow and had to spend 30 minutes cleaning the cut before adminstering X-rays, which were found to be negative.
Nowitzki missed the team's practice on Saturday and is listed as questionable for the game against Cleveland on Sunday with a deep laceration in the elbow.
Nowitzki shot two free throws left-handed immediately after the play. By taking the free throws -- Nowitzki made 1 of 2 -- he remained eligible to return to the game.
But a return was ruled out entering the fourth quarter, with Nowitzki having received three stitches.
Marc Stein is a senior NBA writer for ESPN.com.