Three quick answers first:
Fell into my hand
Upper teeth falling into the hand are money in Al-Nabulsi ("a property that comes to him") and profits in the Ibn Sirin compilation. But if you caught them — took them in your hand as they fell — the same page of Al-Nabulsi says your children are cut off. Landing and catching are not the same event to these books.
Fell into my lap
A son. Both books say it in the three-surface rule; the compilation repeats it twice more elsewhere in the same entry. The caught-version again flips it: teeth taken "in his lap" belong to the line-cutting clause.
Fell to the ground / disappeared
Al-Nabulsi calls it "the calamity of death"; the compilation says "they mean death" for upper teeth on the floor. But the grimmest version needs a missing tooth: in Al-Nabulsi, a tooth that falls and is lost is the death or absence of the relative it stands for — a tooth that falls and stays in your hand has not crossed that line.
The three surfaces, in both books
Al-Nabulsi — upper teeth only
"If one sees that his upper teeth fell into his hand, it is a property that comes to him; if they fell into his lap, it is a male child; and if they fell to the ground, it is the calamity of death."
Ibn Sirin compilation — same trio, same order
"If the upper teeth fall into one's hand in the dream, they represent profits. If they fall in his lap in the dream, they mean a son, and if they fall on the floor in the dream, they means death."
Same three surfaces, same three outcomes, same order, and both books apply the trio only to the upper teeth. That is not coincidence of two independent witnesses — the 1992 compilation drew on the same Arabic dream literature al-Nabulsi (four centuries later than Ibn Sirin's era) belongs to. Read the agreement as inheritance.
Classical textFor the lower teeth, neither book uses the surfaces
Ask "what if the lower teeth fell into my hand?" and both books go quiet on landing. They answer a different question instead:
"If one sees that his lower teeth fell, he will be struck by pain, ache, worry and grief."
"If the lower teeth fall in the dream, they mean pain, sufferings, sorrows and distress."
Surface matters for the upper jaw; the lower jaw gets read by feel — pain, worry, grief — wherever it falls. One page of Al-Nabulsi even converts a surface-free lower-tooth fall into coin:
"And whoever saw them fall into his palm without pain or handling, they are dirhams according to their number."
Where the page rules against itself
Further down the same page ص180, Al-Nabulsi states the catching rule:
"If one sees that his teeth fall while he takes them in his hand, or with his beard, or in his lap, that indicates that his children will be cut off and no child will be born to him."
Put the two blocks side by side: a tooth that lands in your lap is a male child; teeth you gather into your lap end your line. The hand that profits is the hand the teeth fell into, not the hand that grabbed them. The book never reconciles this; this page simply does not either. The compiled Ibn Sirin carries the same collision inside one entry:
"If one collects one's lost teeth in a dream it means longevity, or it could mean having a large progeny. … If one collects his fallen teeth in a dream, it also means that he can no longer conceive children."
Collecting means a crowd of descendants in one line of the same entry and no children at all in another. The compilation prints both, three sentences apart in the flow, and moves on.
Classical textThe pocket: a fourth surface
Al-Nabulsi adds one landing place the trio misses — cloth, i.e. wrapping the tooth up. It reads as gain, not loss:
"If he saw that an incisor fell into his hand or he wrapped it in his garment, he gains a son, or a brother, or a sister."
The honest gap
Read search questions into these pages and they partly go unanswered. Neither book distinguishes a right hand from a left, or specifies which relative the "son" of a lap-fall is. In Al-Nabulsi, the ground reading ("calamity of death") and the lost-tooth reading ("death of the relative it refers to") are stated as separate rules on one page and never merged. Anyone who tells you the classical books have a settled rule for every hand-and-tooth combination is filling a gap the books left open.
Why the dream feels so physical
The same modern study every mainstream page cites for the stress reading actually points somewhere else. Rozen & Soffer-Dudek (Frontiers in Psychology 9:1812, 2018 — PubMed 30319507) surveyed 210 undergraduates: teeth dreams correlated with teeth tension — waking tenderness or tension in teeth, gums, or jaws (r = 0.21, p < 0.005) — but not with the item asking directly about teeth grinding (r = 0.06, not significant), and not with psychological distress (r = 0.02, not significant), while other dream types did correlate with distress. The authors' reading: most people who grind or clench at night don't know they do it, but they wake feeling the tension — and the dream may be that feeling, distorted.
For scale, they cite sleep-bruxism figures from other research: 85–90% of people grind their teeth at some point in life; active sleep bruxism sits at about 8.6% of the general population (Khoury et al., 2016, as cited in that paper). In Calvin Kai-Ching Yu's Dream Motif Scale survey (Dreaming, 22(1), 2012, pp. 18–52, DOI 10.1037/a0026171), 39.0% of respondents reported teeth dreams at least once, 16.2% recurrently, 8.2% regularly — figures as reported in Rozen & Soffer-Dudek (2018).
Now set the two layers beside each other — this page's actual point. The study never asked where the teeth landed. "Hand, lap, or floor" is not a variable in any modern design; the research tracks a jaw-state on waking, the classical page tracks a family ledger and a debt roll, and the only thing either layer can say about the other is that they are measuring different things. If you woke with a tight jaw and a memory of teeth in your palm, the physical reading and the classical reading are not competing answers; the books were written centuries before bruxism had a name.
This page reports what two classical texts say. It is not a prediction, a medical or religious ruling, and no dream book — classical or modern — settles what a dream means for the person who had it.