As per Oracle documentation and my understanding, there is no TIME datatype.

Character Data Types
    CHAR(size)
    VARCHAR2(size)
    NCHAR(size)
    NVARCHAR2(size)
    CLOB
    NCLOB

Numeric Data Types
    NUMBER(p,s)
    FLOAT
    BINARY_FLOAT
    BINARY_DOUBLE

Date and Time Data Types
    DATE
    TIMESTAMP
    TIMESTAMP WITH TIME ZONE
    TIMESTAMP WITH LOCAL TIME ZONE
    INTERVAL YEAR TO MONTH
    INTERVAL DAY TO SECOND

Binary Data Types
    RAW(size)
    LONG RAW
    BLOB

Rowid Data Types
    ROWID
    UROWID

Other Data Types
    BFILE
    XMLType
    Object Types
    Collection Types

In Oracle, a DATE is a binary data-type that consists of 7-bytes representing: century, year-of-century, month, day, hour, minute and second. It ALWAYS has those components so you can always store the time component with the date. Oracle does NOT have a separate TIME data-type.

Your statement should be:

CREATE TABLE Appointment
(
  Appt_ID   INTEGER,
  Pt_ID,
  Proc_ID,
  Prov_ID,
  Tooth_Num INTEGER,
  Tx_Cost   NUMBER(8,2),
  Appt_Date DATE,
  CONSTRAINT PK_Appointment PRIMARY KEY (Appt_ID),
  CONSTRAINT FK_Appointment_Pt_ID FOREIGN KEY (Pt_ID) REFERENCES Patient (Pt_ID),
  CONSTRAINT FK_Appointment_Proc_ID FOREIGN KEY (Proc_ID) REFERENCES Procedure (Proc_ID),
  CONSTRAINT FK_Appointment_Prov_ID FOREIGN KEY (Prov_ID) REFERENCES Provider (Prov_ID)
);

Note: you do not need to specify the data-type for columns that are part of a foreign key constraint. If you omit the data-type then Oracle will infer the data-type from the referenced columns and this ensures that your columns always have data-types that match the columns that they reference.

Note 2: If the client application you are using is not displaying the time component for the DATE then change the settings on the client application (i.e. SQL Developer) or use TO_CHAR(appt_date, 'YYYY-MM-DD HH24:MI:SS') to format the date when you display it – Oracle ALWAYS stores both date and time components for a DATE data-type.

Note 3: PROCEDURE is a keyword in Oracle – while you can use it as an identifier (as it is not a reserved word), it might be better to call the table something else, such as PROCEDURES, to avoid confusion.

If you really must have separate date and time columns then you can use an INTERVAL DAY(0) TO SECOND(0) data-type to store a time – but then you would have a time component in both appt_date and appt_time which may be confusing (and redundant).

fiddle