This is an appeal by John Latta (Claimant) from part of the order of the Workmen’s Compensation Appeal Board (Board) *363which affirmed a referee’s decision awarding Claimant total disability benefits beginning June 10, 1987, but denying benefits to Claimant from January 2, 1980 through June 10, 1987. We affirm.
The facts leading up to the present claim petition are set forth in Latta v. Workmen’s Compensation Appeal Board (Latrobe Die Casting) (“Latta I ”), 98 Pa.Commonwealth Ct. 56, 510 A.2d 896 (1986), petition for allowance of appeal denied, 514 Pa. 637, 522 A.2d 1106 (1987), where this court affirmed that portion of a Board order denying Claimant total disability benefits after December 4, 1979.
Claimant filed the present reinstatement petition on March 27, 1987, alleging entitlement to total disability benefits beginning January 2,1980. In support, Claimant presented his own testimony and the testimony of Dr. Roger Searfoss, who examined Claimant on September 12, 1980, and again on June 10, 1987.
The referee found the following. Dr. Searfoss determined at the June 10, 1987 examination that Claimant could not perform his pre-injury work, but he could perform light duty work, for which he had previously been released by Dr. Searfoss in 1977. Based upon the approval of light-duty work, Employer offered Claimant work, which was approved by Dr. Searfoss on April 21, 1988. Claimant did not actually begin work until November 28, 1988, however, because of physical conditions unrelated to his work injury.
The referee determined that Claimant was entitled to total disability payments beginning June 10, 1987, the date of Dr. Searfoss’ examination of Claimant, until November 28, 1988, when Claimant actually began work, and beginning again on December 30, 1988, the date Claimant was laid off. As to Claimant’s claim for benefits from January 2, 1980 through June 10, 1987, the referee determined that Claimant was not permitted to relitigate matters decided prior to the filing of his present claim petition on March 27, 1987 because these matters had been previously litigated in Latta I. Claimant appealed the referee’s decision in part, alleging that he was entitled to total disability benefits from January 2, 1980 *364through June 10, 1987. The Board affirmed the referee. Claimant now appeals to this court.
On appeal, the issue raised by Claimant is whether the Board erred in determining that res judicata barred Claimant’s claim for total disability benefits from January 2, 1980 through June 10, 1987. Our scope of review is limited to a determination of whether constitutional rights have been violated, whether an error of law has been committed, or whether the referee’s necessary findings of fact are supported by substantial evidence. Wells-Moore v. Workmen’s Compensation Appeal Board (McNeil Consumer Products, Co.), 144 Pa.Commonwealth Ct. 382, 601 A.2d 879 (1992).
Res judicata, or claim preclusion, is a generic term used by courts and litigants to refer to the various ways in which a judgment in an action will have a binding effect in a later action. Hebden v. Workmen’s Compensation Appeal Board (Bethenergy Mines), 142 Pa.Commonwealth Ct. 176, 597 A.2d 182 (1991), petition for allowance of appeal granted, 529 Pa. 659, 604 A.2d 251 (1992). The fundamental principle underlying res judicata is that a judgment should be conclusive as between the parties and their privies in respect to every fact which properly could have been considered in reaching the determination and in respect to all points of law relating directly to the cause of action and affecting the subject matter before the court. Id. Res judicata bars not only matters which were actually litigated, but also matters which could have been litigated at the first proceeding if they were part of the same cause of action. Id.
Claimant argues that his claim for total disability benefits from January 2, 1980 through June 10, 1987 is not barred by res judicata because Latta I only addressed a period which ended December 4, 1979, and the present petition for reinstatement alleges a date of disability beginning January 2, 1980. A claimant seeking to have suspended benefits reinstated is required to show that his earning power is again affected by his disability, and that the disability which gave rise to his original claim, in fact, continues. Dancison v. Workmen’s Compensation Appeal Board (Penn Hills Senior *365High School Claims Management Services), 145 Pa.Commonwealth Ct. 10, 602 A.2d 423 (1992). In order to establish a continuing disability, a claimant is required to produce unequivocal medical testimony. See Pieper v. Ametek-Thermox Instruments Division, 526 Pa. 25, 584 A.2d 301 (1990); Latta I.
The only medical evidence Claimant presented as to his disability in support of his present petition for reinstatement, was the testimony of Dr. Searfoss. Dr. Searfoss examined Claimant on September 12,1980, and then not again until June 10, 1987. However, the results of the September 12, 1980 examination, which Claimant wishes to introduce in the present case to support his claim for benefits beginning in 1980, are part of the first claim petition that Claimant filed in Latta I.
In Latta I Claimant petitioned for reinstatement of benefits, beginning “as of October 20, 1979, and continuing to date,” that date being the date of filing of the claim petition on March 12, 1982. Claimant’s Latta I Claim Petition. Moreover, the factual record in Latta I was not closed until March 3, 1983. Certainly, Claimant had available to him in Latta I the results of the September 12, 1980 examination, which he should have and could have used as evidence to sustain his burden. However, Claimant failed to produce this evidence,1 and as a result the referee, and subsequently this court, determined that Claimant did not show that his disability continued after December 4, 1979. Therefore, Claimant cannot now use the results of the 1980 examination in support of his present petition to reinstate benefits because the state of Claimant’s disability during the time period from October 20, 1979 until March 3, 1983 was already litigated in Latta I.
However, Claimant can use the results of Dr. Searfoss’ June 10, 1987 examination, which establish Claimant’s petition as a new claim for total disability benefits beginning on June 10, *3661987. See Kanyan v. Workmen’s Compensation Appeal Board (Helvetia Coal Co.), 125 Pa.Commonwealth Ct. 173, 557 A.2d 792 (1989). Although Claimant’s claim for disability from January 2, 1980 through March 3, 1983 is barred by res judicata, Claimant’s second claim for disability benefits beginning on June 10, 1987 is not barred by res judicata.2
Accordingly, the order of the Board is affirmed.
ORDER
AND NOW, November ), 1992, the order of the Workmen’s Compensation Appeal Board in the above-captioned matter is affirmed.
. In fact, Claimant states in his brief: "Truth was that the 9/12/80 examination by Dr. Searfoss was not used in the earlier proceedings because it was completely forgotten by the Claimant.” Claimant's Brief at 7.
. Claimant also argues that the referee failed to make crucial findings of fact regarding Claimant’s disability from January 2, 1980 through June 10, 1987. However, because of our resolution of the res judicata issue, we need not address this argument.